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Investigation of the "Arena Zagreb" multifunctional hall´s roof

Profile image of Mladenko RakMladenko Rak

2009

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Abstract

The structure consists of curved steel girders suspended over L=104 m span by means of cables system and of suspenders. The investigation of girders was conducted so that hangers were suspended from the main girder’ s medium nodes. The platforms for loads amounting from the total of 440 kN were fastened to the suspenders. The investigation was conducted throughout 5 phases. The vertical deflections, deformations (in each main cables), dynamic investigation were conducted. Results were compared for experimental and numerical investigation.

Figures (532)

2. Experimental results
2. Experimental results
The frequency of segment formation is usually higher than 10 kHz, which is above the level of conventional response of classical sensors. By releasing the shear energy of the lamella, a far more dominant peak source is observed in the signal of vibrations in case of production of saw-tooth chips. This is best illustrated by test data, Figure 2. 4. References Fig. 2: Parameters of median and frequency changes depending on the chip structure.
The frequency of segment formation is usually higher than 10 kHz, which is above the level of conventional response of classical sensors. By releasing the shear energy of the lamella, a far more dominant peak source is observed in the signal of vibrations in case of production of saw-tooth chips. This is best illustrated by test data, Figure 2. 4. References Fig. 2: Parameters of median and frequency changes depending on the chip structure.
Metallography can be routinely used to study porosity in AlSi castings. Fig. 1: Casting pores in AISi7Mg by metallography
Metallography can be routinely used to study porosity in AlSi castings. Fig. 1: Casting pores in AISi7Mg by metallography
Fig. 2: Largest pore sizes in Al-Si alloy by metallography Measurements of largest pore equivalent sizes found in a_ significant number of metallographic fields of view can be discussed in the light of the Gumbel’s distribution, [2]. An example of largest pore size data sets (i.e. Maximum Feret Diameter) entered into the Gumbel plot is shown in Fig. 2. Since each data set appreciably fulfills the linearity condition, the Gumbel statistical distribution can be used for fitting and extrapolation. The slope of the regression line is an indicator of the scatter in the data. Inspection of Fig. 2 shows that set A (modified with Na and cast in steel mold) has the largest scatter among the three materials while set B (modified with Sr and cast in steel mold) and C (modified with Sr and sand cast) have similar and reduced scatter.
Fig. 2: Largest pore sizes in Al-Si alloy by metallography Measurements of largest pore equivalent sizes found in a_ significant number of metallographic fields of view can be discussed in the light of the Gumbel’s distribution, [2]. An example of largest pore size data sets (i.e. Maximum Feret Diameter) entered into the Gumbel plot is shown in Fig. 2. Since each data set appreciably fulfills the linearity condition, the Gumbel statistical distribution can be used for fitting and extrapolation. The slope of the regression line is an indicator of the scatter in the data. Inspection of Fig. 2 shows that set A (modified with Na and cast in steel mold) has the largest scatter among the three materials while set B (modified with Sr and cast in steel mold) and C (modified with Sr and sand cast) have similar and reduced scatter.
representing pixel by pixel the absorption coefficient of the material crossed by X-rays. From these scans, cross-section images (i.e. slices) of the material volume are obtained with a back-projection algorithm. The second step of the procedure is the 3D reconstruction of pores from the series of slices. An original software has been developed to obtain all the pores inside the volume under investigation (i.e. a cylinder 4 mm in diameter and 1 mm in length shown in Fig. 3).
representing pixel by pixel the absorption coefficient of the material crossed by X-rays. From these scans, cross-section images (i.e. slices) of the material volume are obtained with a back-projection algorithm. The second step of the procedure is the 3D reconstruction of pores from the series of slices. An original software has been developed to obtain all the pores inside the volume under investigation (i.e. a cylinder 4 mm in diameter and 1 mm in length shown in Fig. 3).
the original pore. Therefore guidelines for estimating representative pore sizes based on coalescence conditions of neighboring pores are needed. Fig. 5: Cross-section of a shrinkage pore
the original pore. Therefore guidelines for estimating representative pore sizes based on coalescence conditions of neighboring pores are needed. Fig. 5: Cross-section of a shrinkage pore
The schematic draw of the testing equipment is shown in Fig. 1.
The schematic draw of the testing equipment is shown in Fig. 1.
solution was stored in a furnace and after each and every test the physiologic solution was changed for a new 37°C solution.
solution was stored in a furnace and after each and every test the physiologic solution was changed for a new 37°C solution.
The maximal force curve in the function of the travel distance is shown in Figure 2. Fig. 1: Maximal force — travel displacement for the tested sample The maximal force is given by the test results because it was recorded in the function of the travel distance and the cross section is detailed in Table 1. The trend of the curves is similar in all the four case, after loading they have a faster uploading. In two cases the first 5mm travel distance don’t need a considerable force. The prepared samples are not rigid samples and it happens that the length of the sample remains longer after fixation than the 5mm distance between the two grips.
The maximal force curve in the function of the travel distance is shown in Figure 2. Fig. 1: Maximal force — travel displacement for the tested sample The maximal force is given by the test results because it was recorded in the function of the travel distance and the cross section is detailed in Table 1. The trend of the curves is similar in all the four case, after loading they have a faster uploading. In two cases the first 5mm travel distance don’t need a considerable force. The prepared samples are not rigid samples and it happens that the length of the sample remains longer after fixation than the 5mm distance between the two grips.
4. Discussion
4. Discussion
Fig. 1: Tower with positions of measuring cross- sections, second level enumeration of strain gauges. Corresponding author: danko.radica@fesb.hr
Fig. 1: Tower with positions of measuring cross- sections, second level enumeration of strain gauges. Corresponding author: danko.radica@fesb.hr
Fig. 2: Characteristic time interval for wind 3ora on second sensor level
Fig. 2: Characteristic time interval for wind 3ora on second sensor level
Fig. 4: RLCC of Bora (load case 1) rrom recorded data 1t 1S ODV1OUS that tower response on wind load is predominantly in first vibration mode what is agreement with [3]. and the respective frequency is 0.97 Hz.
Fig. 4: RLCC of Bora (load case 1) rrom recorded data 1t 1S ODV1OUS that tower response on wind load is predominantly in first vibration mode what is agreement with [3]. and the respective frequency is 0.97 Hz.
Fig. 1.3 shows a more realistic design of the sleeve and fig. 1.4 represents a combination model 2 and model 3.
Fig. 1.3 shows a more realistic design of the sleeve and fig. 1.4 represents a combination model 2 and model 3.
3. Conclusions
3. Conclusions
Fig. 1: Mesh model of the delaminated plate in the figure 2, the numerical and experi- mental results for the case of delamination placed in the symmetry axis is presented. In the figure 3, the test rig is presented.
Fig. 1: Mesh model of the delaminated plate in the figure 2, the numerical and experi- mental results for the case of delamination placed in the symmetry axis is presented. In the figure 3, the test rig is presented.
3. Acknowledgments
3. Acknowledgments
Fig. 3: Variation Test rig Fig. 2: Variation of maximum transversal displacement versus inplane load. Case of the delamination placed between layers 8 and 9
Fig. 3: Variation Test rig Fig. 2: Variation of maximum transversal displacement versus inplane load. Case of the delamination placed between layers 8 and 9
‘ig. 1: Views of real specimen with installed FBG before and after the pressure test. Composite rotation-symmetrical elements (e.g. pressure vessels, pipes, shafts, mast, etc.) are most often fabricated from long fibers by winding technology. That method is completely automated and widespread [1-2]. The composite layers are packed in an ord programmed way in compliance with oadings. The braiding method for c ered and foreseen omposite elements manufacturing is new and a echnique in comparison with classica from 5° to 86°. Furthermore that makes possible embedding additional create so called “smart materia embedded other layers (i.e. with ternative winding method [2] and allows realization of reinforcement layer at an any angle in a range echnique elements between composite layers. It is possible to ” s” with specific magnetic properties) as well as sensors (ie. optical fiber based ones), which locally measure strain and temperature distribution composite material. Ss inside
‘ig. 1: Views of real specimen with installed FBG before and after the pressure test. Composite rotation-symmetrical elements (e.g. pressure vessels, pipes, shafts, mast, etc.) are most often fabricated from long fibers by winding technology. That method is completely automated and widespread [1-2]. The composite layers are packed in an ord programmed way in compliance with oadings. The braiding method for c ered and foreseen omposite elements manufacturing is new and a echnique in comparison with classica from 5° to 86°. Furthermore that makes possible embedding additional create so called “smart materia embedded other layers (i.e. with ternative winding method [2] and allows realization of reinforcement layer at an any angle in a range echnique elements between composite layers. It is possible to ” s” with specific magnetic properties) as well as sensors (ie. optical fiber based ones), which locally measure strain and temperature distribution composite material. Ss inside
Fig. 2: Exemplary force — strain and force — displacement curves for specimen with reinforcement angle 30° [5]. Fig. 2: Exemplary force — strain and force — displacement curves for specimen with reinforcement angle 30° [5]. During the test a compressive force (pressure), displacement of pistons as well as deformation (strain) in circumferential direction were measured. Because of large deformation on the outer surface of specimens, even few percents, Fiber Bragg Gratings (FBG) for strain measurements were used. It let to perform strain measurement very precisely in a wide range [3,4] which was not possible to obtain by classical method (electric resistance wire strain gauge).
Fig. 2: Exemplary force — strain and force — displacement curves for specimen with reinforcement angle 30° [5]. Fig. 2: Exemplary force — strain and force — displacement curves for specimen with reinforcement angle 30° [5]. During the test a compressive force (pressure), displacement of pistons as well as deformation (strain) in circumferential direction were measured. Because of large deformation on the outer surface of specimens, even few percents, Fiber Bragg Gratings (FBG) for strain measurements were used. It let to perform strain measurement very precisely in a wide range [3,4] which was not possible to obtain by classical method (electric resistance wire strain gauge).
4. References 3. Summary Fig. 3: Average values of circumferential strains for three different tube types: 30°, 45° and 60° in a function of applied load [5]. It was a result of a matrix failure in composite. So called delamination between two phases (glass fiber and epoxy resin) occurred. It was also o moment when a specimen started to whiten (see fig. 1). Maximal registered strain by FBG sensors reached 2.5% (25000 ts).
4. References 3. Summary Fig. 3: Average values of circumferential strains for three different tube types: 30°, 45° and 60° in a function of applied load [5]. It was a result of a matrix failure in composite. So called delamination between two phases (glass fiber and epoxy resin) occurred. It was also o moment when a specimen started to whiten (see fig. 1). Maximal registered strain by FBG sensors reached 2.5% (25000 ts).
Fig. 4: Comparison of circumferential strain for tube specimen 30° [5].
Fig. 4: Comparison of circumferential strain for tube specimen 30° [5].
The attacked locality becomes the anode and the surrounding surface becomes the cathode, which is considerably larger then the anode. Cations M"" hydrolyse and pH in the pit is rapidly decreasing (Fig. 1). The fall of pH inside the pit supports its farther growth. The last phase of the pit's development is its repassivation, which is achieved by the decrease of potential on the value of the
The attacked locality becomes the anode and the surrounding surface becomes the cathode, which is considerably larger then the anode. Cations M"" hydrolyse and pH in the pit is rapidly decreasing (Fig. 1). The fall of pH inside the pit supports its farther growth. The last phase of the pit's development is its repassivation, which is achieved by the decrease of potential on the value of the
Fig. 2 S-N curves of AISI 316L and AISI 316Ti steels Fatigue investigations were carried out under fully reversed axial loading in the region from N = 10° to N = 10° cycles using high- frequency resonant ultrasonic machine. Fatigue tests were conducted under constant amplitude loading at a load ratio R = -1, frequency f ~ 20 kHz and ambient temperature, using smooth specimens with polished surface.
Fig. 2 S-N curves of AISI 316L and AISI 316Ti steels Fatigue investigations were carried out under fully reversed axial loading in the region from N = 10° to N = 10° cycles using high- frequency resonant ultrasonic machine. Fatigue tests were conducted under constant amplitude loading at a load ratio R = -1, frequency f ~ 20 kHz and ambient temperature, using smooth specimens with polished surface.
Fig. 3 Fatigue fractures and corrosion pits Surface crack initiation due to the formation of extrusion and intrusion during fatigue test was typical for the both steels (AISI 316L and AISI 316Ti) without corrosion damage. On the other hand, after corrosion damage, both steels were characteristic by fatigue crack initiation from the corrosion pits on the surface (Fig. 3). In this case the fatigue crack initiation was highly shortened due to the occurrence of corrosion pits and the total number of cycles was very close to the number of cycles of fatigue crack propagation.
Fig. 3 Fatigue fractures and corrosion pits Surface crack initiation due to the formation of extrusion and intrusion during fatigue test was typical for the both steels (AISI 316L and AISI 316Ti) without corrosion damage. On the other hand, after corrosion damage, both steels were characteristic by fatigue crack initiation from the corrosion pits on the surface (Fig. 3). In this case the fatigue crack initiation was highly shortened due to the occurrence of corrosion pits and the total number of cycles was very close to the number of cycles of fatigue crack propagation.
Fig. 1: Crack in concrete, microscopic observation. Many contact methods and contactless methods are available, based on mechanical, optical and electric measurement for crack width changes in time: deformeters, mechanical indicators, enlarging magnifiers, microscopes, inductive potentiometer sensors, string tensometers, and optical sensors with optical fibres. 3. Crack width
Fig. 1: Crack in concrete, microscopic observation. Many contact methods and contactless methods are available, based on mechanical, optical and electric measurement for crack width changes in time: deformeters, mechanical indicators, enlarging magnifiers, microscopes, inductive potentiometer sensors, string tensometers, and optical sensors with optical fibres. 3. Crack width
Fig. 2: Crack width evaluation by proper software. 4. Conclusions
Fig. 2: Crack width evaluation by proper software. 4. Conclusions
Fig. 1. Schedule of the Quasi-Steady Method. The quasi-steady method assumes that the characteristics of a propeller in each phase of unsteady motion are approximated by those in uniform flow at the same phase. Thus, if the non- uniform flow field is known around a propeller from experiments, the flow speed and the angle of attack at each phase are easily calculated according to the diagram represented in fig. 1.
Fig. 1. Schedule of the Quasi-Steady Method. The quasi-steady method assumes that the characteristics of a propeller in each phase of unsteady motion are approximated by those in uniform flow at the same phase. Thus, if the non- uniform flow field is known around a propeller from experiments, the flow speed and the angle of attack at each phase are easily calculated according to the diagram represented in fig. 1.
Taking into account the overall dimensions of a concrete 55,000 tdw bulk carrier having a four- bladed propeller with a diameter D = 6.4 m, and using the flow-chart shown in fig. 3, one can obtain the corresponding results for the computed propeller torque and thrust amplitudes and phases.
Taking into account the overall dimensions of a concrete 55,000 tdw bulk carrier having a four- bladed propeller with a diameter D = 6.4 m, and using the flow-chart shown in fig. 3, one can obtain the corresponding results for the computed propeller torque and thrust amplitudes and phases.
Fig. 3. Flow-chart for the Calculation of the Propeller Harmonic Excitations. 4. References 3. Experimental investigations The prediction capacity of the theoretical models was check on physical model. Experiments have been carried-out at the Romanian Ship Research and Design Institute ICEPRONAV Galatz-Romania on dummy model (scale 1:30) in order to determine in the towing tank the nominal wake, the loading coefficients and the efficiency (fig. 4 and 5). The torque and thrust fluctuations were determinate in a cavitation tunnel with a propeller dynamometer in the measurement section 850x850 mm. The data from this device may be digitally read and automatically recorded by a
Fig. 3. Flow-chart for the Calculation of the Propeller Harmonic Excitations. 4. References 3. Experimental investigations The prediction capacity of the theoretical models was check on physical model. Experiments have been carried-out at the Romanian Ship Research and Design Institute ICEPRONAV Galatz-Romania on dummy model (scale 1:30) in order to determine in the towing tank the nominal wake, the loading coefficients and the efficiency (fig. 4 and 5). The torque and thrust fluctuations were determinate in a cavitation tunnel with a propeller dynamometer in the measurement section 850x850 mm. The data from this device may be digitally read and automatically recorded by a
Fig. 4. Measurement Devices: 1-Dynamometer; 2-Am- plifier; 3-Printer; 4-Swich; 5-Osciloscop; 6-Dynamic Analyzer; 7-Recorder.
Fig. 4. Measurement Devices: 1-Dynamometer; 2-Am- plifier; 3-Printer; 4-Swich; 5-Osciloscop; 6-Dynamic Analyzer; 7-Recorder.
The torsion angle of the ship hull model cross section is determined by taking into account the displacements of the points placed on the outline (fig. 1), according to the rotation of the rigid body (thin-walled beam hypothesis).
The torsion angle of the ship hull model cross section is determined by taking into account the displacements of the points placed on the outline (fig. 1), according to the rotation of the rigid body (thin-walled beam hypothesis).
7. References Fig. 3: Variation of the relative normal stress in the midship open section
7. References Fig. 3: Variation of the relative normal stress in the midship open section
Fig. 5: Variation of the relative torsion angle along the ship model The variation of the relative torsion angle (¢,/M,.) along the ship model obtained so from FEM analysis, thin-walled beam theory and from experimental measurements is presented in figure 5. As it is seen in figure 5, the maximum value of the parameter (¢,/M,) in the midship (open section type) is almost 2 times more than the maximum torsion angle in the closed area.
Fig. 5: Variation of the relative torsion angle along the ship model The variation of the relative torsion angle (¢,/M,.) along the ship model obtained so from FEM analysis, thin-walled beam theory and from experimental measurements is presented in figure 5. As it is seen in figure 5, the maximum value of the parameter (¢,/M,) in the midship (open section type) is almost 2 times more than the maximum torsion angle in the closed area.
The force amplitude was decreased in consecutive tests from 11 KN to 5.3 KN as to obtain stress amplitudes from about 160 MPa to 75 MPa as shown in Tab. 1.
The force amplitude was decreased in consecutive tests from 11 KN to 5.3 KN as to obtain stress amplitudes from about 160 MPa to 75 MPa as shown in Tab. 1.
Tab. 1: Fatigue data obtained for ZK60 alloy.
Tab. 1: Fatigue data obtained for ZK60 alloy.
Some SEM analyses revealed that this material contains mangan and_ titanium, although it should be 98 % magnesium and 2 % zirconium and silicium. As seen in Fig. 2 voids are inevitable. Fig. 2: SEM analyses of ZK60.
Some SEM analyses revealed that this material contains mangan and_ titanium, although it should be 98 % magnesium and 2 % zirconium and silicium. As seen in Fig. 2 voids are inevitable. Fig. 2: SEM analyses of ZK60.
The corresponding S-N curve is represented in Fig. 1. Although not too many data are available up to now, we may suggest that a reasonable value for the fatigue limit could be 100 MPa.
The corresponding S-N curve is represented in Fig. 1. Although not too many data are available up to now, we may suggest that a reasonable value for the fatigue limit could be 100 MPa.
Fig. 3: Histeresis loops obtained during a test at an amplitude of 150 MPa. However, another test at an amplitude of 75 MPa didn’t lead to the failure of the specimen. It is interesting to monitor the histeresis loops during each test. Just as an example, in Fig. 3 the first 100 cycles, the middle ones, and the last 100 cycles are shown.
Fig. 3: Histeresis loops obtained during a test at an amplitude of 150 MPa. However, another test at an amplitude of 75 MPa didn’t lead to the failure of the specimen. It is interesting to monitor the histeresis loops during each test. Just as an example, in Fig. 3 the first 100 cycles, the middle ones, and the last 100 cycles are shown.
Fig. 1: Specimens type, dimensions and injection gates; position of micro-CT examined samples. The effect of injection point location was analyzed both in light of fibre orientation and of the elastic properties computed by a micro- mechanical model based on the Cell Method, introduced in [4].
Fig. 1: Specimens type, dimensions and injection gates; position of micro-CT examined samples. The effect of injection point location was analyzed both in light of fibre orientation and of the elastic properties computed by a micro- mechanical model based on the Cell Method, introduced in [4].
The experimental results of the fatigue tests are shown in fig. 2. Fig. 2: S-N curves for specimens with lateral notches.
The experimental results of the fatigue tests are shown in fig. 2. Fig. 2: S-N curves for specimens with lateral notches.
Fig. 4: Preferred fibre orientation with respect to specimen y axis (above), and Index of Anisotropy IA (below), at different z positions (mm), core layer. Fig. 3: Lateral and longitudinal injection, point A, core layer: t-CT reconstruction.
Fig. 4: Preferred fibre orientation with respect to specimen y axis (above), and Index of Anisotropy IA (below), at different z positions (mm), core layer. Fig. 3: Lateral and longitudinal injection, point A, core layer: t-CT reconstruction.
Fig. 5: Apparent elastic modulus (MPa) along specimen x axis, at different z positions (mm), core layer.
Fig. 5: Apparent elastic modulus (MPa) along specimen x axis, at different z positions (mm), core layer.
Fig. 1: Indentation curves of a-B,C thin film measured at room and elevated temperature.
Fig. 1: Indentation curves of a-B,C thin film measured at room and elevated temperature.
Fig. 2: Indentation hardness and reduced modulus of a-B,C film versus temperature.
Fig. 2: Indentation hardness and reduced modulus of a-B,C film versus temperature.
There are often applied machines in the min- ing of the lignite coal about the long operating period frequently reaching 50 years [2]. There- fore the analyses of the state of these machines are being conducted in order to determine the alternative of their exploitation or replacing it by new. One of examinations conducted at this occasion there are measurements of oscillation and dynamic influences during mining [1]. These examinations are aimed at determining real dynamic loading and the scope of changes of stresses which can be a base for determining the fatigue life of elements of the load-carrying system [3]. Linking experimental methods with numerical methods it is possible on the basis of measurements in selected points to appoint the state of stresses and deformations in the entire load-carrying system. Fig. 1: View of RS-560 chain excavator
There are often applied machines in the min- ing of the lignite coal about the long operating period frequently reaching 50 years [2]. There- fore the analyses of the state of these machines are being conducted in order to determine the alternative of their exploitation or replacing it by new. One of examinations conducted at this occasion there are measurements of oscillation and dynamic influences during mining [1]. These examinations are aimed at determining real dynamic loading and the scope of changes of stresses which can be a base for determining the fatigue life of elements of the load-carrying system [3]. Linking experimental methods with numerical methods it is possible on the basis of measurements in selected points to appoint the state of stresses and deformations in the entire load-carrying system. Fig. 1: View of RS-560 chain excavator
Because of great loadings of the central part of the excavator sensors were arranged, as it is showed on fig. 2. The measurements were con- ducted during the mining in different locations of the bucket chain boom. The instance course of changes of accelerations registered in the middle part in measuring point 6 was shown on fig. 3. On the basis of these courses a amplitude spectrum of accelerations was determined in the form like on fig. 4.
Because of great loadings of the central part of the excavator sensors were arranged, as it is showed on fig. 2. The measurements were con- ducted during the mining in different locations of the bucket chain boom. The instance course of changes of accelerations registered in the middle part in measuring point 6 was shown on fig. 3. On the basis of these courses a amplitude spectrum of accelerations was determined in the form like on fig. 4.
Fig. 4: Widmo amplitudowe przyspieszen. Fig. 3: Course of acceleration changes in point 6.
Fig. 4: Widmo amplitudowe przyspieszen. Fig. 3: Course of acceleration changes in point 6.
The influence of measured dynamic loads on the load-carrying structure of the excavator was determined with the help of computer simula- tions. A FEM shell-beam model was built [4, 5] in I-DEAS NX software shown on fig. 5. Fig. 5: FEM model of load-carrying structure of excavator
The influence of measured dynamic loads on the load-carrying structure of the excavator was determined with the help of computer simula- tions. A FEM shell-beam model was built [4, 5] in I-DEAS NX software shown on fig. 5. Fig. 5: FEM model of load-carrying structure of excavator
Fig. 6: Huber-Misses stresses distribution comming from dynamic loadings
Fig. 6: Huber-Misses stresses distribution comming from dynamic loadings
apex), and in two deck structure cross sections, in total in 16 measuring points (Fig. 2).
apex), and in two deck structure cross sections, in total in 16 measuring points (Fig. 2).
Fig. 8: PSD record (1* and 3" natural frequency) Table 1 shows the comparison of the first 10 experimentally and numerically determined natural frequencies. Figure 8 shows the record
Fig. 8: PSD record (1* and 3" natural frequency) Table 1 shows the comparison of the first 10 experimentally and numerically determined natural frequencies. Figure 8 shows the record
During the load testing displacements were measured in two lines, above all the supports and in the centres of deck structure span. Figure 7 graphically presents experimentally and numerically determined displacements for the 7” loading phase in which maximal displacements were measured.
During the load testing displacements were measured in two lines, above all the supports and in the centres of deck structure span. Figure 7 graphically presents experimentally and numerically determined displacements for the 7” loading phase in which maximal displacements were measured.
Fig 7. Comparison of experimental and numerical displacements for the 7" loading phase 4. Conclusions
Fig 7. Comparison of experimental and numerical displacements for the 7" loading phase 4. Conclusions
A wide range of systems has been developed to control the position of running metal bands. This paper deals with the mostly used guiding system, which controls the position of the metal band changing the skewing angle B of a tail pulley. system is shown in figure 1. by This
A wide range of systems has been developed to control the position of running metal bands. This paper deals with the mostly used guiding system, which controls the position of the metal band changing the skewing angle B of a tail pulley. system is shown in figure 1. by This
Figure 2: Mechanical model A of the metal band II) Bending theory of second order with consid- eration of the shear deformation - friction contact between band and pulleys
Figure 2: Mechanical model A of the metal band II) Bending theory of second order with consid- eration of the shear deformation - friction contact between band and pulleys
Figure 5: Representative measurement results The results were verified by measurements as well. Two strain gauges were applied on the metal band with a dis The results had and the glue on he band had to in figure 5 for ance of 11.5 mm to the band edge. o be multiplied by an increase factor o get the effective stresses in the band edge. Because of the small thickness of the band (0.3 mm) he influence of the thickness of the strain gauges the effective strain on the surface of be considered. The results are shown a skewing angle of 0.211° and a prestressing of 100 N/mm. Summary of the results
Figure 5: Representative measurement results The results were verified by measurements as well. Two strain gauges were applied on the metal band with a dis The results had and the glue on he band had to in figure 5 for ance of 11.5 mm to the band edge. o be multiplied by an increase factor o get the effective stresses in the band edge. Because of the small thickness of the band (0.3 mm) he influence of the thickness of the strain gauges the effective strain on the surface of be considered. The results are shown a skewing angle of 0.211° and a prestressing of 100 N/mm. Summary of the results
Figure 4: Representative results of FEM The finite elements method was used to verify the calculated results. The stresses for the band between the pulleys are illustrated in figure 4 for a skewing angle of 0.211° and a prestressing of 100 N/mm?. Since a fixed contact was chosen between the band and the pulleys the bending stress, which is caused by the curvature of the band, is not included in the results. The effective stresses for the points B1 and B2 follows as:
Figure 4: Representative results of FEM The finite elements method was used to verify the calculated results. The stresses for the band between the pulleys are illustrated in figure 4 for a skewing angle of 0.211° and a prestressing of 100 N/mm?. Since a fixed contact was chosen between the band and the pulleys the bending stress, which is caused by the curvature of the band, is not included in the results. The effective stresses for the points B1 and B2 follows as:
Figure 7: Results for point B1 and B2 contact with the tail pulley (point Al and A2). In figure 7 the results are stated for the points B1 and B2. where the band is in contact with the pulley. Two conditions have to be fulfilled to prevent the band from damage and to ensure a safe band run:
Figure 7: Results for point B1 and B2 contact with the tail pulley (point Al and A2). In figure 7 the results are stated for the points B1 and B2. where the band is in contact with the pulley. Two conditions have to be fulfilled to prevent the band from damage and to ensure a safe band run:
Fig. 1: Isometric view of testing facility. It is equipped by twenty-one hydraulic actuators. A real time control system guarantee synchronous application of each kind of load history on bogie frame. Here, a set of ad hoc fittings and twenty-one actuators guarantee load application, on each direction, on wheels, with the superposition of twist [2]. The same apply
Fig. 1: Isometric view of testing facility. It is equipped by twenty-one hydraulic actuators. A real time control system guarantee synchronous application of each kind of load history on bogie frame. Here, a set of ad hoc fittings and twenty-one actuators guarantee load application, on each direction, on wheels, with the superposition of twist [2]. The same apply
Tab. 1: Typical calibration and uncertainty parameters. Prior to effectuate the required tests on the bogie, a method to evaluate calibration curves of measurement chain and uncertainty has been established. A typical flow chart is shown in tab. 1, where statistical data are calculated from strain gauges data and used to evaluate some commonly accepted parameters. Typically, more than seventy strain gauges are applied on a bogie frame.
Tab. 1: Typical calibration and uncertainty parameters. Prior to effectuate the required tests on the bogie, a method to evaluate calibration curves of measurement chain and uncertainty has been established. A typical flow chart is shown in tab. 1, where statistical data are calculated from strain gauges data and used to evaluate some commonly accepted parameters. Typically, more than seventy strain gauges are applied on a bogie frame.
Fig. 1: The RSPS test- geometrical model with boundary conditions All the operator’s protective structures must meet the requirements of standard PN-92/G- 59001 “Self- propelled mining machines — Rock Slide protective structures for operator — Requirements and Tests”, that describes the required tes s as a dynamic loading of a protective structure by the impact on the upper part of the structure of the research bob that falls on the s tructure with the potential energy E regard to impact point (presented on figure 1).
Fig. 1: The RSPS test- geometrical model with boundary conditions All the operator’s protective structures must meet the requirements of standard PN-92/G- 59001 “Self- propelled mining machines — Rock Slide protective structures for operator — Requirements and Tests”, that describes the required tes s as a dynamic loading of a protective structure by the impact on the upper part of the structure of the research bob that falls on the s tructure with the potential energy E regard to impact point (presented on figure 1).
Fig. 2: The RSPS test- « displacement contours for the maximal deflection. The results of the analyses in the form of displacement contours are shown in Figure 2.
Fig. 2: The RSPS test- « displacement contours for the maximal deflection. The results of the analyses in the form of displacement contours are shown in Figure 2.
The measurement results show the good conformity with the results from numerical simulations. The permanent plastic displacement and concerned with _ that deflection in the impact area amount to 42mm. In the numerical analysis the permanent deflection amounts to 17mm. Fig. 5: The graph of vertical displacements for chosen points of the operator cabin
The measurement results show the good conformity with the results from numerical simulations. The permanent plastic displacement and concerned with _ that deflection in the impact area amount to 42mm. In the numerical analysis the permanent deflection amounts to 17mm. Fig. 5: The graph of vertical displacements for chosen points of the operator cabin
Fig. 4: Experiment - view of the cabin with the loading bob In the range of experimental test (verification test) the destructive strength test was conducted on the prototype of a protective structure. The impact energy of the research bob was 60000J according to the RSPS standard. The view of the test is presented on figure 3 together with the graph of the defection of the selected point measured by the Polytec Laser vibrometer PS V-400-B.
Fig. 4: Experiment - view of the cabin with the loading bob In the range of experimental test (verification test) the destructive strength test was conducted on the prototype of a protective structure. The impact energy of the research bob was 60000J according to the RSPS standard. The view of the test is presented on figure 3 together with the graph of the defection of the selected point measured by the Polytec Laser vibrometer PS V-400-B.
Fig. 6: . Displacement in the selected point — laser vibrometer measurement
Fig. 6: . Displacement in the selected point — laser vibrometer measurement
Fig. 1: Two modes of deformation due to fatigue damage: a) cyclic plasticity and b) ratcheting. Two modes of deformation mechanism due o deve he firs cycling plastici band parame opment of a fatigue damage process can be distinguished depending on a kind of metal and its state defined by manufacture process. In one deformations which occur due to loading are governed by cyclic y tule as a result of micro slip and slip decohesion. The fatigue indicator er can be defined in the case based on changes of the strain amplitude for a constant stress amplitude of a cyclic loading as shown on Fig. la.
Fig. 1: Two modes of deformation due to fatigue damage: a) cyclic plasticity and b) ratcheting. Two modes of deformation mechanism due o deve he firs cycling plastici band parame opment of a fatigue damage process can be distinguished depending on a kind of metal and its state defined by manufacture process. In one deformations which occur due to loading are governed by cyclic y tule as a result of micro slip and slip decohesion. The fatigue indicator er can be defined in the case based on changes of the strain amplitude for a constant stress amplitude of a cyclic loading as shown on Fig. la.
The high cycle fatigue (HCF) tests were performed using hourglass specimens shown on Fig.2. Specimens were cut out from a railways wheel made of the P54T alloyed steel with chemical composition as given in Tab.1. Specimens were machining in such a way that all machine traces were along the specimen axis. Fig. 2: Specimen on the left side and special griping system used in the HCF tests.
The high cycle fatigue (HCF) tests were performed using hourglass specimens shown on Fig.2. Specimens were cut out from a railways wheel made of the P54T alloyed steel with chemical composition as given in Tab.1. Specimens were machining in such a way that all machine traces were along the specimen axis. Fig. 2: Specimen on the left side and special griping system used in the HCF tests.
An exemplary and typical for the tested material behavior is shown on Fig. 3 for specimen under stress amplitude equal to 400 MPa. Fig. 3: The stress - strain curves of a selected cycles for specimen P1 tested under stress amplitude equal to 400 MPa. A stress — strain curve in a sequential cycles has the same elastic form and shifts in the direction of tension for increasing number of cycles. Development of damage due to cycle loading leads to ratcheting and in consequence to fracture of specimen. The tested material exhibit increase value of a mean strain ¢,, with growing number of cycles in loading under constant stress amplitude and zero value of a mean stress. The inelastic strain ¢;, equal to a width of the hysteresis loop has a constant value up to the last period of the lifetime when increases rapidly just before fracture of specimen. The ratcheting in a form of a growing value of a mean strain is a main mechanism of damage development in high cycle fatigue for the tested P54T steel. And the mean value of strain in one cycle can be consider as a fatigue indicator parameter and The additional information on _ strain response of material in sequential cycles of a constant stress amplitude enable us to define: a type of a damage mechanism, a fatigue indicator parameter, a development of damage, and the most important, a range of the applicability of the linear accumulation fatigue rule if exist at all. The information enable us to distinguish subsets of experimental points of the S/N curve which corresponds to different distribution of initial inclusions in the measuring part of specimen.
An exemplary and typical for the tested material behavior is shown on Fig. 3 for specimen under stress amplitude equal to 400 MPa. Fig. 3: The stress - strain curves of a selected cycles for specimen P1 tested under stress amplitude equal to 400 MPa. A stress — strain curve in a sequential cycles has the same elastic form and shifts in the direction of tension for increasing number of cycles. Development of damage due to cycle loading leads to ratcheting and in consequence to fracture of specimen. The tested material exhibit increase value of a mean strain ¢,, with growing number of cycles in loading under constant stress amplitude and zero value of a mean stress. The inelastic strain ¢;, equal to a width of the hysteresis loop has a constant value up to the last period of the lifetime when increases rapidly just before fracture of specimen. The ratcheting in a form of a growing value of a mean strain is a main mechanism of damage development in high cycle fatigue for the tested P54T steel. And the mean value of strain in one cycle can be consider as a fatigue indicator parameter and The additional information on _ strain response of material in sequential cycles of a constant stress amplitude enable us to define: a type of a damage mechanism, a fatigue indicator parameter, a development of damage, and the most important, a range of the applicability of the linear accumulation fatigue rule if exist at all. The information enable us to distinguish subsets of experimental points of the S/N curve which corresponds to different distribution of initial inclusions in the measuring part of specimen.
Fig. 4: The axial strain as a function of the normed fatigue on the left and evolution of the damage parameter, on the right. can be used to define a damage parameter D as shown on fig. 4. 3. Conclusions
Fig. 4: The axial strain as a function of the normed fatigue on the left and evolution of the damage parameter, on the right. can be used to define a damage parameter D as shown on fig. 4. 3. Conclusions
The evaluation starts with a_ visual investigation. The investigations are shown in fig.1 Surface cracks, and degradation are important indicators of beam condition. Fig. 1: Crack depth determination by thin plate penetration
The evaluation starts with a_ visual investigation. The investigations are shown in fig.1 Surface cracks, and degradation are important indicators of beam condition. Fig. 1: Crack depth determination by thin plate penetration
Fig. 2: Crack depth determination by acoustics (stress wave sensors)
Fig. 2: Crack depth determination by acoustics (stress wave sensors)
Fig. 3: Velocity determination in a lamella
Fig. 3: Velocity determination in a lamella
3. Results In straight and curved = glued laminated timbers (glulam) residual stresses can be significant due to change of climatic conditions. The stress caused by the manufacturing process, the load and the climatic conditions add together. The resulting stress may cause failure. We can find them in practice when the lamellas break or crack parallel to the fibre direction. Our research team uses a stress evaluation method developed at the University of West Hungary [1]. If we know the geometry of the glulam structure, the properties of the lamellas -the thickness, Young’s modulus, the climatic and the manufacturing residual stress can be determined. We also need the initial and final temperature and _ the moisture content values of the lamellas to calculate the climate residual stresses.
3. Results In straight and curved = glued laminated timbers (glulam) residual stresses can be significant due to change of climatic conditions. The stress caused by the manufacturing process, the load and the climatic conditions add together. The resulting stress may cause failure. We can find them in practice when the lamellas break or crack parallel to the fibre direction. Our research team uses a stress evaluation method developed at the University of West Hungary [1]. If we know the geometry of the glulam structure, the properties of the lamellas -the thickness, Young’s modulus, the climatic and the manufacturing residual stress can be determined. We also need the initial and final temperature and _ the moisture content values of the lamellas to calculate the climate residual stresses.
Fig. 7: Residual stresses by the manufacturing process
Fig. 7: Residual stresses by the manufacturing process
Fig. 8: Residual stresses due to change of climate conditions 4. Conclusion
Fig. 8: Residual stresses due to change of climate conditions 4. Conclusion
Fig. 1: Image correlation principle [2] The Q400 measuring system is very easy to handle. Before any measurement the system calibration is necessary to be performed. The Q-400 system has, for a _ successful measurement, a _ calibration procedure incorporated in the measurement and analysis software ISTRA-4D. By the calibration procedure are determined the intrinsic and extrinsic parameters of the cameras. A test plate with a chess model on it is moved in front of the cameras.
Fig. 1: Image correlation principle [2] The Q400 measuring system is very easy to handle. Before any measurement the system calibration is necessary to be performed. The Q-400 system has, for a _ successful measurement, a _ calibration procedure incorporated in the measurement and analysis software ISTRA-4D. By the calibration procedure are determined the intrinsic and extrinsic parameters of the cameras. A test plate with a chess model on it is moved in front of the cameras.
Fig. 2: Experimental set-up The tensile test was conducted according to the EN 10002-1:1990 European Standard for tensile testing of metallic materials at ambient temperature [4]. Five specimens having the same dimensions were tested in the same conditions to check if the measuring results can be reproduced. Instead of using a classical extensometer during the tensile test many images of the specimen were acquired by both cameras of the optical measurement system. The values of the corresponding force at the acquisition time were recorded.
Fig. 2: Experimental set-up The tensile test was conducted according to the EN 10002-1:1990 European Standard for tensile testing of metallic materials at ambient temperature [4]. Five specimens having the same dimensions were tested in the same conditions to check if the measuring results can be reproduced. Instead of using a classical extensometer during the tensile test many images of the specimen were acquired by both cameras of the optical measurement system. The values of the corresponding force at the acquisition time were recorded.
Fig. 3: Engineering stress-strain curve of aluminium Thus for tested commercial aluminium the material constants were Young modulus about 58 N/mm”, Poisson ratio 0,35. The yield stress was about 92 N/mm’ and the ultimate stress about 98 N/mm”.
Fig. 3: Engineering stress-strain curve of aluminium Thus for tested commercial aluminium the material constants were Young modulus about 58 N/mm”, Poisson ratio 0,35. The yield stress was about 92 N/mm’ and the ultimate stress about 98 N/mm”.
Fig.1: Cross section, load The investigation of girders was conducted so that hangers (Fig. 1&2) were suspended from the main girder’s medium nodes. The platforms for loads amounting from the total of 440 kN (40 KN per node) were fastened to the suspenders.
Fig.1: Cross section, load The investigation of girders was conducted so that hangers (Fig. 1&2) were suspended from the main girder’s medium nodes. The platforms for loads amounting from the total of 440 kN (40 KN per node) were fastened to the suspenders.
The investigation was conducted throughout 5 phases (5 girders in a set), and unloading was performed after the completion of each phase. The vertical deflections in each loading phase were measured at 5 characteristic points (Fig. 2) along each girder. Fig.2: The plan of roof, loads, deflections
The investigation was conducted throughout 5 phases (5 girders in a set), and unloading was performed after the completion of each phase. The vertical deflections in each loading phase were measured at 5 characteristic points (Fig. 2) along each girder. Fig.2: The plan of roof, loads, deflections
5. References The diagram (Fig. 6) shows recordings of relative deformations of cables and suspenders. Figure 7 presents deformations of main steel girder no.3. Fig.6: Records of relative deformations of cables and suspenders
5. References The diagram (Fig. 6) shows recordings of relative deformations of cables and suspenders. Figure 7 presents deformations of main steel girder no.3. Fig.6: Records of relative deformations of cables and suspenders
Figure 5 graphically presents experimental and numerical deflections determined in the 3™ phase at one of the characteristic girders no.3. Fig.5: Comparison of experimental and numerical deflections of the girders no.3
Figure 5 graphically presents experimental and numerical deflections determined in the 3™ phase at one of the characteristic girders no.3. Fig.5: Comparison of experimental and numerical deflections of the girders no.3
certain time series signals were registered along with the functions of power spectral density (PSD) determining relevant dynamic parameters. At the same time, during static investigation, the monitoring installed on two characteristic main roof structure girders was activated (Fig. 4). Monitoring includes continuous measuring of the structure's deformations. Fig.4: Points for measuring relative deformations during monitoring
certain time series signals were registered along with the functions of power spectral density (PSD) determining relevant dynamic parameters. At the same time, during static investigation, the monitoring installed on two characteristic main roof structure girders was activated (Fig. 4). Monitoring includes continuous measuring of the structure's deformations. Fig.4: Points for measuring relative deformations during monitoring
Fig.7: Recordings of main girder’s relative deformations (no.3) during monitoring
Fig.7: Recordings of main girder’s relative deformations (no.3) during monitoring
Fig.1: A look at the pedestrian bridge A suspension bridge with 209,5m span connects left and right banks of the Drava river (Fig. 1). The main bearing system consists of cables anchored on either bank over 30,0m high pylons. The deck is suspended by the suspenders from the cables with 4,0m distances. The cables are connected over suspenders and concrete slabs with tendons running beyond the deck and anchored in the pylon blocks. The usable width is 5,0m, and the overall width 6,0m. 2. Investigation and measurement
Fig.1: A look at the pedestrian bridge A suspension bridge with 209,5m span connects left and right banks of the Drava river (Fig. 1). The main bearing system consists of cables anchored on either bank over 30,0m high pylons. The deck is suspended by the suspenders from the cables with 4,0m distances. The cables are connected over suspenders and concrete slabs with tendons running beyond the deck and anchored in the pylon blocks. The usable width is 5,0m, and the overall width 6,0m. 2. Investigation and measurement
Figures 2 and 3 show the comparison of the forces results in cables in downstream and upstream direction. ordinal number of suspenders
Figures 2 and 3 show the comparison of the forces results in cables in downstream and upstream direction. ordinal number of suspenders
[ab.2: Comparison of experimental and natura frequencies for the years 2009 and 1993 4. Conclusions
[ab.2: Comparison of experimental and natura frequencies for the years 2009 and 1993 4. Conclusions
Fig. 3: Forces comparison in suspenders (downstream in 2009, downstream in 1993) Forces in suspenders fell on average by 8% compared to the situation in 1993. With regard to structural analysis the measured forces in suspenders are on average higher by 6%. Largest deviations of measured forces with regard to forces in suspenders from structural analysis are in upstream suspenders no. 59-62. The connection element to the main cables of upstream suspenders 60 and 61 is damaged. The lowest force was measured in the above mentioned suspenders (11,09 and 16,91 kN), and the highest force was measured in adjacent suspenders no. 59 and 62 (69,94 and 67,35 kN). Teaser A weAdante tha wearnedinae At RAGA omarion!
Fig. 3: Forces comparison in suspenders (downstream in 2009, downstream in 1993) Forces in suspenders fell on average by 8% compared to the situation in 1993. With regard to structural analysis the measured forces in suspenders are on average higher by 6%. Largest deviations of measured forces with regard to forces in suspenders from structural analysis are in upstream suspenders no. 59-62. The connection element to the main cables of upstream suspenders 60 and 61 is damaged. The lowest force was measured in the above mentioned suspenders (11,09 and 16,91 kN), and the highest force was measured in adjacent suspenders no. 59 and 62 (69,94 and 67,35 kN). Teaser A weAdante tha wearnedinae At RAGA omarion!
Tab.1: Comparison of experimental and numerical forces in main cables Forces results in cables and their comparison with numerical values from the structural analysis are shown in Table 1. Table 2 shows experimental results of natural frequencies for dynamic investigation of the bridge’s structure.
Tab.1: Comparison of experimental and numerical forces in main cables Forces results in cables and their comparison with numerical values from the structural analysis are shown in Table 1. Table 2 shows experimental results of natural frequencies for dynamic investigation of the bridge’s structure.
SPT tests were performed in special fixture developed for these tests for testing in servo- hydraulic testing machine. Sample deformation was measured by extensometer attached to the testing fixture. All tests were performed at ambient temperature. Samples dimensions are following: diameter 8mm and thickness 0,5mm. Tests records are shown in Fig. 1. Fig. 1: Comparison of SPT records with FEM based results.
SPT tests were performed in special fixture developed for these tests for testing in servo- hydraulic testing machine. Sample deformation was measured by extensometer attached to the testing fixture. All tests were performed at ambient temperature. Samples dimensions are following: diameter 8mm and thickness 0,5mm. Tests records are shown in Fig. 1. Fig. 1: Comparison of SPT records with FEM based results.
3. Small Punch Test Corresponding author: jan.dzugan@comtesfht.cz
3. Small Punch Test Corresponding author: jan.dzugan@comtesfht.cz
Tab. 2: Comparison of tensile properties obtained by SPT and tensile test
Tab. 2: Comparison of tensile properties obtained by SPT and tensile test
The lowest compression strength values were calculated for the regenerates produced in the sheep in (reference) group R. In comparison with the reference group, the strength values determined in the sheep belonging to group A (dFM=Imm) are higher by 23% (regions: CB, PB). Analogical in group B (IFM=2mm) the difference, in comparison with the reference group (R), is even larger and amounts to 40%.
The lowest compression strength values were calculated for the regenerates produced in the sheep in (reference) group R. In comparison with the reference group, the strength values determined in the sheep belonging to group A (dFM=Imm) are higher by 23% (regions: CB, PB). Analogical in group B (IFM=2mm) the difference, in comparison with the reference group (R), is even larger and amounts to 40%.
The engine via gear unit rotates with the pressing disc 1, to which three pressing cones 2 are pressed with pre-stress. Pre-stress is induced by fastening of two nuts on the supporting axis 3, under which a transducer 4 was placed during measurement. Three bending moments
The engine via gear unit rotates with the pressing disc 1, to which three pressing cones 2 are pressed with pre-stress. Pre-stress is induced by fastening of two nuts on the supporting axis 3, under which a transducer 4 was placed during measurement. Three bending moments
Fig. 2: Course of axial force at manual fastening.
Fig. 2: Course of axial force at manual fastening.
Fig. 3: Course of bending moments during fastening.
Fig. 3: Course of bending moments during fastening.
Fig. 5: Course of bending moments at measured places 5. The Figure 4 shows the courses of the axial forces measured by the transducer 4 at normal full output of the machine and at its overload, when the disc holes get clogged. It is obvious that the resulting force at overload is approximately double. The course of the bending moments on the supporting axis at the measured place 5 are shown in the Figure 5. Three strain-gauge half- bridges are along the perimeter of the supporting axis glued in the planes, mutually
Fig. 5: Course of bending moments at measured places 5. The Figure 4 shows the courses of the axial forces measured by the transducer 4 at normal full output of the machine and at its overload, when the disc holes get clogged. It is obvious that the resulting force at overload is approximately double. The course of the bending moments on the supporting axis at the measured place 5 are shown in the Figure 5. Three strain-gauge half- bridges are along the perimeter of the supporting axis glued in the planes, mutually
The granulator is during exploitation sometimes overloaded, when the holes in the pressing disc get clogged. Some courses of the measured values will be shown — at normal full output of the granulator and at its overload.
The granulator is during exploitation sometimes overloaded, when the holes in the pressing disc get clogged. Some courses of the measured values will be shown — at normal full output of the granulator and at its overload.
Fig. 6: Course of bending moment at measured place 6. At the measured place 6 a strain-gauge half- bridge was also glued, enabling evaluation of the courses of bending moments on the axis of one of the pressing cones 2. The course of the evaluated bending moment at the granulator overload is plotted in the Figure 6. Their values also fluctuate heavily.
Fig. 6: Course of bending moment at measured place 6. At the measured place 6 a strain-gauge half- bridge was also glued, enabling evaluation of the courses of bending moments on the axis of one of the pressing cones 2. The course of the evaluated bending moment at the granulator overload is plotted in the Figure 6. Their values also fluctuate heavily.
Fig. 1: The effect of the temperature and electric field on the specific viscosity of ER fluid calculated. Fig. 1 shows the effect of the electric field on the specific viscosity of ER fluid at 20 and 50 °C. The concentration of the ER fluid was 40 w%. The electrode distance was 3 mm. By increasing the electric field intensity, the specific viscosity of the ER fluid increases significantly as seen in the Fig. 1. At 20 °C the flow of the ER fluid was stopped at 0.833 kV/mm field intensity. At 50 °C the field intensity that was needed to stop he flow was 0.7 kV/mm. As increasing the emperature causes the viscosity of the ER fl fluid to decrease, this could be the explanation of the smaller field intensity that is needed to stop the flow.
Fig. 1: The effect of the temperature and electric field on the specific viscosity of ER fluid calculated. Fig. 1 shows the effect of the electric field on the specific viscosity of ER fluid at 20 and 50 °C. The concentration of the ER fluid was 40 w%. The electrode distance was 3 mm. By increasing the electric field intensity, the specific viscosity of the ER fluid increases significantly as seen in the Fig. 1. At 20 °C the flow of the ER fluid was stopped at 0.833 kV/mm field intensity. At 50 °C the field intensity that was needed to stop he flow was 0.7 kV/mm. As increasing the emperature causes the viscosity of the ER fl fluid to decrease, this could be the explanation of the smaller field intensity that is needed to stop the flow.
Fig. 2: The effect of the electric field on the specific viscosity of ER fluid at different electrode distances. The temperature and the electrode distances are
Fig. 2: The effect of the electric field on the specific viscosity of ER fluid at different electrode distances. The temperature and the electrode distances are
Polymers usually can be characterized using more relaxation constants. The number of the elements to be considered is optional. In this paper a three element Maxwell model is used. The first block J; models the inertia of the crankshaft, the second block J; models the inertia of the housing, and the J; is the inertia of the inertia ring. The stiffness and the damping parameters of the damper oil were determined by measurement. In Fig. 3, the mechanical model of a single Maxwell element can be seen. The two coordinates that govern the motion are x; and x». The equation governing the motion of the dashpot is
Polymers usually can be characterized using more relaxation constants. The number of the elements to be considered is optional. In this paper a three element Maxwell model is used. The first block J; models the inertia of the crankshaft, the second block J; models the inertia of the housing, and the J; is the inertia of the inertia ring. The stiffness and the damping parameters of the damper oil were determined by measurement. In Fig. 3, the mechanical model of a single Maxwell element can be seen. The two coordinates that govern the motion are x; and x». The equation governing the motion of the dashpot is
Figure 1: Reduction of all microstructure and S/N-curve parameters to 3 dimensions — Factor Analysis
Figure 1: Reduction of all microstructure and S/N-curve parameters to 3 dimensions — Factor Analysis
Figure 2: Response surface of the calculation error as a function of the loadings F, and F,
Figure 2: Response surface of the calculation error as a function of the loadings F, and F,
Another influence that has to be considered s the operation temperature. Figure 3 shows the Jependency of the relative fatigue stress on this yperation temperature. Figure 3: Relative endurance stress as a function of the operation temperature
Another influence that has to be considered s the operation temperature. Figure 3 shows the Jependency of the relative fatigue stress on this yperation temperature. Figure 3: Relative endurance stress as a function of the operation temperature
Table 1: Comparison of distinct parameters to the experimental fatigue stress
Table 1: Comparison of distinct parameters to the experimental fatigue stress
‘igure 4: Relative estimated stress versus relative experimental stress
‘igure 4: Relative estimated stress versus relative experimental stress
Fig. 1: The fatigue test bar Beside the reference S-N curve, taken for air, three more S-N curves were obtained. They are referred to (1) acidic solution: 50g NaCl + 5g CH;COOH + 945g H,O with pH = 2.7 — 3.0; (11) alkaline solution: 1N water solution Na,CO; and NaHCO, with the ratio 1:1 according to AGA [2] and pH = 9.3; and (iii) water from water main with pH = 6.5. For fatigue tests flat bars (Fig.1) were used.
Fig. 1: The fatigue test bar Beside the reference S-N curve, taken for air, three more S-N curves were obtained. They are referred to (1) acidic solution: 50g NaCl + 5g CH;COOH + 945g H,O with pH = 2.7 — 3.0; (11) alkaline solution: 1N water solution Na,CO; and NaHCO, with the ratio 1:1 according to AGA [2] and pH = 9.3; and (iii) water from water main with pH = 6.5. For fatigue tests flat bars (Fig.1) were used.
The S-N curve for water exhibits a small slope. According to expectation this curve lies above the S-N curves for both solutions but below that for air. While for high cyclic loads he fatigue life for water is much shorter than for air, at low cyclic loads their difference decreases and for the life around 10° cycles the ives are very close to each other. At the life 2 x 10° cycles the corresponding stress (fatigue imit) for water is paradoxically higher than for air. The cause of this behaviour lies in specific properties of water; the course of corrosive actions is predominantly given by admixtures which water always contains.
The S-N curve for water exhibits a small slope. According to expectation this curve lies above the S-N curves for both solutions but below that for air. While for high cyclic loads he fatigue life for water is much shorter than for air, at low cyclic loads their difference decreases and for the life around 10° cycles the ives are very close to each other. At the life 2 x 10° cycles the corresponding stress (fatigue imit) for water is paradoxically higher than for air. The cause of this behaviour lies in specific properties of water; the course of corrosive actions is predominantly given by admixtures which water always contains.
Fig. 3: Variations of the fatigue strength reduction factors on the life
Fig. 3: Variations of the fatigue strength reduction factors on the life
Fig. 1. The force-displacement curve during the loading of the specimen Corresponding author: bgalfi@yahoo.com, janoska@clicknet.ro
Fig. 1. The force-displacement curve during the loading of the specimen Corresponding author: bgalfi@yahoo.com, janoska@clicknet.ro
Fig. 3. The force-displacement curve during the loading and unloading of the specimen unloading phases. In figure 3 is shown a smoothed version of them. On can observe that during the unloading of the specimen, the effect/the influence of the pre-compressed cells, which have residual deformations, make that the unloading curve is located over the loading one (unusual thing at metallic specimens).
Fig. 3. The force-displacement curve during the loading and unloading of the specimen unloading phases. In figure 3 is shown a smoothed version of them. On can observe that during the unloading of the specimen, the effect/the influence of the pre-compressed cells, which have residual deformations, make that the unloading curve is located over the loading one (unusual thing at metallic specimens).
Fig.1: Testing rig of crankshafts at fatigue rotating bending Bending fatigue testing of crankshafts was performed in a fatigue testing rig (Fig. 1).
Fig.1: Testing rig of crankshafts at fatigue rotating bending Bending fatigue testing of crankshafts was performed in a fatigue testing rig (Fig. 1).
Tab 2. Failure probability for nonitrided crankshafts for Sy=250 N/mm?
Tab 2. Failure probability for nonitrided crankshafts for Sy=250 N/mm?
Fig. 2: S-N curve with overall scatter region for nonitrided crankshafts
Fig. 2: S-N curve with overall scatter region for nonitrided crankshafts
Fig. 3: S-N curve with overall scatter region for nitrided crankshafts
Fig. 3: S-N curve with overall scatter region for nitrided crankshafts
For every damage level, RVAC is calculated from equation (1). All numerical results are obtained from routines developed in the Matlab package, and shown on Fig.1. It can be seen that RVAC gives information about the relative extend of the damage. Fig. 1: RVAC value for four natural frequencies of beam and five damage levels
For every damage level, RVAC is calculated from equation (1). All numerical results are obtained from routines developed in the Matlab package, and shown on Fig.1. It can be seen that RVAC gives information about the relative extend of the damage. Fig. 1: RVAC value for four natural frequencies of beam and five damage levels
is repeated for the four level of damage: d=1 is undamage beam, d=2 coresponds to crack of 1 mm depth, d=3 is crack of 2 mm depth, d=4 is crack of 4 mm depth. The first four natural frequencies for different damage levels are given in Tab.2. Fig.2. shows overlaid FRFs measured at node 8 for four damage levels, and Fig.3. shows RVACs_ for experimentaly obtained data.
is repeated for the four level of damage: d=1 is undamage beam, d=2 coresponds to crack of 1 mm depth, d=3 is crack of 2 mm depth, d=4 is crack of 4 mm depth. The first four natural frequencies for different damage levels are given in Tab.2. Fig.2. shows overlaid FRFs measured at node 8 for four damage levels, and Fig.3. shows RVACs_ for experimentaly obtained data.
Tab. 2: Natural frequencies for different damage levels, experimentally obtained
Tab. 2: Natural frequencies for different damage levels, experimentally obtained
Fig. 3: RVAC value for four natural frequencies of beam and four damage levels Fig. 2: Overlaid FRFs measured at node 8 for four damage level
Fig. 3: RVAC value for four natural frequencies of beam and four damage levels Fig. 2: Overlaid FRFs measured at node 8 for four damage level
Fig. 1 - SEM micrograph showing Mat, Roving and Volumat layers.
Fig. 1 - SEM micrograph showing Mat, Roving and Volumat layers.
Fig. 2. Reconstruction of a 2D cross-section of a cracked specimen.
Fig. 2. Reconstruction of a 2D cross-section of a cracked specimen.
Fig. 1: Test set-up for surface DMA tests. The experimental set-up of the ring-on-disc (RoD) test set-up on the dynamic testing machine is shown in fig. 1. The same specimen geometry and the surface quality was used as previously in classical friction and wear tests. During these movement of the torsiona normal load and rotationa and a represen plotted in fig. 3. not provide su However, fficient in stick-slip behaviour of the Hence, a nove method implemented on an elec machine. The rotational drive has either a monotonic or an oscillating movement during ests a continuous rotational drive with varying speed was realized ative result of these tests is this type of test does formation about the elastomer specimen. was developed and trodynamical testing
Fig. 1: Test set-up for surface DMA tests. The experimental set-up of the ring-on-disc (RoD) test set-up on the dynamic testing machine is shown in fig. 1. The same specimen geometry and the surface quality was used as previously in classical friction and wear tests. During these movement of the torsiona normal load and rotationa and a represen plotted in fig. 3. not provide su However, fficient in stick-slip behaviour of the Hence, a nove method implemented on an elec machine. The rotational drive has either a monotonic or an oscillating movement during ests a continuous rotational drive with varying speed was realized ative result of these tests is this type of test does formation about the elastomer specimen. was developed and trodynamical testing
Fig. 3: Results of the friction tests using RoD test set-up. Fig. 2: Test fixture along with the specimen and counterpart for surface DMA tests.
Fig. 3: Results of the friction tests using RoD test set-up. Fig. 2: Test fixture along with the specimen and counterpart for surface DMA tests.
Fig. 4: Monotonic torque-rotation curves at various normal loads and for various loading rates. Torque-rotation (M-@) curves at various normal loads at low loading rate under monotonic loading are shown in fig. 4a for an unfilled TPU specimen.
Fig. 4: Monotonic torque-rotation curves at various normal loads and for various loading rates. Torque-rotation (M-@) curves at various normal loads at low loading rate under monotonic loading are shown in fig. 4a for an unfilled TPU specimen.
Fig. 5: Cyclic torque-rotation hysteretic curves at a normal load of 1.5 MPa.
Fig. 5: Cyclic torque-rotation hysteretic curves at a normal load of 1.5 MPa.
The horizontal measures of the simulation model were 50m x 16m. An additional requirement was that a one meter difference in height can vertically be measured at every point of the co- ordinate system. Fig. 1: Total view of the model of the Danube to the east of Vienna
The horizontal measures of the simulation model were 50m x 16m. An additional requirement was that a one meter difference in height can vertically be measured at every point of the co- ordinate system. Fig. 1: Total view of the model of the Danube to the east of Vienna
Several triangulating laser measuring probes (triangulation methods) by Festo are used for length measuring systems [1]. Fig. 2: Measuring bridge with the measuring olatform and five mounted laser triangulation sensors
Several triangulating laser measuring probes (triangulation methods) by Festo are used for length measuring systems [1]. Fig. 2: Measuring bridge with the measuring olatform and five mounted laser triangulation sensors
Fig. 1: Telescopic cover - Direction of wiper friction and resistance forces (F, and F,) Machine tool manufacturers begin to focus on optimizing peripherals such as telescopic covers [1]. Passive resistance of covers and its sealing wipers in particular becomes more significant factor of drive power dimensioning. 2. Sealing wiper
Fig. 1: Telescopic cover - Direction of wiper friction and resistance forces (F, and F,) Machine tool manufacturers begin to focus on optimizing peripherals such as telescopic covers [1]. Passive resistance of covers and its sealing wipers in particular becomes more significant factor of drive power dimensioning. 2. Sealing wiper
Fig. 2: Comparison of experimental and modelled stiffness characteristics Physical behaviour of sealing wiper ha been examined by a mathematical model and ; has been verified by an experiment [2]. It stiffness characteristic is bilinear respecting tw contact zones of the wiper (compliant wiper li and stiffer sealing plane).
Fig. 2: Comparison of experimental and modelled stiffness characteristics Physical behaviour of sealing wiper ha been examined by a mathematical model and ; has been verified by an experiment [2]. It stiffness characteristic is bilinear respecting tw contact zones of the wiper (compliant wiper li and stiffer sealing plane).
Fig. 6: Normal force curve along wiper length; all wipers in contact with segments This model also shows whether the wiper is in contact with the segment below to assure sealing functionality. If the normal force of any segment reaches zero, it means that there is no preload of wiper. Zero preload represents gap between wiper and the segment. This can happen in case of large cover and it must be prevented by cover modification [3].
Fig. 6: Normal force curve along wiper length; all wipers in contact with segments This model also shows whether the wiper is in contact with the segment below to assure sealing functionality. If the normal force of any segment reaches zero, it means that there is no preload of wiper. Zero preload represents gap between wiper and the segment. This can happen in case of large cover and it must be prevented by cover modification [3].
Fig. 7: Frictional force during cover extension Figure 7 shows 15 % difference of cover sealant frictional force during cover extension. In case of two covers usually mounted onto movable axis of a machine tool, this difference is lower (5 %). This difference is caused by change of relative distance of wipers that provide support of compliant segments.
Fig. 7: Frictional force during cover extension Figure 7 shows 15 % difference of cover sealant frictional force during cover extension. In case of two covers usually mounted onto movable axis of a machine tool, this difference is lower (5 %). This difference is caused by change of relative distance of wipers that provide support of compliant segments.
Fig. 1 Cross section of bonding part Table 1 Content of conductive filler printed wire boards with the conductive adhesive resin. The material is FR-4. The copper foil is coated on the board in the diagonal direction of the board. The change of electrical conductivity during loading tests is measured through this copper foil. The conductive adhesive resin is put on the center point circle with diameter 0.8mm of the copper foil. Then the two boards are adhered by overlapping each other. The specimen is cured for one hour at 130 centigrade under pressure 5MPa. The rod with the diameter of 0.28mm is put between two boards to keep the constant distance of the two boards. Figure 1 shows the cross section of the adhesively bonded part.
Fig. 1 Cross section of bonding part Table 1 Content of conductive filler printed wire boards with the conductive adhesive resin. The material is FR-4. The copper foil is coated on the board in the diagonal direction of the board. The change of electrical conductivity during loading tests is measured through this copper foil. The conductive adhesive resin is put on the center point circle with diameter 0.8mm of the copper foil. Then the two boards are adhered by overlapping each other. The specimen is cured for one hour at 130 centigrade under pressure 5MPa. The rod with the diameter of 0.28mm is put between two boards to keep the constant distance of the two boards. Figure 1 shows the cross section of the adhesively bonded part.
Fig. 3 Combined strength for mixed filler content Fig. 2 Tensile strength for different filler contents
Fig. 3 Combined strength for mixed filler content Fig. 2 Tensile strength for different filler contents
Fig. 1: Positioning system of portal type
Fig. 1: Positioning system of portal type
3. Experimental Results
3. Experimental Results
Fig. 5 shows the proposed screen layout or the user interface. When the scanner is started this mode is the first to be displayed. It provides a button menu for selection of all menus, buttons for selecting manual or automatic referencing (in sequence Z,X,Y,B), start and stop buttons for referencing, status visualization of the servo-system and the laser head, visualization of the current coordinates and buttons for manual positioning along all axes (the latter are needed in case the system is in a location unsuitable for starting the Referencing mode).
Fig. 5 shows the proposed screen layout or the user interface. When the scanner is started this mode is the first to be displayed. It provides a button menu for selection of all menus, buttons for selecting manual or automatic referencing (in sequence Z,X,Y,B), start and stop buttons for referencing, status visualization of the servo-system and the laser head, visualization of the current coordinates and buttons for manual positioning along all axes (the latter are needed in case the system is in a location unsuitable for starting the Referencing mode).
Fig. 4: General view of the scanner
Fig. 4: General view of the scanner
The 50 MPa equipment designed to stretch aluminum plates is made of two jaws in which the ends of the plates are fixed. Each jaw has eight lamellae, drilled and cross-cut at the lower side. The aluminum plate is fixed in the lamellae through a system of clamping dies made of two flattening beams and two wedges (Fig. 1). Fig. 1: The fixing system of the aluminum plate For a correct evaluation of the performances and the technological parameters of the equipment in service, an experimental study was undertaken for the model of a lamella, using the photoelastic technique. The obtained results were compared with numerical results, yielding from Finite Element analyses.
The 50 MPa equipment designed to stretch aluminum plates is made of two jaws in which the ends of the plates are fixed. Each jaw has eight lamellae, drilled and cross-cut at the lower side. The aluminum plate is fixed in the lamellae through a system of clamping dies made of two flattening beams and two wedges (Fig. 1). Fig. 1: The fixing system of the aluminum plate For a correct evaluation of the performances and the technological parameters of the equipment in service, an experimental study was undertaken for the model of a lamella, using the photoelastic technique. The obtained results were compared with numerical results, yielding from Finite Element analyses.
Fig. 2: The considered positions of the wedges thickness of 9.5 mm. The aluminum plate was considered wedged using the wedges and flattening beams. That is why the whole assembly plate — wedges was modeled as a single wedge made also of a 9.5 mm thick Plexiglas plate. The photoelastic measurements were undertaken for three different positions of the wedges, found often in the real process of stretching (Fig. 5).
Fig. 2: The considered positions of the wedges thickness of 9.5 mm. The aluminum plate was considered wedged using the wedges and flattening beams. That is why the whole assembly plate — wedges was modeled as a single wedge made also of a 9.5 mm thick Plexiglas plate. The photoelastic measurements were undertaken for three different positions of the wedges, found often in the real process of stretching (Fig. 5).
The isoclines and the isochromatic fringes (Fig. 3) were recorded corresponding to the three considered positions of the wedges. Fig. 3: The isochromatic fringe field (Case 1)
The isoclines and the isochromatic fringes (Fig. 3) were recorded corresponding to the three considered positions of the wedges. Fig. 3: The isochromatic fringe field (Case 1)
With the data obtained from the above calculations, the variation curves of the principal stresses on the contour of the hole were plotted (Fig. 4).
With the data obtained from the above calculations, the variation curves of the principal stresses on the contour of the hole were plotted (Fig. 4).
Fig. 5: Comparative plot of the principal stresses (Case 1).
Fig. 5: Comparative plot of the principal stresses (Case 1).
Wood exhibits a hierarchical structure and is composed of fibers which can be represented as hollow tubes oriented in stem direction (see Fig. 1(a)). The fibers are built up of a cell wall material consisting of stiff cellulose microfibrils which are embedded in a soft polymer matrix. The S2 layer of the cell wall occupies approximately 80 % of the cell wall and mainly contributes to the load bearing capacity of wood. Within the S2 layer, the stiff microfibrils are inclined to the longitudinal cell axis by the so. called mircofibril angle, giving an approximately transversely isotropic material. Fig. 1: (a) Wood fiber consisting of different cell wall layers and (b) conical indentation in S2 layer of wood cell wall: orientation of the material axis and indentation direction. The mechanical properties of the S2 layer can be measured by tension tests on single wood fibers or by means of nanoindentation. As reported by several authors (see, e.g., [1]), the measured indentation modulus in longitudinal direction is considerably smaller than the expected Young’s modulus in the same direction. This can be explained by the small
Wood exhibits a hierarchical structure and is composed of fibers which can be represented as hollow tubes oriented in stem direction (see Fig. 1(a)). The fibers are built up of a cell wall material consisting of stiff cellulose microfibrils which are embedded in a soft polymer matrix. The S2 layer of the cell wall occupies approximately 80 % of the cell wall and mainly contributes to the load bearing capacity of wood. Within the S2 layer, the stiff microfibrils are inclined to the longitudinal cell axis by the so. called mircofibril angle, giving an approximately transversely isotropic material. Fig. 1: (a) Wood fiber consisting of different cell wall layers and (b) conical indentation in S2 layer of wood cell wall: orientation of the material axis and indentation direction. The mechanical properties of the S2 layer can be measured by tension tests on single wood fibers or by means of nanoindentation. As reported by several authors (see, e.g., [1]), the measured indentation modulus in longitudinal direction is considerably smaller than the expected Young’s modulus in the same direction. This can be explained by the small
Combining the micromechanical model with the model for the indentation modulus allows to study the influence of MFA and moisture content on the indentation modulus of wood cell walls. Figure 2(b) shows the decrease of the predicted indentation modulus with increasing MFA for a typical chemical composition of spruce and varying moisture content. Fig. 3: Predicted variation of indentation modulus as a function of microfibril angle and moisture content.
Combining the micromechanical model with the model for the indentation modulus allows to study the influence of MFA and moisture content on the indentation modulus of wood cell walls. Figure 2(b) shows the decrease of the predicted indentation modulus with increasing MFA for a typical chemical composition of spruce and varying moisture content. Fig. 3: Predicted variation of indentation modulus as a function of microfibril angle and moisture content.
Fig. 2: Comparison of predicted and measured [6] indentation modulus.
Fig. 2: Comparison of predicted and measured [6] indentation modulus.
Flexible polyurethane foams are commonly used materials in automotive applications, especially for internal cockpit parts and seats. During accidental impact passenger’s head has to be stopped by the headrest (Fig.1). As it is showed in Fig.2, padding material of a headrest has a_ significant influence on a_ head deceleration [3]. Mechanical properties of two material systems (polyurethane foam) with a certain range of densities and components proportions have been studied. Dynamic impact tests have been carried out. Results are presented below. Analytical constitutive model of compression has been proposed, which assumes that density, components proportion and strain rate are separable functions [1, 4]. The model has been verified by experimental results of static tests [4]. Impact tests have been conducted due to two objectives: to investigate impact behaviour of examined material and to validate numerical solution based on the method of lump mass [2].
Flexible polyurethane foams are commonly used materials in automotive applications, especially for internal cockpit parts and seats. During accidental impact passenger’s head has to be stopped by the headrest (Fig.1). As it is showed in Fig.2, padding material of a headrest has a_ significant influence on a_ head deceleration [3]. Mechanical properties of two material systems (polyurethane foam) with a certain range of densities and components proportions have been studied. Dynamic impact tests have been carried out. Results are presented below. Analytical constitutive model of compression has been proposed, which assumes that density, components proportion and strain rate are separable functions [1, 4]. The model has been verified by experimental results of static tests [4]. Impact tests have been conducted due to two objectives: to investigate impact behaviour of examined material and to validate numerical solution based on the method of lump mass [2].
Fig. 2: Head deceleration for three different foam materials of a headrest [3]
Fig. 2: Head deceleration for three different foam materials of a headrest [3]
Impact tests were carried out on the specia experimental rig shown in Fig.7. Impactor falls from a certain height and hits a specimen. Velocity of impactor is measured by optica device just before contact with a specimen. Deceleration of the impactor during foam deformation is measured by accelerometer and
Impact tests were carried out on the specia experimental rig shown in Fig.7. Impactor falls from a certain height and hits a specimen. Velocity of impactor is measured by optica device just before contact with a specimen. Deceleration of the impactor during foam deformation is measured by accelerometer and
Fig. 4: Sample no.1 - Various impact velocities. recorded by a computer. Results of impact tests are presented at Fig. 4,5,6.
Fig. 4: Sample no.1 - Various impact velocities. recorded by a computer. Results of impact tests are presented at Fig. 4,5,6.
fig. 5: Samples no.1 — 4 (various components proportions) — Impact velocity ~1,2 m/s. Fig. 6: Samples no. 1 — 4 (various components proportions) — Impact velocity ~3,7 m/s 4. References
fig. 5: Samples no.1 — 4 (various components proportions) — Impact velocity ~1,2 m/s. Fig. 6: Samples no. 1 — 4 (various components proportions) — Impact velocity ~3,7 m/s 4. References
Fig. 7: Impact test device. 1 - foam specimen, 2 - impactor, 3 - impactor guides, 4 - speed measure device, 5 - accelerometer.
Fig. 7: Impact test device. 1 - foam specimen, 2 - impactor, 3 - impactor guides, 4 - speed measure device, 5 - accelerometer.
Fig. 1. Selected measuring locations: measuring spot I Lamellae of bucket wheel boom; measuring spot 2 — Lower carrier of counter weight structure; measuring spot 3 — Upper carrier of counter weight structure
Fig. 1. Selected measuring locations: measuring spot I Lamellae of bucket wheel boom; measuring spot 2 — Lower carrier of counter weight structure; measuring spot 3 — Upper carrier of counter weight structure
Force accession measurement was performed at described points at extremely high ambient temperature, in August 2007. Placement of strain gauge at lamellae was done when excavator was under load. First measurement, performed during excavation, provided two signals related to technological operation of excavator. Force accession (stress) diagram in time domain, shown at Fig. 2, for all three measuring spots, represents first signal of stress during block excavation and super- structure slewing to the left. Fig. 2. Stress diagram during excavation, in time domain — first signal (excavation, slewing to the left) Highest stress accession, of 24.6 N/mm’, was recorded at lower carrier of counter weight. Stress accession at boom's lamellae is max. 17.8 N/mm”, while at the stress accession at upper carrier of the counter weight was max. 12.5 N/mm’. Stress at lamellae is constant throughout the excavation, while the stress at the counter weight carriers varies — it is larger within the lower carrier at the beginning of the process and as the process progress it builds up
Force accession measurement was performed at described points at extremely high ambient temperature, in August 2007. Placement of strain gauge at lamellae was done when excavator was under load. First measurement, performed during excavation, provided two signals related to technological operation of excavator. Force accession (stress) diagram in time domain, shown at Fig. 2, for all three measuring spots, represents first signal of stress during block excavation and super- structure slewing to the left. Fig. 2. Stress diagram during excavation, in time domain — first signal (excavation, slewing to the left) Highest stress accession, of 24.6 N/mm’, was recorded at lower carrier of counter weight. Stress accession at boom's lamellae is max. 17.8 N/mm”, while at the stress accession at upper carrier of the counter weight was max. 12.5 N/mm’. Stress at lamellae is constant throughout the excavation, while the stress at the counter weight carriers varies — it is larger within the lower carrier at the beginning of the process and as the process progress it builds up
Force accession (stress) diagram in time domain is shown at Fig. 3, for second signal of stress during block excavation and super- structure slewing to the right. Fig. 3. Stress diagram during excavation, in time domain — second signal (excavation, slewing to the right)
Force accession (stress) diagram in time domain is shown at Fig. 3, for second signal of stress during block excavation and super- structure slewing to the right. Fig. 3. Stress diagram during excavation, in time domain — second signal (excavation, slewing to the right)
Force (stress) accession, for all three measuring spots during transportation of the excavator, but not in excavation, is shown at Fig. 4.
Force (stress) accession, for all three measuring spots during transportation of the excavator, but not in excavation, is shown at Fig. 4.
transmitting (T) and receiving (R) transducers along with stepper motors (M) and _ their controllers. The program (in LabView) allows control of kinematics of the reflectometer and automatic data acquisition. The program for signal analysis (in Matlab) performs averaging, spectral analysis, calculation of reflection coefficient and its diffraction correction. The diffraction correction is based on angular spectrum method. The reference signal for calculation of reflection coefficient is taken for face to face position of transducers. The experimental system works both in air (using Ultran transducers) and in water (with Panametrics immersion transducers).
transmitting (T) and receiving (R) transducers along with stepper motors (M) and _ their controllers. The program (in LabView) allows control of kinematics of the reflectometer and automatic data acquisition. The program for signal analysis (in Matlab) performs averaging, spectral analysis, calculation of reflection coefficient and its diffraction correction. The diffraction correction is based on angular spectrum method. The reference signal for calculation of reflection coefficient is taken for face to face position of transducers. The experimental system works both in air (using Ultran transducers) and in water (with Panametrics immersion transducers).
Fig. 2. Reflection coefficient for (a) water/water saturated porous sintered glass, 0.5 MHz, (b) air/air saturated porous glass system, 0.2 MHz. Results of two tests are shown, glass with 260 um average diameter of grains.
Fig. 2. Reflection coefficient for (a) water/water saturated porous sintered glass, 0.5 MHz, (b) air/air saturated porous glass system, 0.2 MHz. Results of two tests are shown, glass with 260 um average diameter of grains.
Fig. 3. Calculated reflection coefficients for (a) water/water saturated porous sintered glass, 0.5 MHz, (b) air/air saturated porous glass system, 0.2 MHz. In the second case the predictions of single and two phase models are shown.
Fig. 3. Calculated reflection coefficients for (a) water/water saturated porous sintered glass, 0.5 MHz, (b) air/air saturated porous glass system, 0.2 MHz. In the second case the predictions of single and two phase models are shown.
The specimens were made from one composite with 45% volume fraction of Terfenol-D powder, which was divided in two, and afterward cross section perpendicular and rectangular to polarization lines were made. The specimens are presented in figure 1.
The specimens were made from one composite with 45% volume fraction of Terfenol-D powder, which was divided in two, and afterward cross section perpendicular and rectangular to polarization lines were made. The specimens are presented in figure 1.
‘ig. 1. Comparison of magnetostriction for solid Terfenol-D and composite material. investigated composite specimen reached 700 ppm in comparison to Terfenol-D 1500 ppm at H=180kA/m (figure 2).
‘ig. 1. Comparison of magnetostriction for solid Terfenol-D and composite material. investigated composite specimen reached 700 ppm in comparison to Terfenol-D 1500 ppm at H=180kA/m (figure 2).
Fig. 1. Sensor position regard to the specimen during investigations of Villari effect. Fig. 1. Comparison of different applied forces on changes in magnetic response of the specimen.
Fig. 1. Sensor position regard to the specimen during investigations of Villari effect. Fig. 1. Comparison of different applied forces on changes in magnetic response of the specimen.
Fig. 1. Comparison of different position of sensor on changes in magnetic response of the specimen at the same value of applied force F=550[N].
Fig. 1. Comparison of different position of sensor on changes in magnetic response of the specimen at the same value of applied force F=550[N].
Figure 5 shows changes in magnetic response of the investigated specimen depended on different position of sensor along the specimen as it is showed in figure 3.
Figure 5 shows changes in magnetic response of the investigated specimen depended on different position of sensor along the specimen as it is showed in figure 3.
magnetic response of the specimen rise together with increasing of the force, but shape of the loop did not change.
magnetic response of the specimen rise together with increasing of the force, but shape of the loop did not change.
to enable registration Of mechanical signals (stress o(t) and strain e(t)) and magnetic (the magnetic field strength H(t)). For measurement of the magnetic field strength the experimenters used a unique setup developed at the Institute of Material Science and Applied Mechanics by one of the co-authors of the present work. In this setup four Philips KMZ _ 10B magnetoresistors were used as sensors. They were placed in line alongside the specimen’s section to be measured. Fig. 1. Measuring stand: 1 — hydraulic pulsator MTS 810, 2 — setup for magnetic field measurement, 3 — extensometer, 4 — magnetoresistors, 5 — specimen.
to enable registration Of mechanical signals (stress o(t) and strain e(t)) and magnetic (the magnetic field strength H(t)). For measurement of the magnetic field strength the experimenters used a unique setup developed at the Institute of Material Science and Applied Mechanics by one of the co-authors of the present work. In this setup four Philips KMZ _ 10B magnetoresistors were used as sensors. They were placed in line alongside the specimen’s section to be measured. Fig. 1. Measuring stand: 1 — hydraulic pulsator MTS 810, 2 — setup for magnetic field measurement, 3 — extensometer, 4 — magnetoresistors, 5 — specimen.
Figure 2 presents the spectrum of the stress signal for the deformation threshold ¢, = 0.0035 mm/mm. As we can see the initial stress value equaled o, = 250 MPa and in the course of the fatigue process increased up to the maximum value o, = 420 MPa. Increasing of stress during fatigue process testify to the material strengthening. This strengthening is directly connected with the increase in the a’ martensite content in the matrix of y austenitic.The stress increased up to the moment when first local fractures of the specimen occurred. It was assumed that the specimen fracture took place at the decrease in force value of 1%. Fig. 2. Spectrum of strain signal.
Figure 2 presents the spectrum of the stress signal for the deformation threshold ¢, = 0.0035 mm/mm. As we can see the initial stress value equaled o, = 250 MPa and in the course of the fatigue process increased up to the maximum value o, = 420 MPa. Increasing of stress during fatigue process testify to the material strengthening. This strengthening is directly connected with the increase in the a’ martensite content in the matrix of y austenitic.The stress increased up to the moment when first local fractures of the specimen occurred. It was assumed that the specimen fracture took place at the decrease in force value of 1%. Fig. 2. Spectrum of strain signal.
Fig. 1. Examples of the use of the magnetic field stream disturbance for detection of changes on the ferromagnetics surface: laser engraving A), crack on the disc B) magnetopolygraphy C).
Fig. 1. Examples of the use of the magnetic field stream disturbance for detection of changes on the ferromagnetics surface: laser engraving A), crack on the disc B) magnetopolygraphy C).
Fig. 2. Window and main features of Maglab software.
Fig. 2. Window and main features of Maglab software.
Fig. 1: Pitting Growth Diagram.
Fig. 1: Pitting Growth Diagram.
Fig. 2: Flank damane of case-hardened gear (A) and gear with WC layer (B) manufactured practices (reference gearing), verified the accuracy of the methodology of design and strength check of gears. Experimentally was achieved the calculation of gearing lifetime. A characteristic phenomenon’ was - significant variance of values of life among each gearing.
Fig. 2: Flank damane of case-hardened gear (A) and gear with WC layer (B) manufactured practices (reference gearing), verified the accuracy of the methodology of design and strength check of gears. Experimentally was achieved the calculation of gearing lifetime. A characteristic phenomenon’ was - significant variance of values of life among each gearing.
Fig. 3: Numerical model of crack propagation
Fig. 3: Numerical model of crack propagation
Fig. 4: Metallographic section of tooth Geometry of dimples and pitting cracks at different stages were studied on metallographic sections and cuts made in the most damaged teeth. Cuts were conducted in order to go through centre of macro-dimple. Acquired images were processed using of programme LuciaNet.
Fig. 4: Metallographic section of tooth Geometry of dimples and pitting cracks at different stages were studied on metallographic sections and cuts made in the most damaged teeth. Cuts were conducted in order to go through centre of macro-dimple. Acquired images were processed using of programme LuciaNet.
0%, 12%, 26%. The applied acoustic emission (AE) apparatus was a Defectophone (KFKI Hungary) with two logarithmic amplifiers and two wideband piezoelectric-transducers type SE1000-H. The examined frequency domain was 20-250 kHz. The applied threshold was 22 uV. The examination of 20-100 kHz range seemed to be essential due to the preliminary analysis, which showed ca. 30% of the total events are in this range (Kannar 2004). The coupling material was silicon grease. The characteristic fracture Results
0%, 12%, 26%. The applied acoustic emission (AE) apparatus was a Defectophone (KFKI Hungary) with two logarithmic amplifiers and two wideband piezoelectric-transducers type SE1000-H. The examined frequency domain was 20-250 kHz. The applied threshold was 22 uV. The examination of 20-100 kHz range seemed to be essential due to the preliminary analysis, which showed ca. 30% of the total events are in this range (Kannar 2004). The coupling material was silicon grease. The characteristic fracture Results
the full volume of the stressed specimen, which progress randomly towards one another (Bariska 1985). Additionally, the advancement of micro- damage processes is a function of the particular specimen's biological and anatomical structure.
the full volume of the stressed specimen, which progress randomly towards one another (Bariska 1985). Additionally, the advancement of micro- damage processes is a function of the particular specimen's biological and anatomical structure.
Fig.3. Tension fracture surface of spruce at 0% MC after tensile test
Fig.3. Tension fracture surface of spruce at 0% MC after tensile test
This indirect technology is simple and exact. Even so only a few similar measuring has been found in the bibliography. This method usually was referred like theoretical possibility. To make the test we need for a prime mover to material search and for a machine to determine the deflection. We can use a new instrument to determine the deflection. It is _ the videoextensometer, which give the deflection through optically and computationally way. The experimental arrangement of the simple tension tests are shown in fig. 1. Fig. 1: Picture of videoextensometer during measure 2. Experimental Results
This indirect technology is simple and exact. Even so only a few similar measuring has been found in the bibliography. This method usually was referred like theoretical possibility. To make the test we need for a prime mover to material search and for a machine to determine the deflection. We can use a new instrument to determine the deflection. It is _ the videoextensometer, which give the deflection through optically and computationally way. The experimental arrangement of the simple tension tests are shown in fig. 1. Fig. 1: Picture of videoextensometer during measure 2. Experimental Results
Fig. 2: Specific strains by simple tension Tab. 1. The experimental results of the simple tension
Fig. 2: Specific strains by simple tension Tab. 1. The experimental results of the simple tension
Fig. 1. Different mmC with total chip area A,=10mm? Fig. 2. Different mmC with total chip area A,=50mm?
Fig. 1. Different mmC with total chip area A,=10mm? Fig. 2. Different mmC with total chip area A,=50mm?
of homogenization annealing at temperature T = 415 °C, holding time at this temperature for 3 hours and consequential slowly cooling in the furnace. The goal of the heat treatment was removing the original dendritic structure and achieve of polyhedral grains. In Fig. 1 two damping curves marked as the 1" and the 2" measurement are compared. The measurements were performed only in one test bar. It can be seen that the damping does not considerably depend on the temperature up to 200°C for both measurements. However significant damping maximum was detected at 150 °C with other considerable smaller damping peaks in his temperature interval. Concretely the damping value at the temperature 150 °C was 1.75x10* at the 1" measurement and 1.8x10“ for the 2"" measurement. As can be seen from both damping curves the damping further increases from 200 °C with increasing of the emperature. It can be further seen from Fig. 1 hat the 2" measurement has damping phone (i.e. zone without phase transformation) moved o higher value than for the 1" measurement. Higher damping value for 2" measurement can be probably explained by partial annealing of est bar during 1" damping measurement Fig. 1 Damping curves for non-heat treated AZ31
of homogenization annealing at temperature T = 415 °C, holding time at this temperature for 3 hours and consequential slowly cooling in the furnace. The goal of the heat treatment was removing the original dendritic structure and achieve of polyhedral grains. In Fig. 1 two damping curves marked as the 1" and the 2" measurement are compared. The measurements were performed only in one test bar. It can be seen that the damping does not considerably depend on the temperature up to 200°C for both measurements. However significant damping maximum was detected at 150 °C with other considerable smaller damping peaks in his temperature interval. Concretely the damping value at the temperature 150 °C was 1.75x10* at the 1" measurement and 1.8x10“ for the 2"" measurement. As can be seen from both damping curves the damping further increases from 200 °C with increasing of the emperature. It can be further seen from Fig. 1 hat the 2" measurement has damping phone (i.e. zone without phase transformation) moved o higher value than for the 1" measurement. Higher damping value for 2" measurement can be probably explained by partial annealing of est bar during 1" damping measurement Fig. 1 Damping curves for non-heat treated AZ31
Fig. 2 Damping curves for heat treated AZ31 alloy. The damping curves for annealed alloy are shown in Fig.2. A couple of damping measurements after heat treatment was performed in same test bar as in the case of original state of Mg alloy (without heat treatment) and is marked as the 3" and 4" measurement. These results are compared ogether with damping curves for original state (® and 2" measuremen ). It can be seen that the heat treatment considerably influenced the character of damping curves, namely by occurrence of two damping maximums at the emperatures 173°C and 230°C. The damping value was 2.8x10~ for the 3” measurement, and 3.1x10* for the 4" measurement at 173 °C and approximately 4.5x10“ for both measurements at 230 °C. From Fig. 2 can be seen that maximum damping values measured for heat treated alloy are almost three times higher than that for non- heat treated alloy. That is why the maximum peaks for original state of alloy nearly disappeared. Measured damping maximums can be explained by relaxation processes took place in material for both original and heat treated state of AZ31 alloy. The relaxation processes can be connected with dislocation motion and their interaction with vacancies, impurities, secondary phases or grain boundaries [6]. For lower temperatures (to 120°C) the internal damping process is probably a result of dislocation motion in basal planes whereas at higher temperatures grain boundary sliding plays dominant role.
Fig. 2 Damping curves for heat treated AZ31 alloy. The damping curves for annealed alloy are shown in Fig.2. A couple of damping measurements after heat treatment was performed in same test bar as in the case of original state of Mg alloy (without heat treatment) and is marked as the 3" and 4" measurement. These results are compared ogether with damping curves for original state (® and 2" measuremen ). It can be seen that the heat treatment considerably influenced the character of damping curves, namely by occurrence of two damping maximums at the emperatures 173°C and 230°C. The damping value was 2.8x10~ for the 3” measurement, and 3.1x10* for the 4" measurement at 173 °C and approximately 4.5x10“ for both measurements at 230 °C. From Fig. 2 can be seen that maximum damping values measured for heat treated alloy are almost three times higher than that for non- heat treated alloy. That is why the maximum peaks for original state of alloy nearly disappeared. Measured damping maximums can be explained by relaxation processes took place in material for both original and heat treated state of AZ31 alloy. The relaxation processes can be connected with dislocation motion and their interaction with vacancies, impurities, secondary phases or grain boundaries [6]. For lower temperatures (to 120°C) the internal damping process is probably a result of dislocation motion in basal planes whereas at higher temperatures grain boundary sliding plays dominant role.
The response in the form of ratio of absolute value of acceleration at top plate and base plate of the model over the ratio of excitation frequency to its first natural frequency both for TLCGD installed but without water and tuned TLCGD are shown in Figs. 2 and 3.
The response in the form of ratio of absolute value of acceleration at top plate and base plate of the model over the ratio of excitation frequency to its first natural frequency both for TLCGD installed but without water and tuned TLCGD are shown in Figs. 2 and 3.
Fig. 1: Experimental configuration of laboratory model; green colour of water is due to dye for better visibility of its surface strokes.
Fig. 1: Experimental configuration of laboratory model; green colour of water is due to dye for better visibility of its surface strokes.
Tab. 1: Average + SD of normalized deviation of individuals’ spatial-temporal parameters In conclusion, the simplified gait analysis method can be used for describing he spatial and temporal parameters of a number of gait cycles. T parameters of each subject investigated can calculated. parameters ena The bles the mode normalized ing of dynamic perception, because it is independent from t value of parameters due to normalization. O tests show thai the size of he parameter independent from lateral dominance at healt subjects. The size of the normalized deviation of parameters d he average and standard deviation of Hy epends on age, on the intensity
Tab. 1: Average + SD of normalized deviation of individuals’ spatial-temporal parameters In conclusion, the simplified gait analysis method can be used for describing he spatial and temporal parameters of a number of gait cycles. T parameters of each subject investigated can calculated. parameters ena The bles the mode normalized ing of dynamic perception, because it is independent from t value of parameters due to normalization. O tests show thai the size of he parameter independent from lateral dominance at healt subjects. The size of the normalized deviation of parameters d he average and standard deviation of Hy epends on age, on the intensity
Fig. 1. MTS Synergie 100 loading system and videoextensometer system.
Fig. 1. MTS Synergie 100 loading system and videoextensometer system.
Tab. 2. Values of the stretch ration A2 and (3 for abdominal aortic aneurysms and normal abdominal aorta.
Tab. 2. Values of the stretch ration A2 and (3 for abdominal aortic aneurysms and normal abdominal aorta.
Fig. 2. Stress-strain relationship for abdominal aortic aneurysm cut in circumferential direction (AAAc). Obtained results indicate that incompressibility and isotropy is a reasonable assumption in that AAA tissues under uniaxial tensile tests and can be straightforward applicable to compute the constitutive modeling. They were described fairly precisely by an essential equation derived from used model ( ). The model applied is a phenomenological mode and may be called quasi-structural because of its conformity to the Holzapfel’s and Weizsacker’s postulate [8], which talks about the additive spli of the isochoric strain-energy function into parts connected with the different deformation of a structure; it’s mean connected with elastin and collagen fibres (Fig. 3). It’s very importan mathematical describe behavior of AAAs’ walls under deformation to take into consideration influence of complex structure.
Fig. 2. Stress-strain relationship for abdominal aortic aneurysm cut in circumferential direction (AAAc). Obtained results indicate that incompressibility and isotropy is a reasonable assumption in that AAA tissues under uniaxial tensile tests and can be straightforward applicable to compute the constitutive modeling. They were described fairly precisely by an essential equation derived from used model ( ). The model applied is a phenomenological mode and may be called quasi-structural because of its conformity to the Holzapfel’s and Weizsacker’s postulate [8], which talks about the additive spli of the isochoric strain-energy function into parts connected with the different deformation of a structure; it’s mean connected with elastin and collagen fibres (Fig. 3). It’s very importan mathematical describe behavior of AAAs’ walls under deformation to take into consideration influence of complex structure.
Fig. 3. Collagen and elastin fibres in aortic abdominal aortic aneurysm walls. 3. References [1] G. Holzapfel, R. Ogden, Biomechanics of soft tissue in cardiovascular systems. SpringerWien NewYork (2003).
Fig. 3. Collagen and elastin fibres in aortic abdominal aortic aneurysm walls. 3. References [1] G. Holzapfel, R. Ogden, Biomechanics of soft tissue in cardiovascular systems. SpringerWien NewYork (2003).
Fig. 2: Results of microhardness and RS for the tempered steel W 300 machined by graphite electrode in finishing mode. The state of residual stresses (RS) was determined by X-ray diffraction (XRD), Barkhausen noise (BN) and layer removal methods (LRM). Phase composition of cut area was evaluated by Rietveld line profile analysis from XRD data [3]. Microstructure and chemical composition of white layer and heat affected zone was investigated using optical microscope and electron microprobe with EDX analysis. The samples were also examined for microhardness HV 0.2.
Fig. 2: Results of microhardness and RS for the tempered steel W 300 machined by graphite electrode in finishing mode. The state of residual stresses (RS) was determined by X-ray diffraction (XRD), Barkhausen noise (BN) and layer removal methods (LRM). Phase composition of cut area was evaluated by Rietveld line profile analysis from XRD data [3]. Microstructure and chemical composition of white layer and heat affected zone was investigated using optical microscope and electron microprobe with EDX analysis. The samples were also examined for microhardness HV 0.2.
4. Discussion
4. Discussion
Fig. 1: Loading programme: (a) strain control signals; (b) stress responses. biaxial stress conditions to be achieved in the material tested.
Fig. 1: Loading programme: (a) strain control signals; (b) stress responses. biaxial stress conditions to be achieved in the material tested.
yield point, Fig. 2. The effects are very strong and depend on the amplitude of the torsion cycles. An increase of the cyclic shear strain amplitude leads to the further decrease of the stress-strain characteristic and the ductility improvement. 4. Remarks Fig. 3: Comparison of the initial yield surface (0) and subsequent yield loci determined after mono- tonic tension and torsion cycles for the strain ampli- tudes equal to 0.3% (1). £0.5% (2). 0.7% (3).
yield point, Fig. 2. The effects are very strong and depend on the amplitude of the torsion cycles. An increase of the cyclic shear strain amplitude leads to the further decrease of the stress-strain characteristic and the ductility improvement. 4. Remarks Fig. 3: Comparison of the initial yield surface (0) and subsequent yield loci determined after mono- tonic tension and torsion cycles for the strain ampli- tudes equal to 0.3% (1). £0.5% (2). 0.7% (3).
The photographs of isochromatic pattern were taken for the models (fig.1) under various levels of loading in elastic-plastic range. The isochromatic fringes taken for the model III (with three holes) for a dark-field polariscope at chosen loading levels are shown on fig.2. Fig.2. Isochromatic fringes at loading levels: a) s = 0.879, b) s = 0.928 levels of loading in elastic-plastic range. The ihe strain components separation on the basis of the isochromatic fringes was held using the analytical method of characteristic. This method makes use of the relations between the
The photographs of isochromatic pattern were taken for the models (fig.1) under various levels of loading in elastic-plastic range. The isochromatic fringes taken for the model III (with three holes) for a dark-field polariscope at chosen loading levels are shown on fig.2. Fig.2. Isochromatic fringes at loading levels: a) s = 0.879, b) s = 0.928 levels of loading in elastic-plastic range. The ihe strain components separation on the basis of the isochromatic fringes was held using the analytical method of characteristic. This method makes use of the relations between the
Fig.1. Models of the constructional elements. Corresponding author: B.Kozlowska@mchtr.pw.edu.pl Warsaw University of Technology, Faculty of Mechatronical Engineering, ul. Sw. Andrzeja Boboli 8, 02-525 Warsaw, Poland.
Fig.1. Models of the constructional elements. Corresponding author: B.Kozlowska@mchtr.pw.edu.pl Warsaw University of Technology, Faculty of Mechatronical Engineering, ul. Sw. Andrzeja Boboli 8, 02-525 Warsaw, Poland.
Fig. 3. Model of the material characteristic For strain separation and determination of the stress components in the elastic-plastic zones of the models, the 6-sectional model of material characteristic was accepted (fig.3). 3. Conclusions
Fig. 3. Model of the material characteristic For strain separation and determination of the stress components in the elastic-plastic zones of the models, the 6-sectional model of material characteristic was accepted (fig.3). 3. Conclusions
Fig. 4. Analyzed area of model with three holes for loading level s = 0.928
Fig. 4. Analyzed area of model with three holes for loading level s = 0.928
Fig. 5. Stress distribution 0, (x, y) for s = 0.928
Fig. 5. Stress distribution 0, (x, y) for s = 0.928
Fig.6. Stress distribution o, (x, y) for s = 0.928
Fig.6. Stress distribution o, (x, y) for s = 0.928
scan length). This results in the material fraction in a certain profile height. The Abbott curve is then created by plotting the height steps over the corresponding material fraction (see Fig. 2 and Fig. 5). The approach to determine the tribologically relevant Abbott parameters is shown in Fig. 2.
scan length). This results in the material fraction in a certain profile height. The Abbott curve is then created by plotting the height steps over the corresponding material fraction (see Fig. 2 and Fig. 5). The approach to determine the tribologically relevant Abbott parameters is shown in Fig. 2.
Fig. 2: Evaluation of the secant with minimal inclination
Fig. 2: Evaluation of the secant with minimal inclination
3. Conclusion The Abbott parameters for surface profiles investigated with stylus instruments and with confocal laser scanning microscopes show a significant difference. To find out the reason for this phenomenon, a method for simulating the movement of the stylus edge over the surface profile was developed (see fig. 5). Through the motion of the stylus over the profile, the edge produces an envelope which was taken to be responsible for the difference between the Abbott parameters. The stylus edge was formed with a radius of 5 um and an opening angle of 90°.
3. Conclusion The Abbott parameters for surface profiles investigated with stylus instruments and with confocal laser scanning microscopes show a significant difference. To find out the reason for this phenomenon, a method for simulating the movement of the stylus edge over the surface profile was developed (see fig. 5). Through the motion of the stylus over the profile, the edge produces an envelope which was taken to be responsible for the difference between the Abbott parameters. The stylus edge was formed with a radius of 5 um and an opening angle of 90°.
Fig. 6: Stylus edge touching the surface profile From the new surface profile which is given by the envelope the Abbott parameters were calculated again.
Fig. 6: Stylus edge touching the surface profile From the new surface profile which is given by the envelope the Abbott parameters were calculated again.
Fig. 1: Requirements on reinforcing tire cords. Therefore tire steel-cords are exposed to various chemical and thermal influences (fig. 1) during cyclic loading states by _ tensile- compression in tire loading processes. The aggressive environment (e.g. action of salts in winter) activates the corroding process ym steel-cord surfaces [2]. If cords are with
Fig. 1: Requirements on reinforcing tire cords. Therefore tire steel-cords are exposed to various chemical and thermal influences (fig. 1) during cyclic loading states by _ tensile- compression in tire loading processes. The aggressive environment (e.g. action of salts in winter) activates the corroding process ym steel-cord surfaces [2]. If cords are with
The experimental study of macro and microstructures of tire e.g. belt plies is also important for computational modelling of tire. Fig. 3: Tensile test of steel belt ply with corrosion.
The experimental study of macro and microstructures of tire e.g. belt plies is also important for computational modelling of tire. Fig. 3: Tensile test of steel belt ply with corrosion.
Fig. 2: Damage adhesive bond “steel-cord surfaces- elastomer drift”. 2. Experimental Results
Fig. 2: Damage adhesive bond “steel-cord surfaces- elastomer drift”. 2. Experimental Results
Fig. 5: Comparison of corrosion degradation and undamaged of steel belt ply.
Fig. 5: Comparison of corrosion degradation and undamaged of steel belt ply.
It is necessary also knowledge about tensile stiffness of belt ply with corrosion for different cord angles and cord form, fig. 3. The fracture character of test specimen with 25° angle and thin wire cord after tensile and corrosion test in a corrosion chamber is on fig. 4 as an example. Fig. 4: Sample of fracture character of test specimen with corrosion and detail corrosion on cord surfaces.
It is necessary also knowledge about tensile stiffness of belt ply with corrosion for different cord angles and cord form, fig. 3. The fracture character of test specimen with 25° angle and thin wire cord after tensile and corrosion test in a corrosion chamber is on fig. 4 as an example. Fig. 4: Sample of fracture character of test specimen with corrosion and detail corrosion on cord surfaces.
rT his paper deals with parallel overview o numerical calculations and static testing results fo a typical truss as a primary structural element of the steel roof construction in new Varazdin Spor Hall. This Sport Hall is one among other few sport auditoriums that had been designed and buil during 2008. for the purpose of World handbal championship held in Croatia in January 2009. Sport building codes and regulations were not the only and crucial requirements for construction type selection and design for this 5000 audience, but also awarded architectural solution, construction technology, and the most important short time for building erection. Therefore, for this 63 x 84 m plan, simple triangular braced girder was selected as the primary structural element for steel roof construction (Figure 1). So, all long term roof counterfort works, needed surely for more attractive space structures, were avoided. i ’
rT his paper deals with parallel overview o numerical calculations and static testing results fo a typical truss as a primary structural element of the steel roof construction in new Varazdin Spor Hall. This Sport Hall is one among other few sport auditoriums that had been designed and buil during 2008. for the purpose of World handbal championship held in Croatia in January 2009. Sport building codes and regulations were not the only and crucial requirements for construction type selection and design for this 5000 audience, but also awarded architectural solution, construction technology, and the most important short time for building erection. Therefore, for this 63 x 84 m plan, simple triangular braced girder was selected as the primary structural element for steel roof construction (Figure 1). So, all long term roof counterfort works, needed surely for more attractive space structures, were avoided. i ’
Numerical analysis of such subsequently softened girders had to be checked by static load testing. Corresponding autor: ivan.paska@coning.hr
Numerical analysis of such subsequently softened girders had to be checked by static load testing. Corresponding autor: ivan.paska@coning.hr
Figure 6: Deflections during the test procedure The results of measured deflections on measuring places No. 6, 7 and 8 can be seen in Figure 5 and compared with computational values in Figure 6 and Table 1. The results of measured strains on measuring places No.1 and 2 are shown in Figure
Figure 6: Deflections during the test procedure The results of measured deflections on measuring places No. 6, 7 and 8 can be seen in Figure 5 and compared with computational values in Figure 6 and Table 1. The results of measured strains on measuring places No.1 and 2 are shown in Figure
“eae 3. Experimental results and comparison with numerical results of testing 4. Conclusions
“eae 3. Experimental results and comparison with numerical results of testing 4. Conclusions
Figure 7: Comparison of experimental and numerical deflections Table 1: Comparison of experimental and numerical deflections
Figure 7: Comparison of experimental and numerical deflections Table 1: Comparison of experimental and numerical deflections
From the measured strains stresses are calculated and compared with computational values in Table
From the measured strains stresses are calculated and compared with computational values in Table
Due to the time and budged restriction it was not possible to build testing loading equipment capable to perform a radial loading evaluation. The decision was to rely on numerical model of radially loaded spider fitting and spherical joint attachment. It is not the problem to build such a numerical model based on CAD geometry, but problem is to rely on such a model. Numerical methods, such as FEM, are always giving logical results, but question is how accurate is the numerical model.
Due to the time and budged restriction it was not possible to build testing loading equipment capable to perform a radial loading evaluation. The decision was to rely on numerical model of radially loaded spider fitting and spherical joint attachment. It is not the problem to build such a numerical model based on CAD geometry, but problem is to rely on such a model. Numerical methods, such as FEM, are always giving logical results, but question is how accurate is the numerical model.
have been used to detect the deformations of laded pair of spiders (Fig.1). When comparing the results, it is important to apply the unidirectiona strain gage in the region where principal strain direction can easily be selected. As a strain gage averages deformations on whole region of application, the region of application has to be free from stress concentrations. Therefore a numerica model, based on the CAD geometry, is the firs step needed to locate such a region. For the case of spherical joint attachment, the frictional contact problem has to be considered. Thus a numerical model of spherical joint attachment is modeled and compared with experimental data for axial loading test. The load- displacement data, deformed shape and rupture scenario have been compared. From the numerical model it can be concluded that collapse occurs due to the plastic deformation of cylindrical body and plastic yielding due to the Hertzian stresses few microns under the sphere’s surface (Fig. 3 and 4).
have been used to detect the deformations of laded pair of spiders (Fig.1). When comparing the results, it is important to apply the unidirectiona strain gage in the region where principal strain direction can easily be selected. As a strain gage averages deformations on whole region of application, the region of application has to be free from stress concentrations. Therefore a numerica model, based on the CAD geometry, is the firs step needed to locate such a region. For the case of spherical joint attachment, the frictional contact problem has to be considered. Thus a numerical model of spherical joint attachment is modeled and compared with experimental data for axial loading test. The load- displacement data, deformed shape and rupture scenario have been compared. From the numerical model it can be concluded that collapse occurs due to the plastic deformation of cylindrical body and plastic yielding due to the Hertzian stresses few microns under the sphere’s surface (Fig. 3 and 4).
Table 1 Loading capacity, evaluated and declared 5. Concluding remarks
Table 1 Loading capacity, evaluated and declared 5. Concluding remarks
Figure 3 FEM model of the spherical joint wiht stress concetration due to the Hertzian stresses Figure 4 Yealding of the sphereical joint due to the Hertzian stresses and deformation of cylindrical body
Figure 3 FEM model of the spherical joint wiht stress concetration due to the Hertzian stresses Figure 4 Yealding of the sphereical joint due to the Hertzian stresses and deformation of cylindrical body
Figure 5 The simulation of radial loading
Figure 5 The simulation of radial loading
In this concern it must be kept in mind, that in modern measurement techniques (e.g. electrical, optical, fibre-optical- methods) the respective signals like changes in resistance, voltage, intensities and frequencies etc. are measured. These analogue signals are to transform according to the inherent features of the respective technique and the relation between the metered signals and_ the displacements and strain (fig. 1). Fig. 1: Relation metered signals to strain and displacements.
In this concern it must be kept in mind, that in modern measurement techniques (e.g. electrical, optical, fibre-optical- methods) the respective signals like changes in resistance, voltage, intensities and frequencies etc. are measured. These analogue signals are to transform according to the inherent features of the respective technique and the relation between the metered signals and_ the displacements and strain (fig. 1). Fig. 1: Relation metered signals to strain and displacements.
The quantities C, v, 0, are unknown, thus a mixed inverse problem is on hand. A separation of the unknown quantities becomes necessary and will be carried out by means of the sensitivity matrix based method (eq.(4)).
The quantities C, v, 0, are unknown, thus a mixed inverse problem is on hand. A separation of the unknown quantities becomes necessary and will be carried out by means of the sensitivity matrix based method (eq.(4)).
In component formulation eq. (3) holds The strains ¢; have been obtained by evaluation of metered signals.
In component formulation eq. (3) holds The strains ¢; have been obtained by evaluation of metered signals.
The main elements of the upper structure of the classical rail track constructions are the rails, sleepers and the track screen (the ballast). The connection of the rails and the sleepers is achieved by an appropriate method of fastening. The Fig. 1 shows the longitudinal cross-section of the classical rail track construction, [1]. If the rail track ballast is observed, its main purpose is to elastically and equally transfer the loads caused by the rail vehicles to the plane of the lower structure, to secure the direction and height of the rail track and to dampen the vibrations in the rail track. For the ballast to fulfil the said requirements, it must have sufficient dimensions (width and thickness) and must be constructed of a good quality material. The best material for the ballast is crushed stone produced by eruptive origin. The optimal thickness of the ballast is 25 to 30 cm measured from the lower par of the sleeper (Fig. 1). This paper considers impact of the thickness of the ballast on the vertical stability of the rail rack. The measurements were performed on he rail grid of the Croatian Railways (location: Skrljevo - Meja - Pecine). The said section is in a cut and has longitudinal slope of 22 %o, hickness of the ballast amounts to 15 to 20 cm. During the year 2005 the wooden sleepers were replaced with the concrete sleepers. But, after wo years from the replacement, the new
The main elements of the upper structure of the classical rail track constructions are the rails, sleepers and the track screen (the ballast). The connection of the rails and the sleepers is achieved by an appropriate method of fastening. The Fig. 1 shows the longitudinal cross-section of the classical rail track construction, [1]. If the rail track ballast is observed, its main purpose is to elastically and equally transfer the loads caused by the rail vehicles to the plane of the lower structure, to secure the direction and height of the rail track and to dampen the vibrations in the rail track. For the ballast to fulfil the said requirements, it must have sufficient dimensions (width and thickness) and must be constructed of a good quality material. The best material for the ballast is crushed stone produced by eruptive origin. The optimal thickness of the ballast is 25 to 30 cm measured from the lower par of the sleeper (Fig. 1). This paper considers impact of the thickness of the ballast on the vertical stability of the rail rack. The measurements were performed on he rail grid of the Croatian Railways (location: Skrljevo - Meja - Pecine). The said section is in a cut and has longitudinal slope of 22 %o, hickness of the ballast amounts to 15 to 20 cm. During the year 2005 the wooden sleepers were replaced with the concrete sleepers. But, after wo years from the replacement, the new
sleepers sunk due to further crushing of the ballast (Fig. 2). Due to subsequent crushing, the crushed stones lost their sharp edged form, which in tum lead to reduction of mutual wedging of the granules, which finally lead to settlement of the sleepers. Fig. 2: Settlement of the concrete sleepers.
sleepers sunk due to further crushing of the ballast (Fig. 2). Due to subsequent crushing, the crushed stones lost their sharp edged form, which in tum lead to reduction of mutual wedging of the granules, which finally lead to settlement of the sleepers. Fig. 2: Settlement of the concrete sleepers.
Fig. 4: Deflection of the sleeper (operational train).
Fig. 4: Deflection of the sleeper (operational train).
transversal shifts or vibrations of the constructions simultaneously in two orthogonal directions. The device is based on a laser transmitter and optic-electronic receiver that are mounted on the object where the measurements are being made. The Fig. 3 show the measuring equipment PSM90 fitted on the rail track.
transversal shifts or vibrations of the constructions simultaneously in two orthogonal directions. The device is based on a laser transmitter and optic-electronic receiver that are mounted on the object where the measurements are being made. The Fig. 3 show the measuring equipment PSM90 fitted on the rail track.
Fig. 5: Deflection of the sleeper (freight train).
Fig. 5: Deflection of the sleeper (freight train).
Fig. 6: Deflection of the sleeper (passenger train).
Fig. 6: Deflection of the sleeper (passenger train).
The scheme of the part of stainless steel sealing component for air condition system is shown in fig. 1. Fig. 1: The scheme of the part of measured component (side and top view).
The scheme of the part of stainless steel sealing component for air condition system is shown in fig. 1. Fig. 1: The scheme of the part of measured component (side and top view).
Fig. 2: Image of parts of circular teeth with height measurement. First, height of each tooth was measured according to the reference plane (fig. 2, 3). Average height was computed to be 217 um for the outer circle and 242 um for the inner one with 2 um standard deviation.
Fig. 2: Image of parts of circular teeth with height measurement. First, height of each tooth was measured according to the reference plane (fig. 2, 3). Average height was computed to be 217 um for the outer circle and 242 um for the inner one with 2 um standard deviation.
Fig. 3: X-Z profile 10 from the previous image.
Fig. 3: X-Z profile 10 from the previous image.
Fig. 2: Tension test — fibres angle 30° and 45°. Fig. 1: Bending test — fibres angle 30° and 45°. Fig. 1 shows that both computational models give contradictory results. Results obtained by the bimaterial model show always a higher stiffness than results obtained by the unimaterial model. A causation of the difference between results is obviously due to the zero bending stiffness in the unimaterial model as mentioned in introduction.
Fig. 2: Tension test — fibres angle 30° and 45°. Fig. 1: Bending test — fibres angle 30° and 45°. Fig. 1 shows that both computational models give contradictory results. Results obtained by the bimaterial model show always a higher stiffness than results obtained by the unimaterial model. A causation of the difference between results is obviously due to the zero bending stiffness in the unimaterial model as mentioned in introduction.
test. Complete results for all declinations of fibres were published in [5].
test. Complete results for all declinations of fibres were published in [5].
The cement samples were prepared by hand and vacuum mixing technique, both with exact timing. The quantitative composition of the used bone cement is presented in Tab. 1.
The cement samples were prepared by hand and vacuum mixing technique, both with exact timing. The quantitative composition of the used bone cement is presented in Tab. 1.
Fig. 1: Surface temperature courses of the hand- mixed samples with 2mm thickness The measured surface temperature courses are represented in Fig. | - 4. The averaged values of peak temperatures and times required to obtain the peak temperatures are represented in Tab. 2 - 3.
Fig. 1: Surface temperature courses of the hand- mixed samples with 2mm thickness The measured surface temperature courses are represented in Fig. | - 4. The averaged values of peak temperatures and times required to obtain the peak temperatures are represented in Tab. 2 - 3.
Fig. 2: Surface temperature courses of the hand- mixed samples with 5mm thickness
Fig. 2: Surface temperature courses of the hand- mixed samples with 5mm thickness
Tab. 2: Averaged values of peak temperatures and times required to obtain the peak temperatures of differently thick hand-mixed cement samples Fig. 3: Surface temperature courses of the vacuum- mixed samples with 2mm thickness
Tab. 2: Averaged values of peak temperatures and times required to obtain the peak temperatures of differently thick hand-mixed cement samples Fig. 3: Surface temperature courses of the vacuum- mixed samples with 2mm thickness
‘ig. 4: Surface temperature courses of the vacuum- mixed samples with 5mm thickness
‘ig. 4: Surface temperature courses of the vacuum- mixed samples with 5mm thickness
Fig. 2: Results of wear measurements. The coefficient of traction was monitored during each test and mainly disc weight loss, disc diameter loss, hardness and_ surface roughness were investigated at the end of every test. After specimen sectioning the surface layer was prepared for metallographic observation in order to gain a conception about maximal defects and shear strain accumulation. Some results of the contact fatigue with fixed slipping can be seen in Fig. 2. At the same time, measurements of residual stresses are provided before and after contact loading. Three methods of experimental stress analysis were used for measurements — hole drilling strain gage method, X-ray diffraction method and magnetoelastic method. The residual stresses before contact loading are relatively small and tensile (~5O0 MPa). The
Fig. 2: Results of wear measurements. The coefficient of traction was monitored during each test and mainly disc weight loss, disc diameter loss, hardness and_ surface roughness were investigated at the end of every test. After specimen sectioning the surface layer was prepared for metallographic observation in order to gain a conception about maximal defects and shear strain accumulation. Some results of the contact fatigue with fixed slipping can be seen in Fig. 2. At the same time, measurements of residual stresses are provided before and after contact loading. Three methods of experimental stress analysis were used for measurements — hole drilling strain gage method, X-ray diffraction method and magnetoelastic method. The residual stresses before contact loading are relatively small and tensile (~5O0 MPa). The
Fig. 3: Courses of principal stresses in pulley after 2 000 000 cycles by hole drilling method.
Fig. 3: Courses of principal stresses in pulley after 2 000 000 cycles by hole drilling method.
Fig. 4: Residual stresses by X-ray diffraction measurement.
Fig. 4: Residual stresses by X-ray diffraction measurement.
The results of residual stresses obtained by means of X-ray diffraction method after 2 000 000 cycles is shown in Fig. 4.
The results of residual stresses obtained by means of X-ray diffraction method after 2 000 000 cycles is shown in Fig. 4.
Fig. 1: Positions of Strain Gages and Transducers on Testing Specimen To determine buckling load of axially compressed composite panel here strain gauges are used. Strain gauges were applied on both sides of the layered composite plate in loading direction, Fig. 1.
Fig. 1: Positions of Strain Gages and Transducers on Testing Specimen To determine buckling load of axially compressed composite panel here strain gauges are used. Strain gauges were applied on both sides of the layered composite plate in loading direction, Fig. 1.
Finite element model and first buckling mode is shown in Fig. 3. In Figure 4 are given experimental and computation results of buckling and post-buckling behaviour using relation between load P and out of plane displacements (W).
Finite element model and first buckling mode is shown in Fig. 3. In Figure 4 are given experimental and computation results of buckling and post-buckling behaviour using relation between load P and out of plane displacements (W).
Fig. 3 The First Buckling Mode by FEM Much research has been conducted on buc kling composite plates. A review of the subject by Leissa' quotes more than 90 references. Most of his work is theoretical in nature, and very if any, attention is given to post-buc post-buckling behaviour”*. ittle, kling behaviour. To determine stability behaviour of composite panel here non-linear finite element analysis is used to determine buckling load and
Fig. 3 The First Buckling Mode by FEM Much research has been conducted on buc kling composite plates. A review of the subject by Leissa' quotes more than 90 references. Most of his work is theoretical in nature, and very if any, attention is given to post-buc post-buckling behaviour”*. ittle, kling behaviour. To determine stability behaviour of composite panel here non-linear finite element analysis is used to determine buckling load and
Fig. 1: Phoenix electrical locomotive After such modification, tests are made in purpose to obtain a new certification from a Railway Commission. The tests were carried out according to ERRI B12/RP 17 (ERRI — European Railway Research Institute). 2. Measurement points
Fig. 1: Phoenix electrical locomotive After such modification, tests are made in purpose to obtain a new certification from a Railway Commission. The tests were carried out according to ERRI B12/RP 17 (ERRI — European Railway Research Institute). 2. Measurement points
3. Tests The acquisition software used was Catman 4.5 (an Hottinger product). The tests were performed in two steps:
3. Tests The acquisition software used was Catman 4.5 (an Hottinger product). The tests were performed in two steps:
5. Conclusions In the figure 3 is presented graphically how the tests were done.
5. Conclusions In the figure 3 is presented graphically how the tests were done.
Regarding to Goodman — Smith diagram, al measured stresses were on “a2” curve (figure 3). The results, was smaller than permissible stress, so we can concluded that the design solution used by manufacturer was good.
Regarding to Goodman — Smith diagram, al measured stresses were on “a2” curve (figure 3). The results, was smaller than permissible stress, so we can concluded that the design solution used by manufacturer was good.
Fig. 2: Dabar Bridge — structural system. Dabar Bridge, fig. 1, is 330 meters long double bridge (separate longitudinal structures for every traffic direction), over seven spans of 40 + 5 x 50 + 40 meters. It was designed as classical reinforced concrete plane frame system with longitudinal I-girders (fig. 2) connected only with continuous 20 centimetres thick reinforced concrete deck.
Fig. 2: Dabar Bridge — structural system. Dabar Bridge, fig. 1, is 330 meters long double bridge (separate longitudinal structures for every traffic direction), over seven spans of 40 + 5 x 50 + 40 meters. It was designed as classical reinforced concrete plane frame system with longitudinal I-girders (fig. 2) connected only with continuous 20 centimetres thick reinforced concrete deck.
Fig. 3: Dabar Bridge — static loading. Static load was performed with six trucks weighting approximately 35 metric tonnes each, see fig. 3, placed in the mid-spans. Vertical displacements were measured by geodetic method of levelling in every span along four lines (A, B, C and D), over the supports (1, 3, 5, 7, etc.) and in the mid-spans (2, 4, 6, 8, etc.), altogether at 12 points on each span.
Fig. 3: Dabar Bridge — static loading. Static load was performed with six trucks weighting approximately 35 metric tonnes each, see fig. 3, placed in the mid-spans. Vertical displacements were measured by geodetic method of levelling in every span along four lines (A, B, C and D), over the supports (1, 3, 5, 7, etc.) and in the mid-spans (2, 4, 6, 8, etc.), altogether at 12 points on each span.
4. Numerical Analyses
4. Numerical Analyses
5. Comparison of Results
5. Comparison of Results
Fig. 1: Grandstand RC girder cross-section. 2. Single Girder Testing
Fig. 1: Grandstand RC girder cross-section. 2. Single Girder Testing
Strains of concrete were measured by Barry movable extensometer positioned at the supports and in the mid-span, see fig. 3.
Strains of concrete were measured by Barry movable extensometer positioned at the supports and in the mid-span, see fig. 3.
3. Assembled Girder Testing
3. Assembled Girder Testing
Fig. 5: Assembled grandstand structure. Assembled girders were connected in the thirds of the spans creating monolithical grandstand structure, fig 5. Only dynamic testing was performed by jumping of humans.
Fig. 5: Assembled grandstand structure. Assembled girders were connected in the thirds of the spans creating monolithical grandstand structure, fig 5. Only dynamic testing was performed by jumping of humans.
Maximal designed bending moment i.e. corresponding testing load is presented in fig. 6. Fig. 6: Static loading performance.
Maximal designed bending moment i.e. corresponding testing load is presented in fig. 6. Fig. 6: Static loading performance.
5. Numerical Analyses
5. Numerical Analyses
Fig. 1: Manner of collecting sample: cutting slice a), cutting sample b), sample c) Corresponding author: adam.mazurkiewicz@utp.edu.pl
Fig. 1: Manner of collecting sample: cutting slice a), cutting sample b), sample c) Corresponding author: adam.mazurkiewicz@utp.edu.pl
Tab. 2: Value of determination coefficient R’ for the relationship of BMD with fractal dimension
Tab. 2: Value of determination coefficient R’ for the relationship of BMD with fractal dimension
Tab. 1: Value of determination coefficient R° for the relationship of BMD with volume of layer between BMD and fractal dimensions. In the tables, maximal values of R’ are presented for the study of the description of power, logarithmic and numerical functions.
Tab. 1: Value of determination coefficient R° for the relationship of BMD with volume of layer between BMD and fractal dimensions. In the tables, maximal values of R’ are presented for the study of the description of power, logarithmic and numerical functions.
To characterize the deformation behaviour of timing belt tooth during the contact with a steel counterpart a novel testing device was developed and implemented on a servohydraulic testing machine and the set-up is shown Fig 2. The belt was preloaded in the test equipment and the belt tooth was loaded by the movement of a steel counterpart pulley. The local strains in the contact area and in the entire tooth were measured by digital image correlation technique. The development of the major strain during the loading stages is shown in Fig. 3 for a specific belt type and tooth profile. The highly
To characterize the deformation behaviour of timing belt tooth during the contact with a steel counterpart a novel testing device was developed and implemented on a servohydraulic testing machine and the set-up is shown Fig 2. The belt was preloaded in the test equipment and the belt tooth was loaded by the movement of a steel counterpart pulley. The local strains in the contact area and in the entire tooth were measured by digital image correlation technique. The development of the major strain during the loading stages is shown in Fig. 3 for a specific belt type and tooth profile. The highly
Fig. 1: The device designed fort the belt deformation test.
Fig. 1: The device designed fort the belt deformation test.
Fig. 3: Major strain vs. displacement curves along with the corresponding deformation images for a belt. loaded local area (above 30 % local strain) is clearly recognized in the images above the curve.
Fig. 3: Major strain vs. displacement curves along with the corresponding deformation images for a belt. loaded local area (above 30 % local strain) is clearly recognized in the images above the curve.
Fig. 4: The view of the belt test system While above tests were carried out on laboratory tests specimen level a further test system for real component tests was also developed. In opposite to the laboratory tests this system is not manufactured yet but it could be easily realized in a short time. The overall view of the belt test system is shown in Fig. 4.
Fig. 4: The view of the belt test system While above tests were carried out on laboratory tests specimen level a further test system for real component tests was also developed. In opposite to the laboratory tests this system is not manufactured yet but it could be easily realized in a short time. The overall view of the belt test system is shown in Fig. 4.
The loading unit could be combined with a novel non-contact torque measurement system and this integration is shown in Fig. 6. High temperature tests could be performed using the NCTE device.
The loading unit could be combined with a novel non-contact torque measurement system and this integration is shown in Fig. 6. High temperature tests could be performed using the NCTE device.
Fig. 6: The loading unit with the NCTE (Non- Contact- Torque- Engineering) device integrated.
Fig. 6: The loading unit with the NCTE (Non- Contact- Torque- Engineering) device integrated.
Fig. 2: Comparison of average values of dh/dP(t) versus P for rejuvenated material (full marks) and aged material, for three different rates of loading
Fig. 2: Comparison of average values of dh/dP(t) versus P for rejuvenated material (full marks) and aged material, for three different rates of loading
the dh/dP values for various loading rates and materials. What differs is the history of indentation depth A(t) in the individual tests. Fig.3 presents an example of a risk connected with the application of Eq. (4) with a second derivation in the analysis.
the dh/dP values for various loading rates and materials. What differs is the history of indentation depth A(t) in the individual tests. Fig.3 presents an example of a risk connected with the application of Eq. (4) with a second derivation in the analysis.
Fig. 1: Experimental testing of ceramic tiles in three- point bending. The testing procedure uses the digital image correlation method and the ARAMIS system [3] as a main experimental setup. The digital image correlation method offers a precise optical solution for deformation measurements. ARAMIS is a non-contact optical deformation measuring system which analyzes, calculates and documents material deformations, being particularly suitable for three-dimensional deformation measurements under static and dynamic loading in order to analyze deformations and strains of real components. If the measuring object has only a few object characteristics, like it is the case with homogeneous surfaces, one needs to prepare such surfaces by applying a stochastic spray pattern. The experimental set-up is shown in Fig. 1, with the force applied from the top. We have to underline that some geometry imperfections were probably the cause for some
Fig. 1: Experimental testing of ceramic tiles in three- point bending. The testing procedure uses the digital image correlation method and the ARAMIS system [3] as a main experimental setup. The digital image correlation method offers a precise optical solution for deformation measurements. ARAMIS is a non-contact optical deformation measuring system which analyzes, calculates and documents material deformations, being particularly suitable for three-dimensional deformation measurements under static and dynamic loading in order to analyze deformations and strains of real components. If the measuring object has only a few object characteristics, like it is the case with homogeneous surfaces, one needs to prepare such surfaces by applying a stochastic spray pattern. The experimental set-up is shown in Fig. 1, with the force applied from the top. We have to underline that some geometry imperfections were probably the cause for some
Fig. 2: Device used for the experimental testing of ceramic tiles by applying the force through a bullet. A second type of tests consideres the application of the force directly through a steel bullet in the middle of the ceramic tile. A specially designed device allows the transmision of the force from vertical to horizontal direction. The opposite face to the one on which the bullet acts can be viewed directly by the cameras of the ARAMIS system. In this way one can notice better what happens on most of the surface of the tile; the tile is supported on its edges for about 3-4 mm along the perimeter. In Fig.2 can be observed a lateral view of the device fixed in the lower hydraulic grip of the testing machine and a front view of the tile with the two cameras of the ARAMIS system prepared for acquiring data during testing.
Fig. 2: Device used for the experimental testing of ceramic tiles by applying the force through a bullet. A second type of tests consideres the application of the force directly through a steel bullet in the middle of the ceramic tile. A specially designed device allows the transmision of the force from vertical to horizontal direction. The opposite face to the one on which the bullet acts can be viewed directly by the cameras of the ARAMIS system. In this way one can notice better what happens on most of the surface of the tile; the tile is supported on its edges for about 3-4 mm along the perimeter. In Fig.2 can be observed a lateral view of the device fixed in the lower hydraulic grip of the testing machine and a front view of the tile with the two cameras of the ARAMIS system prepared for acquiring data during testing.
he back surface we can analyze _ the displacements fields on the three directions and he major, minor or equivalent (Mises) strain ields. As an example, for the specimen denoted CM 15-1 (zirconia toughened alumina mixed with calcium-magnesium), we show just before ailure at a force of 11470 N the Mises strain ield and the out of plane displacement (Fig. 3); the strain field is localized quite in the middle of the specimen with a maximum value of about 0.22 %, but the displacement field show some noise and that the tile rests in fac more on two diagonal corners due to a non-fla surface — with a maximum value of abou 17-107 mm (for such small values the observed noise is expected). 17-10~° mm (for such small values the observed
he back surface we can analyze _ the displacements fields on the three directions and he major, minor or equivalent (Mises) strain ields. As an example, for the specimen denoted CM 15-1 (zirconia toughened alumina mixed with calcium-magnesium), we show just before ailure at a force of 11470 N the Mises strain ield and the out of plane displacement (Fig. 3); the strain field is localized quite in the middle of the specimen with a maximum value of about 0.22 %, but the displacement field show some noise and that the tile rests in fac more on two diagonal corners due to a non-fla surface — with a maximum value of abou 17-107 mm (for such small values the observed noise is expected). 17-10~° mm (for such small values the observed
Fig. 4 Experimental setup with High Speed cameras, calibration target, loudspeaker and frequency generator for vibration measurements.
Fig. 4 Experimental setup with High Speed cameras, calibration target, loudspeaker and frequency generator for vibration measurements.
Eberhard.Moser@dantecdynamics.com Dantec Dynamics GmbH, Kaessbohrerstr. 18, 89077 Ulm, Germany.
Eberhard.Moser@dantecdynamics.com Dantec Dynamics GmbH, Kaessbohrerstr. 18, 89077 Ulm, Germany.
Fig. 5 Full field out- of plane deformation of the membrane at minimum deflection in the center (top) and temporal plot of the displacement of the center point (bottom).
Fig. 5 Full field out- of plane deformation of the membrane at minimum deflection in the center (top) and temporal plot of the displacement of the center point (bottom).
Fig. 2: Traces of radiograph of L3/L4A segment transformed onto the z-x plane and intersections of
Fig. 2: Traces of radiograph of L3/L4A segment transformed onto the z-x plane and intersections of
spatial motions were measured following force systems consisting of laterally directed torque T,() following triangular time functions (periodic time 21min) and static axial preloads F, with precisely adjusted force lines (+0.5mm) which served as parameter. The spatial resolution of position of the moved co-ordinate system was 0.5um for the translation of its origin and 0.5mdeg for flexion/extension. Thus, IHA-position could a. be determined as function of the flexional angle a in close approximation since small rotational angle intervals (Aa < ROM/400) were used for calculating the IHA-position, b. be related to the varying differential stiffness of the flexional angle-torque characteristics, and c. also to anatomical structures. See also: [1], [2].
spatial motions were measured following force systems consisting of laterally directed torque T,() following triangular time functions (periodic time 21min) and static axial preloads F, with precisely adjusted force lines (+0.5mm) which served as parameter. The spatial resolution of position of the moved co-ordinate system was 0.5um for the translation of its origin and 0.5mdeg for flexion/extension. Thus, IHA-position could a. be determined as function of the flexional angle a in close approximation since small rotational angle intervals (Aa < ROM/400) were used for calculating the IHA-position, b. be related to the varying differential stiffness of the flexional angle-torque characteristics, and c. also to anatomical structures. See also: [1], [2].
THA in flexion/extension. Parameter: Angle of flexion. e@e@/o0o0: Wide IHA-centrodes over more than 30 mm in flexing/extending motion. THA in flexion/extension. Parameter: Angle of flexion. e@@/c00: Wide IHA-centrodes over more than 30 mm in flexing/extending motion.
THA in flexion/extension. Parameter: Angle of flexion. e@e@/o0o0: Wide IHA-centrodes over more than 30 mm in flexing/extending motion. THA in flexion/extension. Parameter: Angle of flexion. e@@/c00: Wide IHA-centrodes over more than 30 mm in flexing/extending motion.
Fig. 5: Segments L3/L4: Steiner analysis of the characteristics. The relation between actual stiffness The characteristics of all five lumbar segments showed distinct non-linearity. In extension the segments the differential stiffness dTy/da = D(a) increased rapidly. Accordingly, the IHA migrated to the dorsal. We related segment stiffness D(a) to IHA position via the Theorem of Steiner (figs. 5,6).
Fig. 5: Segments L3/L4: Steiner analysis of the characteristics. The relation between actual stiffness The characteristics of all five lumbar segments showed distinct non-linearity. In extension the segments the differential stiffness dTy/da = D(a) increased rapidly. Accordingly, the IHA migrated to the dorsal. We related segment stiffness D(a) to IHA position via the Theorem of Steiner (figs. 5,6).
Fig. 3: Bending at the approach angle of 20°, test and numerical simulation
Fig. 3: Bending at the approach angle of 20°, test and numerical simulation
Fig. 2: Bending at the approach angle of 90°, experimental stand and numerical methods Fig. 1: W beam with riveted energy absorbing panel, filled in with foamed aluminum
Fig. 2: Bending at the approach angle of 90°, experimental stand and numerical methods Fig. 1: W beam with riveted energy absorbing panel, filled in with foamed aluminum
Fig. 5. Comparison between experimental results and results of numerical simulation
Fig. 5. Comparison between experimental results and results of numerical simulation
The d curves for the both variants of bending is result of t at the ap fig. 4 the proach angle of 90° is presented. function of W-beam bending with protective panel (two upper functions) compared FEM ca Iculations for W-beam with he experiment. In figs 4 and 5 bending with the function of bending without panel (the down function). In fig. 5 comparison between experimental results and etermination of Displacement-Load ne In he 1S ne ne protective panel with foamed aluminum plate is presented. Fig. 4: Diagram of Displacement-Load received in two subsequent tests for W-beam with and without the panel
The d curves for the both variants of bending is result of t at the ap fig. 4 the proach angle of 90° is presented. function of W-beam bending with protective panel (two upper functions) compared FEM ca Iculations for W-beam with he experiment. In figs 4 and 5 bending with the function of bending without panel (the down function). In fig. 5 comparison between experimental results and etermination of Displacement-Load ne In he 1S ne ne protective panel with foamed aluminum plate is presented. Fig. 4: Diagram of Displacement-Load received in two subsequent tests for W-beam with and without the panel
Fig. 6: Function of Displacement-Load Load received in two subsequent tests for W-beam with and without the panel In figs 6 and 7 the analogical functions for bending at the approach angle of 20°are shown.
Fig. 6: Function of Displacement-Load Load received in two subsequent tests for W-beam with and without the panel In figs 6 and 7 the analogical functions for bending at the approach angle of 20°are shown.
Fig. 7: Comparison between experimental results and results of numerical simulation
Fig. 7: Comparison between experimental results and results of numerical simulation
taken into account: 1.0; 1.5; 2.0; 2.5; 3.0, and 4.0 mm, described in the work [3]. Two materials were used to fill in the tubes: foamed polyvinyl chloride (PCW) (PCHW-1-115) and foamed aluminium (ALPORAS) containing: ~97T% Al, ~1,5% Ca, ~1,5% Ti.
taken into account: 1.0; 1.5; 2.0; 2.5; 3.0, and 4.0 mm, described in the work [3]. Two materials were used to fill in the tubes: foamed polyvinyl chloride (PCW) (PCHW-1-115) and foamed aluminium (ALPORAS) containing: ~97T% Al, ~1,5% Ca, ~1,5% Ti.
Table 1 Mean 3D-structural properties for OA, F and OP groups, obtained from WCT .
Table 1 Mean 3D-structural properties for OA, F and OP groups, obtained from WCT .
Table 3 Coefficient of linear regression R between structural indices and Young’s modulus E, . Osteoarthritis has several phases: formation of osteophytes or joint space narrowing, appearance of subchondral cysts and bone deterioration in this region (which indicates the erosive phase of disease progression) and bone repair and remodelling. The results of our investigations show, that OA samples with osteoarthritis are characterised by higher BV/TV (5,5%), which caused by more complex and thickened structure (Tb.N, Tb.Th, ConnD). This bone concentration (especially in subchondral region) is relevant to gradual loss of cartilage and change in load _ bearing
Table 3 Coefficient of linear regression R between structural indices and Young’s modulus E, . Osteoarthritis has several phases: formation of osteophytes or joint space narrowing, appearance of subchondral cysts and bone deterioration in this region (which indicates the erosive phase of disease progression) and bone repair and remodelling. The results of our investigations show, that OA samples with osteoarthritis are characterised by higher BV/TV (5,5%), which caused by more complex and thickened structure (Tb.N, Tb.Th, ConnD). This bone concentration (especially in subchondral region) is relevant to gradual loss of cartilage and change in load _ bearing
DM degree of mechanical anisotropy Emax/Emin Table 2 Mean mechanical properties E), E>, E3 for OA, F and OP groups, obtained in compression test .
DM degree of mechanical anisotropy Emax/Emin Table 2 Mean mechanical properties E), E>, E3 for OA, F and OP groups, obtained in compression test .
Artificial ageing following — solution treatment is a universally accepted method to strengthen this series of alloys. According to the quasi-binary Al—Mg>Si phase diagram, specimens were solutioned at 530°C with 2 hours holding time and aged at 160°C with 16 hours holding time, for T6 (artificial aging after solution treatment) temper. The parameters of ageing were chosen according to previous experiments, see Fig. 1. Mechanical properties of the peak-aged alloy at room temperature were assessed from the strain-stress curves. The alloy has ultimate tensile strength R, of 307 MPa with an elongation of 10%. The conditions of the impact tests are given by the STN EN 10045-1 standard. The amount of absorbed energy at the breaking of the test bar and the character of the fracture surface are evaluated. The impact tests were performed at the temperatures of 20°C, 00°C, 200°C and 300°C. Two test bars were broken at each temperature. It has been found only negligible influence of the temperature on he amount of absorbed energy during the impact test. The difference in absorbed energy was AKV ~ 9 Joule. On the other hand the significant dependence between temperature and fracture morphology has been found. After impact tests investigated alloy showed
Artificial ageing following — solution treatment is a universally accepted method to strengthen this series of alloys. According to the quasi-binary Al—Mg>Si phase diagram, specimens were solutioned at 530°C with 2 hours holding time and aged at 160°C with 16 hours holding time, for T6 (artificial aging after solution treatment) temper. The parameters of ageing were chosen according to previous experiments, see Fig. 1. Mechanical properties of the peak-aged alloy at room temperature were assessed from the strain-stress curves. The alloy has ultimate tensile strength R, of 307 MPa with an elongation of 10%. The conditions of the impact tests are given by the STN EN 10045-1 standard. The amount of absorbed energy at the breaking of the test bar and the character of the fracture surface are evaluated. The impact tests were performed at the temperatures of 20°C, 00°C, 200°C and 300°C. Two test bars were broken at each temperature. It has been found only negligible influence of the temperature on he amount of absorbed energy during the impact test. The difference in absorbed energy was AKV ~ 9 Joule. On the other hand the significant dependence between temperature and fracture morphology has been found. After impact tests investigated alloy showed
tran: scrystalline ductile failure with dimple morphology. Two categories of dimples on the frac tem ture surfaces of the specimens broken at the perature of 20°C were observed. There were present large dimples formed by coarse intermetallic particles (Fig. 2a) and small dim The dim ples formed by submicroscopic particles. increasing size and decreasing amount of ples with increasing temperature was recorded. For specimen broken at _ the tem perature of 300°C the large dimples with patterning on the surface are characteristic, see Fig. 2b. The results have been explained in terms of slip distribution. Fatigue inves igations were carried out under fully reversed axial loading in the region from N = 10° to frequency resonani ests were conduc N = 10” cycles using high- ultrasonic machine. Fatigue ed under constant amplitude oading at a load ratio R = -1, frequency f ~ 20 kHz and ambient of cycles to failure emperature, using unnotched specimens. The results of fatigue tests were plotted as relation of stress amplitude vs. number in Fig. 3.
tran: scrystalline ductile failure with dimple morphology. Two categories of dimples on the frac tem ture surfaces of the specimens broken at the perature of 20°C were observed. There were present large dimples formed by coarse intermetallic particles (Fig. 2a) and small dim The dim ples formed by submicroscopic particles. increasing size and decreasing amount of ples with increasing temperature was recorded. For specimen broken at _ the tem perature of 300°C the large dimples with patterning on the surface are characteristic, see Fig. 2b. The results have been explained in terms of slip distribution. Fatigue inves igations were carried out under fully reversed axial loading in the region from N = 10° to frequency resonani ests were conduc N = 10” cycles using high- ultrasonic machine. Fatigue ed under constant amplitude oading at a load ratio R = -1, frequency f ~ 20 kHz and ambient of cycles to failure emperature, using unnotched specimens. The results of fatigue tests were plotted as relation of stress amplitude vs. number in Fig. 3.
Fatigue fractures are different from the tensile and impact fractures. Fatigue cracks initiated naturally at the microstructurally weakest points. Non-crystallographic oriented initiation of fatigue crack was observed on all of the fatigue failured specimens (Fig. 4a). At the detailed projection of initiation places of fatigue cracks is documented that after its initiation the crack was non-crystallographic kHz and ambient temperature, using unnotched
Fatigue fractures are different from the tensile and impact fractures. Fatigue cracks initiated naturally at the microstructurally weakest points. Non-crystallographic oriented initiation of fatigue crack was observed on all of the fatigue failured specimens (Fig. 4a). At the detailed projection of initiation places of fatigue cracks is documented that after its initiation the crack was non-crystallographic kHz and ambient temperature, using unnotched
Cc propagated transversally to the direction of external loading approximately 0.2-0.4 mm deep and after reaching this dimension i changed the direction as well as the way of propagation suddenly. The macroscopic propagation direction of magistral crack and the direction of active loading formed an angle of 30-35° whereby the crack was propagated in a crystallographic way on the first stage mode and the fracture surface is therefore faceted. The fracture behaviour affects fatigue properties of the alloys. Fatigue fracture mode is controlled by deformation behaviour and the deformation behaviour is controlled by the interaction of dislocations and second phase particles. Due to he heterogeneous deformation with planar slip bands the fatigue cracks in the peak aged alloy propagated predominantly on the first stage mode and the fractures were faceted (Fig. 4b). Indicia of striations were observed also. 3. Acknowledgements This work has been supported by grant No. 1/0249/09 and projects SK-CZ-0085-07 and SK-CZ-0121-07.
Cc propagated transversally to the direction of external loading approximately 0.2-0.4 mm deep and after reaching this dimension i changed the direction as well as the way of propagation suddenly. The macroscopic propagation direction of magistral crack and the direction of active loading formed an angle of 30-35° whereby the crack was propagated in a crystallographic way on the first stage mode and the fracture surface is therefore faceted. The fracture behaviour affects fatigue properties of the alloys. Fatigue fracture mode is controlled by deformation behaviour and the deformation behaviour is controlled by the interaction of dislocations and second phase particles. Due to he heterogeneous deformation with planar slip bands the fatigue cracks in the peak aged alloy propagated predominantly on the first stage mode and the fractures were faceted (Fig. 4b). Indicia of striations were observed also. 3. Acknowledgements This work has been supported by grant No. 1/0249/09 and projects SK-CZ-0085-07 and SK-CZ-0121-07.
Fig. 1: Relation between operating stress spectrum and failure probability distribution Stage 2, contains extensive laboratory testing of failure probability of all gear unit components. It requires testing rigs for testing to failure a few sets of gear drive components.
Fig. 1: Relation between operating stress spectrum and failure probability distribution Stage 2, contains extensive laboratory testing of failure probability of all gear unit components. It requires testing rigs for testing to failure a few sets of gear drive components.
In the Table 1 there are compared the most important input parameters required by Biot model, obtained within the present studies with the parameters measured by the other authors, [2, 5, 7]. Analyzing the data it is worth noticing significant difference in the tortuosity used by the other authors (about 1) and in our studies 1.5+0.4, (measured min value was 1.1 maximum 2.8).
In the Table 1 there are compared the most important input parameters required by Biot model, obtained within the present studies with the parameters measured by the other authors, [2, 5, 7]. Analyzing the data it is worth noticing significant difference in the tortuosity used by the other authors (about 1) and in our studies 1.5+0.4, (measured min value was 1.1 maximum 2.8).
Fig. 1: Comparison of SOS and nBUA from Biot’s Model and from experiments. Fig. 1 shows comparison of the SOS and nBUA obtained form the experiments and theoretical predictions of Biot’s model. There was found good correlation for the velocities (R°=0.49), while the normalized attenuations do not exhibit such behavior (R°=0.04).
Fig. 1: Comparison of SOS and nBUA from Biot’s Model and from experiments. Fig. 1 shows comparison of the SOS and nBUA obtained form the experiments and theoretical predictions of Biot’s model. There was found good correlation for the velocities (R°=0.49), while the normalized attenuations do not exhibit such behavior (R°=0.04).
Fig. 1: Sketch of experimental setup. average diameter of glass beads constituting skeleton of the material is about 260 um, while he porosity amounts 30%. Ultrasonic measurements were performed in immersion following the insertion method, [1]. The wave parameters (phase velocity and attenuation coefficient) were computed from spectrum of he broadband pulses transmitted through specimens and spectrum of the reference pulse recorded when there is no specimen between he transmitter and receiver. Experiments were done using three pairs of custom-made 10 mm- diameter unfocused ultrasonic transducers with c enter frequencies 0.5, 1, and 2 MdHz. = ransmitted signals were recorded along 2-D scans in steps of 2 mm. The radio-frequency signals were generated and acquired with 60 MHz sampling frequency, by an _ §8-bits ultrasonic programmable PC board. The scheme of the experimental setup is presented in Fig].
Fig. 1: Sketch of experimental setup. average diameter of glass beads constituting skeleton of the material is about 260 um, while he porosity amounts 30%. Ultrasonic measurements were performed in immersion following the insertion method, [1]. The wave parameters (phase velocity and attenuation coefficient) were computed from spectrum of he broadband pulses transmitted through specimens and spectrum of the reference pulse recorded when there is no specimen between he transmitter and receiver. Experiments were done using three pairs of custom-made 10 mm- diameter unfocused ultrasonic transducers with c enter frequencies 0.5, 1, and 2 MdHz. = ransmitted signals were recorded along 2-D scans in steps of 2 mm. The radio-frequency signals were generated and acquired with 60 MHz sampling frequency, by an _ §8-bits ultrasonic programmable PC board. The scheme of the experimental setup is presented in Fig].
Fig. 2: Ultrasonic images with marked ROI (square in the centre part of each image) including 441 transmitted signals for water saturated specimen at 0.5 MHz (a), 1 MHz (b) and 2 MHz (c). Figures 2a-2c present ultrasonic images obtained as the result of scan of one of the studied specimens. The images represent the ratio of magnitude of the signal transmitted through the sample to the magnitude of the reference signal transmitted through water. The images were generated for water-saturated samples at three different central frequencies of transducers (0.5, 1 and 2 MHz) and were used to define region of interest (ROI) for further studies.
Fig. 2: Ultrasonic images with marked ROI (square in the centre part of each image) including 441 transmitted signals for water saturated specimen at 0.5 MHz (a), 1 MHz (b) and 2 MHz (c). Figures 2a-2c present ultrasonic images obtained as the result of scan of one of the studied specimens. The images represent the ratio of magnitude of the signal transmitted through the sample to the magnitude of the reference signal transmitted through water. The images were generated for water-saturated samples at three different central frequencies of transducers (0.5, 1 and 2 MHz) and were used to define region of interest (ROI) for further studies.
Fig. 3. Phase velocity and attenuation of longitudinal waves in water saturated sintered glass with the average diameter of glass beads 260 wm. Transducers — 0.5, 1 and 2 MHz. and 5.8 dB/cm, respectively, and increases with frequency within the upper frequency range. When the wave parameters are found based on the method using two samples the velocity amounts around 3400 m/s and attenuation starts from about 1 dB/cm and then increases faster than the attenuations found for single samples.
Fig. 3. Phase velocity and attenuation of longitudinal waves in water saturated sintered glass with the average diameter of glass beads 260 wm. Transducers — 0.5, 1 and 2 MHz. and 5.8 dB/cm, respectively, and increases with frequency within the upper frequency range. When the wave parameters are found based on the method using two samples the velocity amounts around 3400 m/s and attenuation starts from about 1 dB/cm and then increases faster than the attenuations found for single samples.
Fig. 1: Sample of spinal cord (a) and placement of pia mater and dura mater specimens (b) Material used for investigations were samples of animal spinal cord dissected form young pigs. Healthy spinal cord was dissected from cervical part of spine and cut into samples corresponding to each cervical vertebra (fig. 1). From each sample of spinal cord samples of pia mater and dura mater were dissected. It was investigated over 140 samples dissected form 4 spinal cords — around 70 samples of dura mater and around 70 samples of pia mater. Samples were dissected both in longitudinal and perpendicular direction for each vertebra from C2 to C7. Samples were dissected also from the anterior and posterior side of spinal cord (fig. 1). All samples were mounted in special clamps with rubber inserts, which avoid over compression of samples.
Fig. 1: Sample of spinal cord (a) and placement of pia mater and dura mater specimens (b) Material used for investigations were samples of animal spinal cord dissected form young pigs. Healthy spinal cord was dissected from cervical part of spine and cut into samples corresponding to each cervical vertebra (fig. 1). From each sample of spinal cord samples of pia mater and dura mater were dissected. It was investigated over 140 samples dissected form 4 spinal cords — around 70 samples of dura mater and around 70 samples of pia mater. Samples were dissected both in longitudinal and perpendicular direction for each vertebra from C2 to C7. Samples were dissected also from the anterior and posterior side of spinal cord (fig. 1). All samples were mounted in special clamps with rubber inserts, which avoid over compression of samples.
Fig. 2: Mounting of pia mater and dura mater specimens in testing machine
Fig. 2: Mounting of pia mater and dura mater specimens in testing machine
Each characteristic can be described by three segments: first — non-linear, second — linear, third — also non-linear. Values of stress and strain for end of each characteristics segment were estimated. Each of those values was analysed for all samples and the maps of those values distribution on the surface of cervical spinal cord were prepared. Exemplary map is sresented on the fig. 4.
Each characteristic can be described by three segments: first — non-linear, second — linear, third — also non-linear. Values of stress and strain for end of each characteristics segment were estimated. Each of those values was analysed for all samples and the maps of those values distribution on the surface of cervical spinal cord were prepared. Exemplary map is sresented on the fig. 4.
For each specimen of pia mater and dura mater stress -— strain characteristics were estimated. Exemplary results for pia mater are show at fig. 3.
For each specimen of pia mater and dura mater stress -— strain characteristics were estimated. Exemplary results for pia mater are show at fig. 3.
Fig. 1: Knee-prosthesis set. Other two gauges were positioned anterior and posterior respectively, on the metal backing near the intercondylar notch. The fifth gauge was placed in the external proximal metaphysis area of the tibia. Corresponding author: spastrama @resist.pub.ro
Fig. 1: Knee-prosthesis set. Other two gauges were positioned anterior and posterior respectively, on the metal backing near the intercondylar notch. The fifth gauge was placed in the external proximal metaphysis area of the tibia. Corresponding author: spastrama @resist.pub.ro
The load of the prosthetic set during walking sequences was obtained using a complex dynamic simulator. Several pneumatic cylinders are used to simulate the loading with the weight of the trunk and the loadings due to different movements (flexion-extension, anterior- posterior translation internal-external rotation).
The load of the prosthetic set during walking sequences was obtained using a complex dynamic simulator. Several pneumatic cylinders are used to simulate the loading with the weight of the trunk and the loadings due to different movements (flexion-extension, anterior- posterior translation internal-external rotation).
5. References Fig. 3: Strain variation as a function of the flexion angle for loading mode I. The signals obtained from the strain gauges were simultaneously recorded on different channels of an amplifier. Using these recordings, two different types of curves were drawn for each loading mode: strains as a function of the flexion angle (Fig. 3) and strains as a function of the weight of the torso (Fig. 4).
5. References Fig. 3: Strain variation as a function of the flexion angle for loading mode I. The signals obtained from the strain gauges were simultaneously recorded on different channels of an amplifier. Using these recordings, two different types of curves were drawn for each loading mode: strains as a function of the flexion angle (Fig. 3) and strains as a function of the weight of the torso (Fig. 4).
Fig. 4: Strain variation as a function of the weight of the torso (Strain gauge nr. 3)
Fig. 4: Strain variation as a function of the weight of the torso (Strain gauge nr. 3)
This paper presents results from fatigue esting of bonded connection between aluminium spar and plastic composite pocket of ransport helicopter main rotor blade. Originally main rotor blade is made as full metal blade with dural spar and 21 pocket with additiona blade tip pocket made of aluminium honeycomb core and aluminium alloy skins. In order to modernize and revitalize blades o helicopter and extend operational life cycle aluminium blade pockets are replaced with plastic composite pockets with identica geometry because of their light weight and higher fatigue resistance. International aircraf building requirements prescribe strict rules for homologation of new aircraft parts. For helicopter blades and its components fatigue ife is one of the most important factors in stress analysis and fatigue testing is required in order o gain blade approval. 2. Testing procedure Testing of bonded connection between old dural spar and new composite pocket is done on test table specially designed for this occasion. Loads on outmost 21 pocket of blade are chosen for relevant loads since this part of the blade has highest local aerodynamic force. Projected operational life of blade is 2000 plus
This paper presents results from fatigue esting of bonded connection between aluminium spar and plastic composite pocket of ransport helicopter main rotor blade. Originally main rotor blade is made as full metal blade with dural spar and 21 pocket with additiona blade tip pocket made of aluminium honeycomb core and aluminium alloy skins. In order to modernize and revitalize blades o helicopter and extend operational life cycle aluminium blade pockets are replaced with plastic composite pockets with identica geometry because of their light weight and higher fatigue resistance. International aircraf building requirements prescribe strict rules for homologation of new aircraft parts. For helicopter blades and its components fatigue ife is one of the most important factors in stress analysis and fatigue testing is required in order o gain blade approval. 2. Testing procedure Testing of bonded connection between old dural spar and new composite pocket is done on test table specially designed for this occasion. Loads on outmost 21 pocket of blade are chosen for relevant loads since this part of the blade has highest local aerodynamic force. Projected operational life of blade is 2000 plus
3. Third phase of testing consists of the static verification measurement identical to those that are made in the first stage.
3. Third phase of testing consists of the static verification measurement identical to those that are made in the first stage.
Experiment results in figures 4.-6. represent vertical deflection of blade pocket trailing edge for load case without initial load. Full line shows deflection in the first phase of experiment while dotted line represents deflection in third phase after 28.420.800 cycles.
Experiment results in figures 4.-6. represent vertical deflection of blade pocket trailing edge for load case without initial load. Full line shows deflection in the first phase of experiment while dotted line represents deflection in third phase after 28.420.800 cycles.
Measurements are carried out with two indicators positioned at the middle of pocket trailing edge for measuring of vertical deflection and at trailing edge of pocket rib for measuring of tangential deflection. Fig. 3: Measurement of transverse and tangential deflections
Measurements are carried out with two indicators positioned at the middle of pocket trailing edge for measuring of vertical deflection and at trailing edge of pocket rib for measuring of tangential deflection. Fig. 3: Measurement of transverse and tangential deflections
Fig. 1: Linear stress response of critical disk part (above) with axysimmetric linear stress response of disk when it observed as blisk (down). disk When 1t obServed aS DHSK (down). According to Fig. 1 maximal equivalent SteSS Geqmax at point of expected crack initiation P (critical point) and belonging strain are unreal. It can see that critical point P corresponds to point of real crack initiation. Equivalent stress at point P’ of blisk which corresponds to critical point P of disk, taken as nominal stress o,, was served for calculation of so cold equivalent stress concentration factor Keg (Keqg=Geq(P)/On). Respecting memory of metals, real stress-strain response at critica point of disk was described by stabilized hystersis loops assigned to all simple cycles inside of engine start-stop cycles. Example of stress-strain response at critical point of the firs stage LPC rotor disk of R25-300 aero engine, for one engine start-stop cycle is shown in Fig. 2. In that figure it can see that for stress-strain response determining, cyclic stress-strain curve, Masing’s curve [2] and approximate Sonsino’s curve [1] were used. Masing’s curve was served for modelling of stabilized hysteresis loops. Equivalent stress concentration factor was used for defining of all approximate Sonsino’s curves.
Fig. 1: Linear stress response of critical disk part (above) with axysimmetric linear stress response of disk when it observed as blisk (down). disk When 1t obServed aS DHSK (down). According to Fig. 1 maximal equivalent SteSS Geqmax at point of expected crack initiation P (critical point) and belonging strain are unreal. It can see that critical point P corresponds to point of real crack initiation. Equivalent stress at point P’ of blisk which corresponds to critical point P of disk, taken as nominal stress o,, was served for calculation of so cold equivalent stress concentration factor Keg (Keqg=Geq(P)/On). Respecting memory of metals, real stress-strain response at critica point of disk was described by stabilized hystersis loops assigned to all simple cycles inside of engine start-stop cycles. Example of stress-strain response at critical point of the firs stage LPC rotor disk of R25-300 aero engine, for one engine start-stop cycle is shown in Fig. 2. In that figure it can see that for stress-strain response determining, cyclic stress-strain curve, Masing’s curve [2] and approximate Sonsino’s curve [1] were used. Masing’s curve was served for modelling of stabilized hysteresis loops. Equivalent stress concentration factor was used for defining of all approximate Sonsino’s curves.
The experiment has also been numerically tested using finite elements (FEM) [4] in order to estimate the optimum dimensions of the fluid container. At 2 MHz central frequency of the transducer, the ultrasonic beam has small variations of diameter, so that a depth of 50 mm and a diameter of 40mm for the container are sufficient.
The experiment has also been numerically tested using finite elements (FEM) [4] in order to estimate the optimum dimensions of the fluid container. At 2 MHz central frequency of the transducer, the ultrasonic beam has small variations of diameter, so that a depth of 50 mm and a diameter of 40mm for the container are sufficient.
3. Experimental setup
3. Experimental setup
The acquired signals are presented in fig. 4 and indicate a dispersed signal due to the presence of small particles in the fluid. There are many parameters influencing the phenomenon, so that numerous experiments are required for a direct indication of the dispersed particles properties such as mean size and relative particle density.
The acquired signals are presented in fig. 4 and indicate a dispersed signal due to the presence of small particles in the fluid. There are many parameters influencing the phenomenon, so that numerous experiments are required for a direct indication of the dispersed particles properties such as mean size and relative particle density.
Fig. 3: 2MHz transducer immersed in water The particles of hydroxyapatite are dispersed in pure water. The concentration and particle size are two of the parameters. A 300V pulser- receiver sends ultrasonic pulses to an immersion transducer (2 MHz _ resonance frequency) which is introduced in_ the heterogeneous fluid. 4. Conclusion
Fig. 3: 2MHz transducer immersed in water The particles of hydroxyapatite are dispersed in pure water. The concentration and particle size are two of the parameters. A 300V pulser- receiver sends ultrasonic pulses to an immersion transducer (2 MHz _ resonance frequency) which is introduced in_ the heterogeneous fluid. 4. Conclusion
Fig. 4: Acquired signals in water (top) and particles in water (bottom)
Fig. 4: Acquired signals in water (top) and particles in water (bottom)
Fig. 1: General view of specimen. Experiments were made for 8 specimens shown in fig. 1. Configuration of fibres directions in 5 plies is described in Tab. 1.
Fig. 1: General view of specimen. Experiments were made for 8 specimens shown in fig. 1. Configuration of fibres directions in 5 plies is described in Tab. 1.
Corresponding author: pyrzan@ meil.pw.edu.pl
Corresponding author: pyrzan@ meil.pw.edu.pl
Fig. 2: Specimen in the stand For investigations special experimental stand shown in fig. 2 was made. Load was applied in displacement-controlled mode. The speed of displacement varied from about 1 mm/min at the beginning of loading to about 15 mm/min at the end of loading. During experiment loading force and displacement of rivet were measured.
Fig. 2: Specimen in the stand For investigations special experimental stand shown in fig. 2 was made. Load was applied in displacement-controlled mode. The speed of displacement varied from about 1 mm/min at the beginning of loading to about 15 mm/min at the end of loading. During experiment loading force and displacement of rivet were measured.
In fig. 3 relationship between displacement and load force for 1“ and 7 specimen are presented. In the figure the force in which rivet starts destroying the laminate (F,), the force of the end of the second linear part of line (F;), and the maximal value of load force (Fyn) are shown. For one group of specimens the maxima value of load force is observed for big value o displacement and the load is nearly constant increase and decrease when fibres are ripped (spec. 1“, 3 and 5"). For the second group 0 specimens the load force decrease when displacement increase (spec. 2", 4", 6", 7 and gs,
In fig. 3 relationship between displacement and load force for 1“ and 7 specimen are presented. In the figure the force in which rivet starts destroying the laminate (F,), the force of the end of the second linear part of line (F;), and the maximal value of load force (Fyn) are shown. For one group of specimens the maxima value of load force is observed for big value o displacement and the load is nearly constant increase and decrease when fibres are ripped (spec. 1“, 3 and 5"). For the second group 0 specimens the load force decrease when displacement increase (spec. 2", 4", 6", 7 and gs,
In fig. 5 views of destroyed holes are shown. It is visible, that the process of destruction for specimens is different. Laminate is most destroyed for plies with fibres parallel and perpendicular to the load direction (spec. 4" — fig. 5d; spec. 1“ — fig. 5a and spec. 3" — fig. 5c). The least destruction is visible for specimens with fibres lying at the angle of 45° to the load direction (spec. 8" — fig. 5h; spec. 7” — fig. 5g and spec. 5" — fig. 5e). For similar number of fibres oblique and parallel/perpendicular to the load direction destruction is dependent on the direction of outer plies (spec. 2" — fig. 5b and spec. 6"" — fig. Sf). Fig. 5: Destroyed holes for 1“ to 8" spec. (a to h)
In fig. 5 views of destroyed holes are shown. It is visible, that the process of destruction for specimens is different. Laminate is most destroyed for plies with fibres parallel and perpendicular to the load direction (spec. 4" — fig. 5d; spec. 1“ — fig. 5a and spec. 3" — fig. 5c). The least destruction is visible for specimens with fibres lying at the angle of 45° to the load direction (spec. 8" — fig. 5h; spec. 7” — fig. 5g and spec. 5" — fig. 5e). For similar number of fibres oblique and parallel/perpendicular to the load direction destruction is dependent on the direction of outer plies (spec. 2" — fig. 5b and spec. 6"" — fig. Sf). Fig. 5: Destroyed holes for 1“ to 8" spec. (a to h)
Fig. 4: Load force vs. displacement for 1“ specimen.
Fig. 4: Load force vs. displacement for 1“ specimen.
To make a preliminary assembly it is allowed to insert parts into the assembly without constraints. In the Assembly Design, parts can “jump” from one position to another and they can be dragged and dropped using different tools for translation and rotation. The next step in reaching the final goal was to insert the created assembly (Fig. 2) into the DMU Kinematics Simulator.
To make a preliminary assembly it is allowed to insert parts into the assembly without constraints. In the Assembly Design, parts can “jump” from one position to another and they can be dragged and dropped using different tools for translation and rotation. The next step in reaching the final goal was to insert the created assembly (Fig. 2) into the DMU Kinematics Simulator.
In this module, the first step is to define the fixed part of the mechanism. Then the joints have to be defined. 16 different types of joints are available in CATIA. Furthermore, it is necessary to assign commands to joints: mutually rotation or translation of the elements in the joint, which will move according to defined limits. The user can ask the software to analyze the mechanism (Fig. 3).
In this module, the first step is to define the fixed part of the mechanism. Then the joints have to be defined. 16 different types of joints are available in CATIA. Furthermore, it is necessary to assign commands to joints: mutually rotation or translation of the elements in the joint, which will move according to defined limits. The user can ask the software to analyze the mechanism (Fig. 3).
During mock-up design review, users do not only need to view simulated kinematics but also analyze the mechanism's consistency with the functional specifications. DMU Kinematics
During mock-up design review, users do not only need to view simulated kinematics but also analyze the mechanism's consistency with the functional specifications. DMU Kinematics
Fretting wear tests have been performed on fretting testing rig developed at the chair of mechanical engineering shown in Fig. | FE-Simulation of the rig has been performed to understand the behaviour of the rig during testing and for damage analysis of specimen. Tests have been carried out with different test configurations and as reference, steel pads in combination with grinded steel specimen have been considered. For comparison of the results, specimens have been coated with a metallic
Fretting wear tests have been performed on fretting testing rig developed at the chair of mechanical engineering shown in Fig. | FE-Simulation of the rig has been performed to understand the behaviour of the rig during testing and for damage analysis of specimen. Tests have been carried out with different test configurations and as reference, steel pads in combination with grinded steel specimen have been considered. For comparison of the results, specimens have been coated with a metallic
The evolution of COF shows that in steel- steel contact of the reference, the curve begins at a higher value than on coated contacts and then starts to increase, while coated contacts show a low coefficient of friction over the whole testing cycle. For investigation of dissipated energy during fretting testing, the Each fretting test got a special type of damage on the surface of the specimen which, in combination with analysis of the recorded test data, gives the characteristic behaviour of the different test configurations. For further interpretation of the fretting behaviour, the recorded data was used, to draw the evolution of the coefficient of friction up. The evolution of coefficient of friction uw is shown in Fig. 2.
The evolution of COF shows that in steel- steel contact of the reference, the curve begins at a higher value than on coated contacts and then starts to increase, while coated contacts show a low coefficient of friction over the whole testing cycle. For investigation of dissipated energy during fretting testing, the Each fretting test got a special type of damage on the surface of the specimen which, in combination with analysis of the recorded test data, gives the characteristic behaviour of the different test configurations. For further interpretation of the fretting behaviour, the recorded data was used, to draw the evolution of the coefficient of friction up. The evolution of coefficient of friction uw is shown in Fig. 2.
Fig.5: SEM micrography of steel and coated surface To distinguish the types of damage, the surfaces of the specimen have been examined by using scanning electron microscope. The difference can clearly be seen in Fig.5. The steel surface shows a degraded and damaged wavy Structure in contrast to the coated surface, which shows nearly no damage and just a slight degradation of the coating. So the main task is to combine the results of coefficient of friction, dissipated energy, worn volume and further, the SEM analysis of the damaged surfaces to create a guideline for fretting resistance. Therefore the wear energy density ey [kJ/mm3] was calculated for both contact configurations. The result is depicted in Fig.6. It can be seen that the coated surface shows a higher value of wear energy density than the steel surface. So at first sight, it seems
Fig.5: SEM micrography of steel and coated surface To distinguish the types of damage, the surfaces of the specimen have been examined by using scanning electron microscope. The difference can clearly be seen in Fig.5. The steel surface shows a degraded and damaged wavy Structure in contrast to the coated surface, which shows nearly no damage and just a slight degradation of the coating. So the main task is to combine the results of coefficient of friction, dissipated energy, worn volume and further, the SEM analysis of the damaged surfaces to create a guideline for fretting resistance. Therefore the wear energy density ey [kJ/mm3] was calculated for both contact configurations. The result is depicted in Fig.6. It can be seen that the coated surface shows a higher value of wear energy density than the steel surface. So at first sight, it seems
The size of the curves represents the dissipated energy so it is clear that more energy was dissipated in steel-steel contact, than in contact of steel-coating. As fretting not only depends on dissipated energy but also in combination with surface damage, the degraded surface volume was evaluated by using laser confocal microscopy. In Fig.4 the 3D view of the surfaces is shown.
The size of the curves represents the dissipated energy so it is clear that more energy was dissipated in steel-steel contact, than in contact of steel-coating. As fretting not only depends on dissipated energy but also in combination with surface damage, the degraded surface volume was evaluated by using laser confocal microscopy. In Fig.4 the 3D view of the surfaces is shown.
Fig.3: Fretting hysteresis of steel and coating friction force was plotted over the displacement as shown in Fig.3.
Fig.3: Fretting hysteresis of steel and coating friction force was plotted over the displacement as shown in Fig.3.
But taking a closer look, the difference in wear energy density is not that big, so it is very important to also have a closer look at the SEM micrographs, which confirm the higher fretting resistance of the coated surface relative to the steel surface. clear, that the higher the wear energy density, the higher is the resistance against fretting.
But taking a closer look, the difference in wear energy density is not that big, so it is very important to also have a closer look at the SEM micrographs, which confirm the higher fretting resistance of the coated surface relative to the steel surface. clear, that the higher the wear energy density, the higher is the resistance against fretting.
Fig. 1. The bridge crane - 30 m bridge, 9 t capacity 2. Measuring system
Fig. 1. The bridge crane - 30 m bridge, 9 t capacity 2. Measuring system
After installation the system (figure 2) was calibrated with loads applied to basket. The calibration was done to record answer of the strain gauges to particular loads (2, 4 or 8 tons) and evaluates calibration factors for cranes operation measurements. Fig. 2. Measuring system - strain gauges fixed to trolley structure
After installation the system (figure 2) was calibrated with loads applied to basket. The calibration was done to record answer of the strain gauges to particular loads (2, 4 or 8 tons) and evaluates calibration factors for cranes operation measurements. Fig. 2. Measuring system - strain gauges fixed to trolley structure
operation accelerations do not exceeds design values — 0.5 m/s2,
operation accelerations do not exceeds design values — 0.5 m/s2,
Fig. 5. Huber-Misses stress in the crane — load combination — Al.1
Fig. 5. Huber-Misses stress in the crane — load combination — Al.1
Fig. 1 Shape of the load paths The results were described in [3] in detail. The new own multiaxial approaches, Papuga Critical Plane (PCr) and Papuga Integral (PD methods developed for unlimited fatigue life were investigated and published in [1], and further tested in [4]. These procedures were later enlarged also for high cycle fatigue region, as the PCF criteria.
Fig. 1 Shape of the load paths The results were described in [3] in detail. The new own multiaxial approaches, Papuga Critical Plane (PCr) and Papuga Integral (PD methods developed for unlimited fatigue life were investigated and published in [1], and further tested in [4]. These procedures were later enlarged also for high cycle fatigue region, as the PCF criteria.
Fig. 2 Stochastic loadings and their
Fig. 2 Stochastic loadings and their
Fig. 1: Three variants of single strapped joint that will be compared In order to emphasize the strong influence of the design on the joints stress states, many FEAs were done. In all cases the adherends were made of aluminium 2024 T3 with the ultimate strength Ri, = 480 MPa, the modulus of elasticity E = 73000 MPa and the Poisson’s ratio v = 0.33. The adhesive was AV 119 (also known as Araldite® 2007), which have modulus of elasticity E, = 3000 MPa, the Poisson’s ratio v, = 0.34, the tensile strength o, = 70 MPa and the shear strength t, = 47 MPa.
Fig. 1: Three variants of single strapped joint that will be compared In order to emphasize the strong influence of the design on the joints stress states, many FEAs were done. In all cases the adherends were made of aluminium 2024 T3 with the ultimate strength Ri, = 480 MPa, the modulus of elasticity E = 73000 MPa and the Poisson’s ratio v = 0.33. The adhesive was AV 119 (also known as Araldite® 2007), which have modulus of elasticity E, = 3000 MPa, the Poisson’s ratio v, = 0.34, the tensile strength o, = 70 MPa and the shear strength t, = 47 MPa.
Fig. 2: Normalised stresses into the adhesive layer of single lap joint
Fig. 2: Normalised stresses into the adhesive layer of single lap joint
Tab. 1: Maximum normalised stresses in adhesive in case of joint variant b (Fig. 1)
Tab. 1: Maximum normalised stresses in adhesive in case of joint variant b (Fig. 1)
Fig. 1 Area of slope angles variations, the length of arrows and crane loads 2. Measurement of stress and deformation Measurement is performed by applying the strain gauges at a distance of 1150 mm from the point of force action which burdens console. Cross section of console with the measuring tapes arrangement is given on Figure 3.
Fig. 1 Area of slope angles variations, the length of arrows and crane loads 2. Measurement of stress and deformation Measurement is performed by applying the strain gauges at a distance of 1150 mm from the point of force action which burdens console. Cross section of console with the measuring tapes arrangement is given on Figure 3.
Fig. 4 Measured deformation values In Figure 4 is shown a diagram with measured values for the following data: -“ For this purpose method with measurement tapes — tensometry was used. Figure 2 shows arrangement of regarding to console edge.
Fig. 4 Measured deformation values In Figure 4 is shown a diagram with measured values for the following data: -“ For this purpose method with measurement tapes — tensometry was used. Figure 2 shows arrangement of regarding to console edge.
Fig. 3 Dimensions of cross section
Fig. 3 Dimensions of cross section
Fig. 5. Results of numerical analysis
Fig. 5. Results of numerical analysis
Fig. 1: Tribological system piston ring — cylinder liner
Fig. 1: Tribological system piston ring — cylinder liner
system. Fig. 2 shows the test configuration with the analogous test model ring-on-liner. The two specimen were cut out from a real component of a gas engine from GE Jenbacher GmbH & Co OHG. An important point of all investigations is the conformity between the two specimens. To guarantee the conformity, a light-gap-methodology is applied [3]. The cylinder liner is installed in a case. This case is mounted and is linearly adjustable on he heating plate. The piston ring is installed with an adapter on the driving rod. This rod applies the reciprocating movement and the 10ormal load. On the right side of the cylinder liner the lubricant (gas engine oil) is applied via drip-feed. To ensure equivalent conditions of ‘emperature in combustion engines, the cylinder liner is heated by four heating cartridges, located beneath the case.
system. Fig. 2 shows the test configuration with the analogous test model ring-on-liner. The two specimen were cut out from a real component of a gas engine from GE Jenbacher GmbH & Co OHG. An important point of all investigations is the conformity between the two specimens. To guarantee the conformity, a light-gap-methodology is applied [3]. The cylinder liner is installed in a case. This case is mounted and is linearly adjustable on he heating plate. The piston ring is installed with an adapter on the driving rod. This rod applies the reciprocating movement and the 10ormal load. On the right side of the cylinder liner the lubricant (gas engine oil) is applied via drip-feed. To ensure equivalent conditions of ‘emperature in combustion engines, the cylinder liner is heated by four heating cartridges, located beneath the case.
determination of the boundary layer and the tribofilms formed.
determination of the boundary layer and the tribofilms formed.
Fig. 4: Cylinder liner and piston ring after a long- time test
Fig. 4: Cylinder liner and piston ring after a long- time test
Fig. 1 3PB load module with Araldite B specimen a) pushing rod b) specimen c) support (Isg,, = 40 mm) d) thermocouple e) radiation shield Polymers have distinct temperature depending material properties. Characteristic material para- meters are the storage modulus E’, the loss modulus E’’ and the loss factor tandé. The Dynamic Mechanical Analyser (DMA 242 C/1/G from Netzsch GmbH Selb) is a powerful system to analyse these parameters. Different load modes are available, for example three-point-bending (3PB), tension, compression or linear shearing. In the following 3PB is used, Fig. 1.
Fig. 1 3PB load module with Araldite B specimen a) pushing rod b) specimen c) support (Isg,, = 40 mm) d) thermocouple e) radiation shield Polymers have distinct temperature depending material properties. Characteristic material para- meters are the storage modulus E’, the loss modulus E’’ and the loss factor tandé. The Dynamic Mechanical Analyser (DMA 242 C/1/G from Netzsch GmbH Selb) is a powerful system to analyse these parameters. Different load modes are available, for example three-point-bending (3PB), tension, compression or linear shearing. In the following 3PB is used, Fig. 1.
Fig. 2 Temperature and frequency dependent storage modulus and loss factor of Araldite B Measurements are performed on Araldite B specimens (50 mm x 8mmx3 mm), Fig 2. Stor- age modulus E’ and loss factor tan 6 are measured for a temperature range from 22 °C up to 150 °C under sinusoidal loading at two _ discrete frequencies | Hz and 50 Hz.
Fig. 2 Temperature and frequency dependent storage modulus and loss factor of Araldite B Measurements are performed on Araldite B specimens (50 mm x 8mmx3 mm), Fig 2. Stor- age modulus E’ and loss factor tan 6 are measured for a temperature range from 22 °C up to 150 °C under sinusoidal loading at two _ discrete frequencies | Hz and 50 Hz.
Fig. 3 Storage modulus of different polymers and composites as function of temperature
Fig. 3 Storage modulus of different polymers and composites as function of temperature
Fig. 4 Experimental set-up; a) sample coated with random pattern (50 mm x 10 mm x 0.35 mm), b) testing machine, c) cold-light source, d) CDD- Camera (1280 x 1024 pixel) of the DIC system To analyse the deformation behaviour of thin polymer foils non-destructive tensile test and digital image correlation (DIC) are combined, Fig.4. The sample is displacement-controlled loaded in a universal testing machine Z005/TN2A from Zwick GmbH & Co. Ulm up to a predefined load. This load is set to a value at which the specimen is not damaged irreversible. The defor- mation analysis is carried out by the DIC-system ARAMIS from GOMmbH Braunschweig. To get a good correlation between load and _ recorded deformation field, the image acquisition of the DIC-system is triggered by the load signal of the testing machine using an external triggerbox.
Fig. 4 Experimental set-up; a) sample coated with random pattern (50 mm x 10 mm x 0.35 mm), b) testing machine, c) cold-light source, d) CDD- Camera (1280 x 1024 pixel) of the DIC system To analyse the deformation behaviour of thin polymer foils non-destructive tensile test and digital image correlation (DIC) are combined, Fig.4. The sample is displacement-controlled loaded in a universal testing machine Z005/TN2A from Zwick GmbH & Co. Ulm up to a predefined load. This load is set to a value at which the specimen is not damaged irreversible. The defor- mation analysis is carried out by the DIC-system ARAMIS from GOMmbH Braunschweig. To get a good correlation between load and _ recorded deformation field, the image acquisition of the DIC-system is triggered by the load signal of the testing machine using an external triggerbox.
Fig.6 AFM image of a indent left by a BERKOVICH tip in a photosensitive polymer specimen mr-15050; E;r up to 4600 N/mm? (measured with CSM Ultranano- indenter from CSM Instruments Peseux) Furthermore, Ultra Nanoindentation (UNHT) is a very efficient method to determine the hardness and YOUNG’s modulus E;y values on precise posi- ions on sample surface. The CSM system used allows extreme accuracy and extremely low hermal drift. The OLIVER/PHARR method based on a BERKOVICH indenter has been applied to determine E;; from normal force versus penetra- ion depth, Fig. 6. The mechanical properties of microstructures can be described with a high loca resolution by analysing YOUNG’s modulus and hardness distribution.
Fig.6 AFM image of a indent left by a BERKOVICH tip in a photosensitive polymer specimen mr-15050; E;r up to 4600 N/mm? (measured with CSM Ultranano- indenter from CSM Instruments Peseux) Furthermore, Ultra Nanoindentation (UNHT) is a very efficient method to determine the hardness and YOUNG’s modulus E;y values on precise posi- ions on sample surface. The CSM system used allows extreme accuracy and extremely low hermal drift. The OLIVER/PHARR method based on a BERKOVICH indenter has been applied to determine E;; from normal force versus penetra- ion depth, Fig. 6. The mechanical properties of microstructures can be described with a high loca resolution by analysing YOUNG’s modulus and hardness distribution.
Fig. 5 &(x, y) strain field on the surface of a 350 um thick SU-8 sample under tensile load F = 45 N; area of interest approx. 8 mm x 8 mm
Fig. 5 &(x, y) strain field on the surface of a 350 um thick SU-8 sample under tensile load F = 45 N; area of interest approx. 8 mm x 8 mm
The outer diameter of the ring is 20 mm, inner diameter is 14 mm. Thickness of the ring is 6 mm. The diameter of the disc is 25 mm and thickness is 6 mm. There is the geometry of ring and disc test pieces with definition of necessary dimensions in the standard [5]. the time constant and equal 1500410 N. The ring is rotated through an arc of +25° at a frequency of (1 + 0.1) Hz for a given period of time (100 + 1) hours. There is distilled water using as the surrounding medium.
The outer diameter of the ring is 20 mm, inner diameter is 14 mm. Thickness of the ring is 6 mm. The diameter of the disc is 25 mm and thickness is 6 mm. There is the geometry of ring and disc test pieces with definition of necessary dimensions in the standard [5]. the time constant and equal 1500410 N. The ring is rotated through an arc of +25° at a frequency of (1 + 0.1) Hz for a given period of time (100 + 1) hours. There is distilled water using as the surrounding medium.
Fig. 2: The topography (a) and_ electrical conductivity (b) images of area | in Fig. 1. In order to verify if an increase in the contact formation of these areas Wi and 2 re spectively in their topography and Fig. 2 (a electrica and (b) de without potential is indeed mediated by the ribofilms, representative h and without the films, marked as / Fig. 1 were mapped for electrical conductivity. pict the topography and conductivity images of the region he boundary ayer.
Fig. 2: The topography (a) and_ electrical conductivity (b) images of area | in Fig. 1. In order to verify if an increase in the contact formation of these areas Wi and 2 re spectively in their topography and Fig. 2 (a electrica and (b) de without potential is indeed mediated by the ribofilms, representative h and without the films, marked as / Fig. 1 were mapped for electrical conductivity. pict the topography and conductivity images of the region he boundary ayer.
Fig. 1: Optical micrograph of a characteristic region showing a paddy structure. Areas marked | and 2 were investigated for their electrical conductivity. An optical micrograph of an area showing characteristic layer formation is shown in Fig. 1. An indent was made in order to facilitate relocation of the same area for other analysis.
Fig. 1: Optical micrograph of a characteristic region showing a paddy structure. Areas marked | and 2 were investigated for their electrical conductivity. An optical micrograph of an area showing characteristic layer formation is shown in Fig. 1. An indent was made in order to facilitate relocation of the same area for other analysis.
6. References Whereas, from Fig. 3, which depicts the electrical conductivity of the region with the paddy structure, it is c this region is electrical ear that the surface in y insulating. It is seen from the image that the conductivity is almost uniform and the magni Here as well, carried out in the simi ude being almost zero. several measurements were ar regions with the pads and it has been observed absolutely insulating in Fig. 3 (a), we see tha not as smooth as t that these regions were nature. Although from there the topography is hat in Fig. 2 (a), the corresponding electrical conductivity image shows us that the cond by the topography. uctivity is not influenced
6. References Whereas, from Fig. 3, which depicts the electrical conductivity of the region with the paddy structure, it is c this region is electrical ear that the surface in y insulating. It is seen from the image that the conductivity is almost uniform and the magni Here as well, carried out in the simi ude being almost zero. several measurements were ar regions with the pads and it has been observed absolutely insulating in Fig. 3 (a), we see tha not as smooth as t that these regions were nature. Although from there the topography is hat in Fig. 2 (a), the corresponding electrical conductivity image shows us that the cond by the topography. uctivity is not influenced
Fig. 1: Scheme of the muddle for sample preparation To simulate the real in vivo hardening conditions to design special mould, where the required pressure for cement hardening (more then 16kPa) was provided by weights, was necessary. The scheme of the muddle is presented on Fig. 1. The samples obtained from the muddle had 4x4mm cross section and were cut into 15mm length [4].
Fig. 1: Scheme of the muddle for sample preparation To simulate the real in vivo hardening conditions to design special mould, where the required pressure for cement hardening (more then 16kPa) was provided by weights, was necessary. The scheme of the muddle is presented on Fig. 1. The samples obtained from the muddle had 4x4mm cross section and were cut into 15mm length [4].
Fig. 5: Averaged bending moments of the samples prepared by different techniques Fig. 6: Averaged diffraction angles of the samples prepared by different techniques
Fig. 5: Averaged bending moments of the samples prepared by different techniques Fig. 6: Averaged diffraction angles of the samples prepared by different techniques
Fig. 3: Averaged impact energies of the cements prepared by different techniques Fig. 4: Averaged porosities of the fracture surfaces after impact strength tests
Fig. 3: Averaged impact energies of the cements prepared by different techniques Fig. 4: Averaged porosities of the fracture surfaces after impact strength tests
Traction transformers are used for a power supply of EMU (electric multiple unit) or electrical locomotive from the catenary system. They are installed on a vehicle and must be placed in an area defined by the requirements of designers due to customer specifications. Due to 00% low-flow access on the vehicle (new KONCAR’s low floor EMU), transformer shown at Fig. 1 is placed on the roof of the train. Transformer consists of active part (magnetic core and windings) and transformer tank (including accessories and cooling unit). The tank holds all transformer mass and through its structure the transformer is fixed to the vehicle. Fig. 1: CAD model of transformer for EMU trains.
Traction transformers are used for a power supply of EMU (electric multiple unit) or electrical locomotive from the catenary system. They are installed on a vehicle and must be placed in an area defined by the requirements of designers due to customer specifications. Due to 00% low-flow access on the vehicle (new KONCAR’s low floor EMU), transformer shown at Fig. 1 is placed on the roof of the train. Transformer consists of active part (magnetic core and windings) and transformer tank (including accessories and cooling unit). The tank holds all transformer mass and through its structure the transformer is fixed to the vehicle. Fig. 1: CAD model of transformer for EMU trains.
Fig. 2: Max. stresses for 3g shock in driving direction. Numerical analysis was performed by finite element method using parabolic elements with intermediate nodes. Dynamic analysis [2] was performed by using 14 different loading models. Von Mises stresses (Fig. 2) at the region where maximum values occur are presented for simulated condition that corresponds for the 3g half-time shock directed to the driving direction.
Fig. 2: Max. stresses for 3g shock in driving direction. Numerical analysis was performed by finite element method using parabolic elements with intermediate nodes. Dynamic analysis [2] was performed by using 14 different loading models. Von Mises stresses (Fig. 2) at the region where maximum values occur are presented for simulated condition that corresponds for the 3g half-time shock directed to the driving direction.
During the tests the unit was fixed to the steel platform of the shaking table by means of two plate supports. Every accelerometer was identified for each measuring position by a number (Fig. 4). During the tests the unit was in non-operating conditions. Fig. 4: Position of accelerometers during testing.
During the tests the unit was fixed to the steel platform of the shaking table by means of two plate supports. Every accelerometer was identified for each measuring position by a number (Fig. 4). During the tests the unit was in non-operating conditions. Fig. 4: Position of accelerometers during testing.
Fig. 5: Acceleration time histories at 4 positions.
Fig. 5: Acceleration time histories at 4 positions.
Time histories of measurements channels 1 and 2 are shown in diagrams (Fig. 6). Fig. 6: Half shine shock response at positions | and 2.
Time histories of measurements channels 1 and 2 are shown in diagrams (Fig. 6). Fig. 6: Half shine shock response at positions | and 2.
The strain gauges (1,5 mm base length) are placed in two arrangements, as shown in fig. 2. Five base gauges are put on all of the embossed plate pairs, and on two of them ten supplementary gauges are put besides.
The strain gauges (1,5 mm base length) are placed in two arrangements, as shown in fig. 2. Five base gauges are put on all of the embossed plate pairs, and on two of them ten supplementary gauges are put besides.
The embossment’s height is 10 mm, its diameter is 37,4 mm.
The embossment’s height is 10 mm, its diameter is 37,4 mm.
Fig. 3: Force - displacement curves. Fig.3 shows two typical force — displacement curves. The response of the specimen is almost rigid for the initial loading (2 — 3 kN). After, the behaviour changes and considered as linear. The short linear phase is followed by a nonlinear part, with gradually decreasing slope. By experimental observation, the end of the linear phase can be identified by a micro crack propagation, which leads to the appearance of the first crack on the concrete surface. After the steel plate slips, a small amount of load increase can be observed till failure.
Fig. 3: Force - displacement curves. Fig.3 shows two typical force — displacement curves. The response of the specimen is almost rigid for the initial loading (2 — 3 kN). After, the behaviour changes and considered as linear. The short linear phase is followed by a nonlinear part, with gradually decreasing slope. By experimental observation, the end of the linear phase can be identified by a micro crack propagation, which leads to the appearance of the first crack on the concrete surface. After the steel plate slips, a small amount of load increase can be observed till failure.
4. Concluding Remarks In the paper an experimental investigation of an individual embossed mechanical bond is detailed. A new test specimen is introduced to analyze the local behaviour of embossments. The basic behaviour modes are observed from the tests and the results are evaluated quantitatively. The results are used for the validation of the developed advanced numerical model for the em bossment’s behaviour. The model is to be a pplied for the analysis of embossments interaction, too.
4. Concluding Remarks In the paper an experimental investigation of an individual embossed mechanical bond is detailed. A new test specimen is introduced to analyze the local behaviour of embossments. The basic behaviour modes are observed from the tests and the results are evaluated quantitatively. The results are used for the validation of the developed advanced numerical model for the em bossment’s behaviour. The model is to be a pplied for the analysis of embossments interaction, too.
Experimental investigations or the rapezoidal profiled sheets behavior under ransverse load were conducted on two rapezoidal sheets marked T 39/250/0.7; C.0147, as shown in Figure 1. The testing was performed for the negative position of sheet, marked Sheet 1, and for the positive sheet position, marked Sheet 2, cf. Figure 2. During esting, the load was gradually applied on rapezoidal sheets by increasing to 5 cm the evel of water in the container situated above he trapezoidal sheet, cf. Figure. 3.
Experimental investigations or the rapezoidal profiled sheets behavior under ransverse load were conducted on two rapezoidal sheets marked T 39/250/0.7; C.0147, as shown in Figure 1. The testing was performed for the negative position of sheet, marked Sheet 1, and for the positive sheet position, marked Sheet 2, cf. Figure 2. During esting, the load was gradually applied on rapezoidal sheets by increasing to 5 cm the evel of water in the container situated above he trapezoidal sheet, cf. Figure. 3.
Fig. 3: Testing of the trapezoidal Sheet 1 Fig. 1: Loaded continuous beam and typical cross sections
Fig. 3: Testing of the trapezoidal Sheet 1 Fig. 1: Loaded continuous beam and typical cross sections
For the load q = 1.5 kN/m” the trapezoida sheet deflection is 35 % greater in negative position when compared to trapezoidal shee deflection in positive position. Differences obtained in the trapezoidal sheet limit load and deflection values may be explained by the fac that in case of negative trapezoidal shee position a wider zone is in compression in the area of maximum bending moment on the span. In case of positive trapezoidal sheet position, the wider zone is in compression above the bearing which would otherwise make it more stable.
For the load q = 1.5 kN/m” the trapezoida sheet deflection is 35 % greater in negative position when compared to trapezoidal shee deflection in positive position. Differences obtained in the trapezoidal sheet limit load and deflection values may be explained by the fac that in case of negative trapezoidal shee position a wider zone is in compression in the area of maximum bending moment on the span. In case of positive trapezoidal sheet position, the wider zone is in compression above the bearing which would otherwise make it more stable.
Fig. 6: Trapezoidal Sheet | after testing. Fig. 5: Load- deflection failure diagram for Sheet 2
Fig. 6: Trapezoidal Sheet | after testing. Fig. 5: Load- deflection failure diagram for Sheet 2
Fig. 7: Trapetoidal Sheet 2 in first span after testing
Fig. 7: Trapetoidal Sheet 2 in first span after testing
Fig. 1: Friction coefficient for P10 and composite shoe In the original design brake force was developed between composite block brake shoe with nearly constant friction coefficient, and wheel tread. Since composite block brake shoe has low heat transfer ability, most of the heat produced during braking was transferred to wheel. This resulted in high thermal stresses and serious wheel tread damages. Often failures jeopardised reliability of the train. After some analyses, an expert team has decided to replace composite shoes with cast iron shoes (P10). This type of shoe is commonly used on freight wagons. This change improved heat transfer and solved initial running surface damage problem. Lower average friction coefficient of P10 shoes (fig. 1), enlarged stopping distances of the train. It was necessary to increase air pressure in brake cylinder by acceptable 10%, and in that way to achieve higher friction force. This change was not
Fig. 1: Friction coefficient for P10 and composite shoe In the original design brake force was developed between composite block brake shoe with nearly constant friction coefficient, and wheel tread. Since composite block brake shoe has low heat transfer ability, most of the heat produced during braking was transferred to wheel. This resulted in high thermal stresses and serious wheel tread damages. Often failures jeopardised reliability of the train. After some analyses, an expert team has decided to replace composite shoes with cast iron shoes (P10). This type of shoe is commonly used on freight wagons. This change improved heat transfer and solved initial running surface damage problem. Lower average friction coefficient of P10 shoes (fig. 1), enlarged stopping distances of the train. It was necessary to increase air pressure in brake cylinder by acceptable 10%, and in that way to achieve higher friction force. This change was not
After several months, a new problem appeared - breaking of the connecting plate of BBU support, often combined or preceeded by breaking of the screw connection (Fig. 2), even with dangerous drop away of the BBU. 2. Analysis and Experimental Results [1]
After several months, a new problem appeared - breaking of the connecting plate of BBU support, often combined or preceeded by breaking of the screw connection (Fig. 2), even with dangerous drop away of the BBU. 2. Analysis and Experimental Results [1]
the influence of existing gaps in vertical link connection (Fig. 3) on vibrations. Second derivative of this quantity is relative acceleration, that can be used for determining dominant vibrations source. Fig. 3: Measurement points of vertical acceleration and displacement between BBU and brake shoe holder (1- wheel, 2 — shoe holder, 3 - BBU)
the influence of existing gaps in vertical link connection (Fig. 3) on vibrations. Second derivative of this quantity is relative acceleration, that can be used for determining dominant vibrations source. Fig. 3: Measurement points of vertical acceleration and displacement between BBU and brake shoe holder (1- wheel, 2 — shoe holder, 3 - BBU)
Fig. 4: BBU vibrations during different regimes of raking 4. References In fig. 4 are shown typical vibrations during oraking in the next cases:
Fig. 4: BBU vibrations during different regimes of raking 4. References In fig. 4 are shown typical vibrations during oraking in the next cases:
In case of rope bands a big safety factor usually exists, however when bands are made of metal sheets and joined with welding technology, are showing the great sensitivity to fatigue occurrences. At testing the exploitation strength an identification of loading the band from mass of the own machine is an essential problem what results from lack of possibilities of weighing individual elements of the machine without its disassembly. A self-propelled PGOT 5500 transporter is one of such machines exploited in Betchatéw lignite opencast mining. On picture 1. a machine was shown and with arrows object bands were marked.
In case of rope bands a big safety factor usually exists, however when bands are made of metal sheets and joined with welding technology, are showing the great sensitivity to fatigue occurrences. At testing the exploitation strength an identification of loading the band from mass of the own machine is an essential problem what results from lack of possibilities of weighing individual elements of the machine without its disassembly. A self-propelled PGOT 5500 transporter is one of such machines exploited in Betchatéw lignite opencast mining. On picture 1. a machine was shown and with arrows object bands were marked.
fig. 3: Natural frequency — mean section stress diagram.
fig. 3: Natural frequency — mean section stress diagram.
The method was used to bands arrowed in picture 1. Measurements were carried out in a few series, repeatable results were achieved. The instance of measured course of acceleration in horizontal direction for the band of counterweight boom and the estimated amplitude-frequency characteristics are shown on picture 4. They stated that cross-sectional tension of the band of the counterweight boom from own mass amounted about 67 MPa. The estimated value enabled to conduct the full scope of strength and fatigue calculations including additional ingredients of the loading so like the wind, lowering base, inertial forces of mass
The method was used to bands arrowed in picture 1. Measurements were carried out in a few series, repeatable results were achieved. The instance of measured course of acceleration in horizontal direction for the band of counterweight boom and the estimated amplitude-frequency characteristics are shown on picture 4. They stated that cross-sectional tension of the band of the counterweight boom from own mass amounted about 67 MPa. The estimated value enabled to conduct the full scope of strength and fatigue calculations including additional ingredients of the loading so like the wind, lowering base, inertial forces of mass
Fig. 6: Stresses range contour lines.
Fig. 6: Stresses range contour lines.
movements. The instances of results of equivalent stresses and stresses range are shown on fig. 5 and 6. Fig. 5: Huber — von Misses stresses contour lines.
movements. The instances of results of equivalent stresses and stresses range are shown on fig. 5 and 6. Fig. 5: Huber — von Misses stresses contour lines.
Fig. 1: The friction stir welded joint of aluminium 2024 T3 and the way of cutting samples no. 1, 2, 3. rotational speed of 450 r/min and tool traverse speed of 160 mm/min.
Fig. 1: The friction stir welded joint of aluminium 2024 T3 and the way of cutting samples no. 1, 2, 3. rotational speed of 450 r/min and tool traverse speed of 160 mm/min.
Fig.1. Exemplary pattern showing structural degrading symptoms (central Pomorski Bridge in Nroclaw) after 80 years of operation, magnification A300x (SEM). Ftched in 3°%%7HNOQO).. [71
Fig.1. Exemplary pattern showing structural degrading symptoms (central Pomorski Bridge in Nroclaw) after 80 years of operation, magnification A300x (SEM). Ftched in 3°%%7HNOQO).. [71
Fig.3. Kinetic fatigue fracture diagram for 40H (41Cr4 steel - heat treatment at 200°C) as a function of the energy parameter AH In the model (1), opi¢ and €g designate the cyclic yield point and critical cyclic value of deformation ¢, respectively. AH is a new criterial quantity with the [J/m*] dimension, representing the energy dissipated in each cycle of the loading spectrum. The basic advantage of that model is invariance of the diagram in relation to R ratio, and its linear character, which is illustrated at Fig. 3, by exemplary results for the 41Cr4 steel. 5. References Description of fatigue crack kinetics in the old bridge steels showing degradation symptoms (e.g. as presented in Fig 1 and 2) may prove difficult because of the material heterogeneity (large amount of impurities).
Fig.3. Kinetic fatigue fracture diagram for 40H (41Cr4 steel - heat treatment at 200°C) as a function of the energy parameter AH In the model (1), opi¢ and €g designate the cyclic yield point and critical cyclic value of deformation ¢, respectively. AH is a new criterial quantity with the [J/m*] dimension, representing the energy dissipated in each cycle of the loading spectrum. The basic advantage of that model is invariance of the diagram in relation to R ratio, and its linear character, which is illustrated at Fig. 3, by exemplary results for the 41Cr4 steel. 5. References Description of fatigue crack kinetics in the old bridge steels showing degradation symptoms (e.g. as presented in Fig 1 and 2) may prove difficult because of the material heterogeneity (large amount of impurities).
theory is applied. The entire procedure of dependability evaluation on the base of ER algorithm, the results are given and received in the linguistic form. 5. Conclusion
theory is applied. The entire procedure of dependability evaluation on the base of ER algorithm, the results are given and received in the linguistic form. 5. Conclusion
and the cone-like ring-2 from quenched and tempered carbon steel (material C45), Fig. 1. Fig. 1: Elements of tube shrinking absorber type samples
and the cone-like ring-2 from quenched and tempered carbon steel (material C45), Fig. 1. Fig. 1: Elements of tube shrinking absorber type samples
Fig. 2: Absorption couple Quasi-static investigations were performed in two phases. In the first — preforming phase, five sample pairs were compressed approximately 70mm. In this pre-deformed form (Figure 2a) absorption elements should be mounted on the front of the railway car structure.
Fig. 2: Absorption couple Quasi-static investigations were performed in two phases. In the first — preforming phase, five sample pairs were compressed approximately 70mm. In this pre-deformed form (Figure 2a) absorption elements should be mounted on the front of the railway car structure.
After the tests were completed, the recorded data was analyzed and force versus stroke diagrams was made [1]. Typical dependence of he compression force on the distance function obtained from investigations in the second phase of the experiment for three samples is presented in figure 3. The dependence is characterized by an approximately constant force value in the whole investigated region (for he distance of +05mm). Fig. 3: Force versus stroke diagram — phase II Figure 4 shows the dependence of the compression force versus displacement obtained by a dynamic test in the second impact energy absorption phase for a displacement of ~ 20mm. characterized by an approximately constant
After the tests were completed, the recorded data was analyzed and force versus stroke diagrams was made [1]. Typical dependence of he compression force on the distance function obtained from investigations in the second phase of the experiment for three samples is presented in figure 3. The dependence is characterized by an approximately constant force value in the whole investigated region (for he distance of +05mm). Fig. 3: Force versus stroke diagram — phase II Figure 4 shows the dependence of the compression force versus displacement obtained by a dynamic test in the second impact energy absorption phase for a displacement of ~ 20mm. characterized by an approximately constant
Fig. 4: Force versus stroke diagram — dynamic
Fig. 4: Force versus stroke diagram — dynamic
Fig. 5: Prototype of absorber For European railway passenger coaches, i is recommended to have a force of absorption elements between standard buffers and car structures between 1500 and 1750 KN (per end of coach) along with a maximum stroke o 135mm [2]. Having in mind that a somewha lower force and thus energy values from the se ones were obtained in this work it was necessary to optimize some dimensions of elements. Prototype of new absorber with new dimensions was made (Figure 5).
Fig. 5: Prototype of absorber For European railway passenger coaches, i is recommended to have a force of absorption elements between standard buffers and car structures between 1500 and 1750 KN (per end of coach) along with a maximum stroke o 135mm [2]. Having in mind that a somewha lower force and thus energy values from the se ones were obtained in this work it was necessary to optimize some dimensions of elements. Prototype of new absorber with new dimensions was made (Figure 5).
Tab.1: PDF hyperbolic function coefficients. Fig.1: Probability density functions of the waterborne particle size distribution, evaluated by article size counter and by morphometric method
Tab.1: PDF hyperbolic function coefficients. Fig.1: Probability density functions of the waterborne particle size distribution, evaluated by article size counter and by morphometric method
Examination results of waterborne particle size distribution, accomplished by standard optical particle counter and morphometric method in the same sample of drinking water, are comparatively shown in fig. 1.
Examination results of waterborne particle size distribution, accomplished by standard optical particle counter and morphometric method in the same sample of drinking water, are comparatively shown in fig. 1.
Fig. 1: Locomotive model In order to evaluate the resistance in track curvature and wear of wheels and track, it is necessary to determine, in operating conditions, resistance force values on individual vehicle (locomotive) sections. Numerical, graphical or experimental methods can be used to solve this problem [1-2]. This work shows results of experimental analysis of the resistance force values in track curvature on individual parts of pulling vehicle — locomotive, on a scaled-down model in HO standard 1:87, with variable axle activity arrangement (WA). The experimental research was conducted with two identical four- axle locomotives (Fig. 1). 2. Measurements
Fig. 1: Locomotive model In order to evaluate the resistance in track curvature and wear of wheels and track, it is necessary to determine, in operating conditions, resistance force values on individual vehicle (locomotive) sections. Numerical, graphical or experimental methods can be used to solve this problem [1-2]. This work shows results of experimental analysis of the resistance force values in track curvature on individual parts of pulling vehicle — locomotive, on a scaled-down model in HO standard 1:87, with variable axle activity arrangement (WA). The experimental research was conducted with two identical four- axle locomotives (Fig. 1). 2. Measurements
Similar equations can be defined for each axle activity arrangement. Thus, the set of eight linear equations has been obtained. From the aforementioned set of equations the following results, given in Fig. 2 and Fig. 3 are obtained for different curvature radii. Fig. 2: Values of resistance forces in curvature per axle for R432, R342 and R250
Similar equations can be defined for each axle activity arrangement. Thus, the set of eight linear equations has been obtained. From the aforementioned set of equations the following results, given in Fig. 2 and Fig. 3 are obtained for different curvature radii. Fig. 2: Values of resistance forces in curvature per axle for R432, R342 and R250
‘ig. 3: Validation of experimental and analytical values of resulting resistance forces in curvature for R432, R342 and R250
‘ig. 3: Validation of experimental and analytical values of resulting resistance forces in curvature for R432, R342 and R250
a) untreated, 1000 x ~—-b) 515°C/4 hours, 1000 x Fig. 1: Influence of heat treatment on morphology of Cu-rich phases (Al-Al,Cu-Si), etch. HNO;
a) untreated, 1000 x ~—-b) 515°C/4 hours, 1000 x Fig. 1: Influence of heat treatment on morphology of Cu-rich phases (Al-Al,Cu-Si), etch. HNO;
Melting process of Al-Al,Cu-Si particles has A stages: after 2 - 4 hours is observed initiation
Melting process of Al-Al,Cu-Si particles has A stages: after 2 - 4 hours is observed initiation
Fig. 2: Changes of average area Cu-rich phase’s during the heat treatment Fig. 2 shows the average area of Al-Al,Cu- Si phase obtained in solution heat treated samples. It is evident that heating at tempera- tures below the final solidification temperature (505°C, 515°C and 525°C) results in a dissolu- tion of Al-AlCu-Si phase. Dissolution is accelerated as soon as the holding time is increased to 4 hours, where the dissolution exhibits a relatively linear behaviour with holding time. Further heating does not bring about much change in the amount or average area of Cu-phases. Maximum surface of cooper intermetallic phases was observed by 525 °C with holding times 2 hours (9995.5 um’). Minimum surface was observed by optimal temperature solution treatment 515°C (0.277 um’).
Fig. 2: Changes of average area Cu-rich phase’s during the heat treatment Fig. 2 shows the average area of Al-Al,Cu- Si phase obtained in solution heat treated samples. It is evident that heating at tempera- tures below the final solidification temperature (505°C, 515°C and 525°C) results in a dissolu- tion of Al-AlCu-Si phase. Dissolution is accelerated as soon as the holding time is increased to 4 hours, where the dissolution exhibits a relatively linear behaviour with holding time. Further heating does not bring about much change in the amount or average area of Cu-phases. Maximum surface of cooper intermetallic phases was observed by 525 °C with holding times 2 hours (9995.5 um’). Minimum surface was observed by optimal temperature solution treatment 515°C (0.277 um’).
Fig. 4: Influence of solution treatment on hardness of recycled AlSi9Cu3 alloy Fig. 4 shows the influence of heat treatment on the Brinell hardness. Hardness of solution treated test bars at 505 and 515°C are increased by increasing the solution temperature and time. Highest hardness was observed by temperature 515°C for times 2 hours (122 HBS). At 525°C, test bars show hardness reduction due to melting of the Al-Al,Cu-Si phase.
Fig. 4: Influence of solution treatment on hardness of recycled AlSi9Cu3 alloy Fig. 4 shows the influence of heat treatment on the Brinell hardness. Hardness of solution treated test bars at 505 and 515°C are increased by increasing the solution temperature and time. Highest hardness was observed by temperature 515°C for times 2 hours (122 HBS). At 525°C, test bars show hardness reduction due to melting of the Al-Al,Cu-Si phase.
Construction of the Plantograf V0O8 was designed with regards to minimisation of influence to the matrix measured points and maximisation of matrix point sensitivity. The matrix construction is described in a patent application [1].
Construction of the Plantograf V0O8 was designed with regards to minimisation of influence to the matrix measured points and maximisation of matrix point sensitivity. The matrix construction is described in a patent application [1].
Fig. 2: Top View — Part of Plantograf V08 Sensor
Fig. 2: Top View — Part of Plantograf V08 Sensor
measurement where the data is stored to a memory card. Fig. 3: Plantograf V08 — Sensor Matrix with Electronic Circuits
measurement where the data is stored to a memory card. Fig. 3: Plantograf V08 — Sensor Matrix with Electronic Circuits
Construction sizes are described on the Fig.4. Fig. 4: Sizes of Measured Electrodes
Construction sizes are described on the Fig.4. Fig. 4: Sizes of Measured Electrodes
Fig. 5: Measured Values of Different Electrode Types The average values from measurements are shown on the Fig.5.
Fig. 5: Measured Values of Different Electrode Types The average values from measurements are shown on the Fig.5.
The load system of the specimen contains two forces (Fz, Fy) and one torque moment (My). Fastening tools were designed for fixation of the specimen to loading set (Fig.1). Each of three actuators is connected by two joints. By reason of load system stability are all forces directed in pulling (Fig.1). Only the force in Z direction can effect also in pushing. The system of actuators control allows application of three load forces together (dependent, independent) but also allows application of individual load force (described in Tab.1).
The load system of the specimen contains two forces (Fz, Fy) and one torque moment (My). Fastening tools were designed for fixation of the specimen to loading set (Fig.1). Each of three actuators is connected by two joints. By reason of load system stability are all forces directed in pulling (Fig.1). Only the force in Z direction can effect also in pushing. The system of actuators control allows application of three load forces together (dependent, independent) but also allows application of individual load force (described in Tab.1).
Fig. 2: FEM analysis results Fz=10 kN, Fy=10 kN The FEM results are presented on the Fig.2 and Fig.3 and Tab.2. Tab. 2: Mechanical stress in critical places
Fig. 2: FEM analysis results Fz=10 kN, Fy=10 kN The FEM results are presented on the Fig.2 and Fig.3 and Tab.2. Tab. 2: Mechanical stress in critical places
Tab. 1: The actuators control system 5. Load simplification The aim of the work is to determine possible simplifications of the load system. The importance is to achieve comparative results in both cases (multi- and single-axial loading).
Tab. 1: The actuators control system 5. Load simplification The aim of the work is to determine possible simplifications of the load system. The importance is to achieve comparative results in both cases (multi- and single-axial loading).
Fig. 3: FEM analyses results Fz=17 kN 6. Conclusion In the paper is discussed experimental approach for determination of stresses by use of multi-axial load in comparison with single-axial load of tested specimen. The results show that the simplification is possible. The values of mechanical stresses (7) in critical place A are 248 MPa for multi-axial load and 249 MPa for single-axial load. In both cases is the distribution of mechanical stresses different. Taking into account symmetry of the specimen is used simplification acceptable. The results are based on theoretical method (FEM). For this reason it is important to verify these theoretical results by experimental tests.
Fig. 3: FEM analyses results Fz=17 kN 6. Conclusion In the paper is discussed experimental approach for determination of stresses by use of multi-axial load in comparison with single-axial load of tested specimen. The results show that the simplification is possible. The values of mechanical stresses (7) in critical place A are 248 MPa for multi-axial load and 249 MPa for single-axial load. In both cases is the distribution of mechanical stresses different. Taking into account symmetry of the specimen is used simplification acceptable. The results are based on theoretical method (FEM). For this reason it is important to verify these theoretical results by experimental tests.
is very welcomed due its numerical simplicity and easily scanned, but also as tool for quality control or quality assurance. Analysis usually refers only to the nominal values, which are declared by producers and do not examine allowed deviations and possible degradations during exploitation (product lifetime).
is very welcomed due its numerical simplicity and easily scanned, but also as tool for quality control or quality assurance. Analysis usually refers only to the nominal values, which are declared by producers and do not examine allowed deviations and possible degradations during exploitation (product lifetime).
Parametric analysis has taken in account the end- values (boundary) property changes of dampers in validated model for motion and acceleration of washing group. Another parametric issue is drum agitation in terms of various and common drum’s rotations. In many cases the amplitude of washing drum is in the margin of safety distance washing group/washing machine cabinet. For common friction dampers is experimentally evaluated ageing (cca. 10% of nominal value in 10 years with acceleration test) — fig. 2 and correlation of damping properties to the temperature — fig. 3.
Parametric analysis has taken in account the end- values (boundary) property changes of dampers in validated model for motion and acceleration of washing group. Another parametric issue is drum agitation in terms of various and common drum’s rotations. In many cases the amplitude of washing drum is in the margin of safety distance washing group/washing machine cabinet. For common friction dampers is experimentally evaluated ageing (cca. 10% of nominal value in 10 years with acceleration test) — fig. 2 and correlation of damping properties to the temperature — fig. 3.
4. References
4. References
The finite element method was adopted to model a specimen consisting of a volume of elasto-plastic material containing a realistic pore obtained by XCT, see Fig. 3. The volume in the vicini with solid e y of the pore was finely meshed ements, as shown in Fig. 3. A uniaxial tensile load was applied and _ the stresses and strains local to the pore determined. with respect Different orientations of the pore to the loading direction were investigated by rotation about two axes of the reference coordinate system. The assumed material parameters obtained with specific tensile tests are given in Tab. 1.
The finite element method was adopted to model a specimen consisting of a volume of elasto-plastic material containing a realistic pore obtained by XCT, see Fig. 3. The volume in the vicini with solid e y of the pore was finely meshed ements, as shown in Fig. 3. A uniaxial tensile load was applied and _ the stresses and strains local to the pore determined. with respect Different orientations of the pore to the loading direction were investigated by rotation about two axes of the reference coordinate system. The assumed material parameters obtained with specific tensile tests are given in Tab. 1.
Cast aluminum alloys are widely used in the automotive industry due to their excellent castability, corrosion resistance, and especially heir high strength-to-weight ratio. Their application for cast components subjected to dynamic loading motivates continuing study of he fatigue behavior of cast Al-Si alloys. Casting pores are the most common defects and are almost inevitable with the casting echnologies used in industry. Fatigue strength of cast aluminum heavily depends on pores formed during solidification because they favor fatigue crack initiation due to high local stress concentration, [1]. Different kinds of defects, classified as shrinkage and gas pores are shown in Fig. 1. Fig. 1: Metallographic pictures of gas and shrinkage pores in an Al-Si alloys
Cast aluminum alloys are widely used in the automotive industry due to their excellent castability, corrosion resistance, and especially heir high strength-to-weight ratio. Their application for cast components subjected to dynamic loading motivates continuing study of he fatigue behavior of cast Al-Si alloys. Casting pores are the most common defects and are almost inevitable with the casting echnologies used in industry. Fatigue strength of cast aluminum heavily depends on pores formed during solidification because they favor fatigue crack initiation due to high local stress concentration, [1]. Different kinds of defects, classified as shrinkage and gas pores are shown in Fig. 1. Fig. 1: Metallographic pictures of gas and shrinkage pores in an Al-Si alloys
Fig. 2: XCT images of gas and shrinkage pores geometries in 3D, [2]. Typical XCT reconstructed gas and shrinkage pores are respectively shown in figure 2.
Fig. 2: XCT images of gas and shrinkage pores geometries in 3D, [2]. Typical XCT reconstructed gas and shrinkage pores are respectively shown in figure 2.
Fig. 3: Finite element analyses of a gas pore A typical stress distribution on the pore surface is shown in Fig. 3. The fine mesh allows to identify stress gradients on the pore surface and below the pore surface.
Fig. 3: Finite element analyses of a gas pore A typical stress distribution on the pore surface is shown in Fig. 3. The fine mesh allows to identify stress gradients on the pore surface and below the pore surface.
n The elastic stress concentration factor (K,) defined as the ratio between the maximum Von Mises stress and the nominal stress was determined and plotted in Fig. 4 for different load directions. The average K,; is about 3 and the max K, for the most unfavorable load direction is about 3.5.
n The elastic stress concentration factor (K,) defined as the ratio between the maximum Von Mises stress and the nominal stress was determined and plotted in Fig. 4 for different load directions. The average K,; is about 3 and the max K, for the most unfavorable load direction is about 3.5.
Fig. 6: Plastic strain on the inner pore surface
Fig. 6: Plastic strain on the inner pore surface
Fig. 5: Cross-section of a gas pore than in the present 3D analysis. Results comparable to those of [3] (i.e. K=6) are obtained upon sectioning the present 3D pore and performing a 2D FE analysis (see Fig. 5).
Fig. 5: Cross-section of a gas pore than in the present 3D analysis. Results comparable to those of [3] (i.e. K=6) are obtained upon sectioning the present 3D pore and performing a 2D FE analysis (see Fig. 5).
Corresponding author: zdravko.virag@fsb.hr
Corresponding author: zdravko.virag@fsb.hr
5. References Fig. 2 Model results and measured data [2] in human (model data were A,,=2.9 cm’, L=3 cm, K=1, a =0.15, 7 =0.4, vy =0.8, 5 =10) Proposed model has been applied to the measured data in man and pig. The measured left ventricle and arterial pressure are used as input, and the calculated aortic flow is compared with measured ones in figs. 2 and 3.
5. References Fig. 2 Model results and measured data [2] in human (model data were A,,=2.9 cm’, L=3 cm, K=1, a =0.15, 7 =0.4, vy =0.8, 5 =10) Proposed model has been applied to the measured data in man and pig. The measured left ventricle and arterial pressure are used as input, and the calculated aortic flow is compared with measured ones in figs. 2 and 3.
Fig. 3 Model results and measured data [3] in pig (model data were A,,=1.6 cm’, L=1 cm, K=1, a=0.5, 2 =0.6, y =0.5, 5 =3)
Fig. 3 Model results and measured data [3] in pig (model data were A,,=1.6 cm’, L=1 cm, K=1, a=0.5, 2 =0.6, y =0.5, 5 =3)
The Fig. 1 depicts the position of six strain gages (1 - 6) placed ont are placed on boundary section. The coordinates direction of main cen section. We suppose the he specimen. The gages of the specimen cross zy are aligned with the tral axis of the cross second moments of the specimen cross section area to be J), J, and also the components of t he unknown bending moment to be M, and M, . Fig. 1: Assembly of the specimen cross section boundary with the strain gauges | to 6. Load of the specimen with the unknown bending moment components M.. M..
The Fig. 1 depicts the position of six strain gages (1 - 6) placed ont are placed on boundary section. The coordinates direction of main cen section. We suppose the he specimen. The gages of the specimen cross zy are aligned with the tral axis of the cross second moments of the specimen cross section area to be J), J, and also the components of t he unknown bending moment to be M, and M, . Fig. 1: Assembly of the specimen cross section boundary with the strain gauges | to 6. Load of the specimen with the unknown bending moment components M.. M..
Fig. 2: Representative tensile diagram of the standardized tensile specimen from Fig. 1.
Fig. 2: Representative tensile diagram of the standardized tensile specimen from Fig. 1.
Fig. 3: The sequence regression principle part in point (€i), jn). equivalent to stress in the places, where the strain gauges measure its deformation values. By transformation of the linear computation model of the tensile test with use of equations (3) we receive unbiased linear regression of this linear data section of the tensile diagram. The function values are predetermined by Young’s modulus EF as shown in Fig. 3, which can be subsequently determined from the measured values. Each level of load, which is in reality decomposed into the tension and _ bending components, is represented in this final line by several deformation values of the measurement strain gauges. The linear area of deformation is smoothly followed by nonlinear deformation part in point (jj, O4n)-
Fig. 3: The sequence regression principle part in point (€i), jn). equivalent to stress in the places, where the strain gauges measure its deformation values. By transformation of the linear computation model of the tensile test with use of equations (3) we receive unbiased linear regression of this linear data section of the tensile diagram. The function values are predetermined by Young’s modulus EF as shown in Fig. 3, which can be subsequently determined from the measured values. Each level of load, which is in reality decomposed into the tension and _ bending components, is represented in this final line by several deformation values of the measurement strain gauges. The linear area of deformation is smoothly followed by nonlinear deformation part in point (jj, O4n)-
substitution of the equations (4) to (5), as the individual threads in the material have different deformation and the different deformation corresponds to different stress level. For the unknown coefficients co, c;, C2, C3, ca there are several conditions to satisfy. First of all there are boundary conditions that the transition from linear area must be smooth — here formed as equations (6) and (7) and depicted in Fig. 3. Addition ally the force equilibrium condition (8) for the cross section area and moment equilibrium condition for the measured cross section must be fulfilled. The moment conditions (9,10) are composed in_ the independent direction of coordinates z and y of the cross section. In this system of equations, the known value is the stress on boundary of the linearized data part oj;,, the next known variable is the Young's modulus E of this data part, the cross section A and the nominal stress o — determined by the loading force F induced by the tensile machines. Additional requirement is to measure via experiment both moment components M,, My, which must be measured.
substitution of the equations (4) to (5), as the individual threads in the material have different deformation and the different deformation corresponds to different stress level. For the unknown coefficients co, c;, C2, C3, ca there are several conditions to satisfy. First of all there are boundary conditions that the transition from linear area must be smooth — here formed as equations (6) and (7) and depicted in Fig. 3. Addition ally the force equilibrium condition (8) for the cross section area and moment equilibrium condition for the measured cross section must be fulfilled. The moment conditions (9,10) are composed in_ the independent direction of coordinates z and y of the cross section. In this system of equations, the known value is the stress on boundary of the linearized data part oj;,, the next known variable is the Young's modulus E of this data part, the cross section A and the nominal stress o — determined by the loading force F induced by the tensile machines. Additional requirement is to measure via experiment both moment components M,, My, which must be measured.
Fig. 1: Thermal dilatometer for measuring of volume changes of ceramic material.
Fig. 1: Thermal dilatometer for measuring of volume changes of ceramic material.
Fig. 2: Strain temperature relationships from thermal dilatometer, the first and the second annealing of the same sample. When the specimen is annealed first time the strain-temperature curve is obtained and, at the end of annealing, the ceramic body is like immediately after firing. After getting cool, the second annealing is done. The difference between the second and the first strain-temperature curve is due to an actual degree of rehydration and correspond to an actual irreversible moisture expansion of investigated specimen. Then, the treatment by boiling in water or in steam proceeds in order to accelerated rehydration process. After that, the third annealing is conducted. The difference between the second and the third strain- temperature curve is caused by the convention value of moisture expansion.
Fig. 2: Strain temperature relationships from thermal dilatometer, the first and the second annealing of the same sample. When the specimen is annealed first time the strain-temperature curve is obtained and, at the end of annealing, the ceramic body is like immediately after firing. After getting cool, the second annealing is done. The difference between the second and the first strain-temperature curve is due to an actual degree of rehydration and correspond to an actual irreversible moisture expansion of investigated specimen. Then, the treatment by boiling in water or in steam proceeds in order to accelerated rehydration process. After that, the third annealing is conducted. The difference between the second and the third strain- temperature curve is caused by the convention value of moisture expansion.
Fig. 1: Load-displacement data of the specimen no.2 As an example, the load-displacement data of the specimen no.2 are shown in fig. 1.
Fig. 1: Load-displacement data of the specimen no.2 As an example, the load-displacement data of the specimen no.2 are shown in fig. 1.
The experimental results are shown in Tab. 1. 4. Conclusion The measured data accord with the finding of the three-point bending test executed on the same specimens [2]. Just the specimen no.5 shows the excessive values. We did not find their cause, hence we excluded it from the calculation of the mean elastic modulus. 5. Acknowledgements The research project has been supported by the research plan MSM 6840770012
The experimental results are shown in Tab. 1. 4. Conclusion The measured data accord with the finding of the three-point bending test executed on the same specimens [2]. Just the specimen no.5 shows the excessive values. We did not find their cause, hence we excluded it from the calculation of the mean elastic modulus. 5. Acknowledgements The research project has been supported by the research plan MSM 6840770012
The tests were carried out according to EN 12663.
The tests were carried out according to EN 12663.
Fig. 5: Longitudinal beam (before reinforcing) Fig. 4: Reinforced longitudinal beam
Fig. 5: Longitudinal beam (before reinforcing) Fig. 4: Reinforced longitudinal beam
Fig. 6: Longitudinal beam (after reinforcing) In table 3 is presented the stress for V7 and V8 neasuring points after reinforcing:
Fig. 6: Longitudinal beam (after reinforcing) In table 3 is presented the stress for V7 and V8 neasuring points after reinforcing:
Fig. 2: Testing of planetary gear drives in the back to back system (power circulation) Fig. 1: Testing sample: two-stage planetary gear drive
Fig. 2: Testing of planetary gear drives in the back to back system (power circulation) Fig. 1: Testing sample: two-stage planetary gear drive
in the closed back to back system. Side transmitters (Fig.2) for closing the flow of power (power circulation) are with transmission ratio 1:1. Load is realized through the realization of quasi-static load and _ elastic deformation of system before starting the test.
in the closed back to back system. Side transmitters (Fig.2) for closing the flow of power (power circulation) are with transmission ratio 1:1. Load is realized through the realization of quasi-static load and _ elastic deformation of system before starting the test.
If we define different upper limits of the accumulated strain, as shown with the cross- section plane in Fig. 1, and project the cross- section curve onto n-—q@ plane, we obtain different levels of critical angular velocity areas as shown in Fig. 2. Within the “critical area” we may expect the most intensive strain accumulation. Such diagrams may be used for predicting the expected life span of dynamically loaded polymeric products.
If we define different upper limits of the accumulated strain, as shown with the cross- section plane in Fig. 1, and project the cross- section curve onto n-—q@ plane, we obtain different levels of critical angular velocity areas as shown in Fig. 2. Within the “critical area” we may expect the most intensive strain accumulation. Such diagrams may be used for predicting the expected life span of dynamically loaded polymeric products.
Fig. 1: 3D diagram of cumulative accumulated strain, [(@,n,« = 7), as a function loading cycles, 4. References
Fig. 1: 3D diagram of cumulative accumulated strain, [(@,n,« = 7), as a function loading cycles, 4. References
Fig. 1: View of the specimen: a) general view of structure; b) denomination of contacts. Linear contacts were applied into specimens using special low resistance silver-based glue. In this test only contacts on both ends of the composite specimen (contacts 1-9, 2-8) and four contacts in the center of the specimen (contacts 4-6, 3-7) marked in Fig 1b) were used. For investigations the special experimental stand shown in fig. 2 was made.
Fig. 1: View of the specimen: a) general view of structure; b) denomination of contacts. Linear contacts were applied into specimens using special low resistance silver-based glue. In this test only contacts on both ends of the composite specimen (contacts 1-9, 2-8) and four contacts in the center of the specimen (contacts 4-6, 3-7) marked in Fig 1b) were used. For investigations the special experimental stand shown in fig. 2 was made.
special clasps made from insulating glass-epoxy composite reducing stress concentration in the specimen.
special clasps made from insulating glass-epoxy composite reducing stress concentration in the specimen.
Fig 4. shows the change of resistance for selected contacts for 2-wires method. Fig. 4: Change of resistance vs. load force for the specimen — 2-wires method. References
Fig 4. shows the change of resistance for selected contacts for 2-wires method. Fig. 4: Change of resistance vs. load force for the specimen — 2-wires method. References
Fig. 5: Change of resistance vs. load force for the specimen — 4-wires method. Fig 5. shows the change of resistance for selected contacts for 4-wires method.
Fig. 5: Change of resistance vs. load force for the specimen — 4-wires method. Fig 5. shows the change of resistance for selected contacts for 4-wires method.
Fig. 3: Load force vs. deflection for the specimen. In fig. 3 relationship between the deflection and the load force for the specimen is presented.
Fig. 3: Load force vs. deflection for the specimen. In fig. 3 relationship between the deflection and the load force for the specimen is presented.
Fig. 2: Compressive modulus of polycaprolactone as a function of degradation time
Fig. 2: Compressive modulus of polycaprolactone as a function of degradation time
Fig. 1: Product made of various polyamides by injection moulding. Two wear specimens that have 40°C temperature (just like normal injection moulds) form a rectangular gap of 0.5 mm, in which high local shear stresses and shear rates are produced just as at gates in real-injection moulds. Certain amounts of polymer melt are injected through the gap, and induce the abrasion on the surface of both specimens.
Fig. 1: Product made of various polyamides by injection moulding. Two wear specimens that have 40°C temperature (just like normal injection moulds) form a rectangular gap of 0.5 mm, in which high local shear stresses and shear rates are produced just as at gates in real-injection moulds. Certain amounts of polymer melt are injected through the gap, and induce the abrasion on the surface of both specimens.
Fig. 2: Surface morphology after 2000 shots of polyamide compounds: non-filled (left); 50w% glass fiber (right). The worn surface is shown on Figure 2. On the left, the specimen was eroded by non-filled polyamide, and the right specimen was deteriorated by polyamide compound, which contained 50 weight percent of glass fiber. In each case the photographs were taken after the first 2000 shots.
Fig. 2: Surface morphology after 2000 shots of polyamide compounds: non-filled (left); 50w% glass fiber (right). The worn surface is shown on Figure 2. On the left, the specimen was eroded by non-filled polyamide, and the right specimen was deteriorated by polyamide compound, which contained 50 weight percent of glass fiber. In each case the photographs were taken after the first 2000 shots.
Fig. 3: Wear-loss induced by various PA66 compounds as a function of injection shots.
Fig. 3: Wear-loss induced by various PA66 compounds as a function of injection shots.
Fig. 4: Wear-rate as a function of glass fiber content of the compounds.
Fig. 4: Wear-rate as a function of glass fiber content of the compounds.
Fig. 1: Plint TE77 tribometer The investigated material TPE was developed by the company SKF-Economos. A Pin-on-Plate test configuration was developed due to identify the behavior of tribological system. The tribological investigations were carried out using two different methods. The test methods were accomplished by means of Plint TE77 tribometer for high frequency and AMB tribometer for low frequency friction test. Fig. 1 shows Plint TE77 tribometer.
Fig. 1: Plint TE77 tribometer The investigated material TPE was developed by the company SKF-Economos. A Pin-on-Plate test configuration was developed due to identify the behavior of tribological system. The tribological investigations were carried out using two different methods. The test methods were accomplished by means of Plint TE77 tribometer for high frequency and AMB tribometer for low frequency friction test. Fig. 1 shows Plint TE77 tribometer.
Fig. 3: Evaluation of contact-near-temperature using finite element analysis The specimen temperature 7, was measured at the bottom of steel specimen, while the contact-near-temperature Ts is measured at a hole drilled in the steel specimen close to the contact surface between Pin and Plate. In order to evaluate the contact-near-temperature caused by a different combination of parameters, finite element analyses using the ABAQUS® were carried out in this study (Fig. 3).
Fig. 3: Evaluation of contact-near-temperature using finite element analysis The specimen temperature 7, was measured at the bottom of steel specimen, while the contact-near-temperature Ts is measured at a hole drilled in the steel specimen close to the contact surface between Pin and Plate. In order to evaluate the contact-near-temperature caused by a different combination of parameters, finite element analyses using the ABAQUS® were carried out in this study (Fig. 3).
High frequency tribological tests were conducted on a Plint TE77 tribometer with reciprocating configuration, which includes a control unit incorporating COMPEND acquisition software. Fig. 2 illustrates an image of the reciprocating test system of the TE77 tribometer.
High frequency tribological tests were conducted on a Plint TE77 tribometer with reciprocating configuration, which includes a control unit incorporating COMPEND acquisition software. Fig. 2 illustrates an image of the reciprocating test system of the TE77 tribometer.
In order to study the tribological behavior of TPEs at low frequencies, a linear tribometer was designed and constructed at Chair of Mechanical Engineering (AMB). Friction tests were conducted using a reciprocating wear machine where the TPE pin was subjected to a constant load and slides on a reciprocating bed, which was driven by a spring as an elastic member (Fig. 5).
In order to study the tribological behavior of TPEs at low frequencies, a linear tribometer was designed and constructed at Chair of Mechanical Engineering (AMB). Friction tests were conducted using a reciprocating wear machine where the TPE pin was subjected to a constant load and slides on a reciprocating bed, which was driven by a spring as an elastic member (Fig. 5).
TE77 tribometer provides sequence control of load, frequency and temperature in addition to the data of the reciprocating test system of the TE77 tribometer. The reciprocating friction tests consisted of many steps that combined different values of normal load, friction frequency and temperature. Fig. 4 shows a typical plot of measured data. fig. 4: Typical plot measured by TE77 tribometer
TE77 tribometer provides sequence control of load, frequency and temperature in addition to the data of the reciprocating test system of the TE77 tribometer. The reciprocating friction tests consisted of many steps that combined different values of normal load, friction frequency and temperature. Fig. 4 shows a typical plot of measured data. fig. 4: Typical plot measured by TE77 tribometer
Fig. 6: Typical plot measured by AMB The pin-on-plate tests using by AMB were carried out at different normal load and different roughness of counterbody. The duration of each friction test was extended to 24 hours Fig. 6 illustrates a typical plot measured by AMB.
Fig. 6: Typical plot measured by AMB The pin-on-plate tests using by AMB were carried out at different normal load and different roughness of counterbody. The duration of each friction test was extended to 24 hours Fig. 6 illustrates a typical plot measured by AMB.
To evaluate the selected materials under contact stress for different types of contact, the boundary conditions of the experiments have been varied across a large range of contact pressure and slip onditions. Table 1: test program: number of experiments investigated
To evaluate the selected materials under contact stress for different types of contact, the boundary conditions of the experiments have been varied across a large range of contact pressure and slip onditions. Table 1: test program: number of experiments investigated
The BoR-test, in Figure 1, consists in rolling hree pre-stressed balls having an aperture of "4 across a rod-shaped specimen (Material M50). Due to the presence of point contacts and he possibility of multiple rolling cycles, this est rig is generally used for highest contact pressures (up to to 7 GPa) and for highest test frequencies (up to /20 Hz). One disadvantage is he undefined slip during free rolling of the balls along the rod.
The BoR-test, in Figure 1, consists in rolling hree pre-stressed balls having an aperture of "4 across a rod-shaped specimen (Material M50). Due to the presence of point contacts and he possibility of multiple rolling cycles, this est rig is generally used for highest contact pressures (up to to 7 GPa) and for highest test frequencies (up to /20 Hz). One disadvantage is he undefined slip during free rolling of the balls along the rod.
The plasma nitrided material 3] CrMoV9 and R935 was tested up to 10° cycles in contact low cycle fatigue. The experiments were made on three different stress levels with a test frequency of /50 Hz, with maximal nominal contact pressure 5,2 GPa, 5,9GPa_ and 6,3 GPa. Figure 2: contact low cycle fatigue line of BoR- experiments
The plasma nitrided material 3] CrMoV9 and R935 was tested up to 10° cycles in contact low cycle fatigue. The experiments were made on three different stress levels with a test frequency of /50 Hz, with maximal nominal contact pressure 5,2 GPa, 5,9GPa_ and 6,3 GPa. Figure 2: contact low cycle fatigue line of BoR- experiments
The presented research work is connected to a running project NESC-VU, which is a European cooperative action in support of Warm Pre-Stressing (WPS) use in the Reactor Pressure Vessel (RPV) integrity assessment. WPS is a phenomenon which justifies, that crack does not propagate during unloading cycle in case of PTS. BZF takes part in the modelling work, where the WPS effects on J- integral should be determined. In the first stage of the project a preliminary calculation has been performed. An overview is given about finite element calculation of pre-cracked Charpy-like 3PB specimen, which has been performed to analyze the effect of WPS on fracture toughness value of RPV steel for two load cases (Load- Unload-Cool-Fracture and LCUF). Besides the calculation, material tests were also performed in different temperatures. Analyses on the specimen under WPS condition have been performed on a 18MND5 (A533B) ferritic steel. The material has been manufactured according to the RCC-M specifications by Creusot Loire Industrie in 1995. The material properties are provided by AREVA NP, France, [1]. True strain-stress curves from -150°C to 20°C are available for the calculation. These curves have been
The presented research work is connected to a running project NESC-VU, which is a European cooperative action in support of Warm Pre-Stressing (WPS) use in the Reactor Pressure Vessel (RPV) integrity assessment. WPS is a phenomenon which justifies, that crack does not propagate during unloading cycle in case of PTS. BZF takes part in the modelling work, where the WPS effects on J- integral should be determined. In the first stage of the project a preliminary calculation has been performed. An overview is given about finite element calculation of pre-cracked Charpy-like 3PB specimen, which has been performed to analyze the effect of WPS on fracture toughness value of RPV steel for two load cases (Load- Unload-Cool-Fracture and LCUF). Besides the calculation, material tests were also performed in different temperatures. Analyses on the specimen under WPS condition have been performed on a 18MND5 (A533B) ferritic steel. The material has been manufactured according to the RCC-M specifications by Creusot Loire Industrie in 1995. The material properties are provided by AREVA NP, France, [1]. True strain-stress curves from -150°C to 20°C are available for the calculation. These curves have been
Fig. 3. J-integral curves under WPS condition in case of LUC-LU cycle Fig. 4. J-integral curves under WPS condition in case of LCU-LU cycle
Fig. 3. J-integral curves under WPS condition in case of LUC-LU cycle Fig. 4. J-integral curves under WPS condition in case of LCU-LU cycle
J-integral was plotted in time during the WPS loading cycles. Result of finite element calculation and analytical solution were compared for both case (Fig. 3-4). In case of LCU preloading the residual J-value calculated by FEM is much higher, than in LUC case. The results show that the VOCALIST method is not applicable for non proportional load.
J-integral was plotted in time during the WPS loading cycles. Result of finite element calculation and analytical solution were compared for both case (Fig. 3-4). In case of LCU preloading the residual J-value calculated by FEM is much higher, than in LUC case. The results show that the VOCALIST method is not applicable for non proportional load.
Fig. 1: Servo hydraulic test procedure for hypoid gears
Fig. 1: Servo hydraulic test procedure for hypoid gears
Fig. 2: Tooth root fracture analysis The fatigue failure of a hypoid gear tooth root caused by cyclic loading starts with the crack initiation directly at the surface. In the next step a fatigue crack growth occur and discharge in the forced rupture. The fatigue fracture surface looks very fine-grained depending on the velocity of the fracture progress.
Fig. 2: Tooth root fracture analysis The fatigue failure of a hypoid gear tooth root caused by cyclic loading starts with the crack initiation directly at the surface. In the next step a fatigue crack growth occur and discharge in the forced rupture. The fatigue fracture surface looks very fine-grained depending on the velocity of the fracture progress.
Figure 2 shows the fracture surface of a hypoid gear wheel, where the initial crack was induced in the tooth root at about half of the tooth length directly at the surface. The fine- grained initial crack area A (Figure 3) is marked with an arrow. Consequently this results in a slow stable crack growth with a main direction of propagation along the length and smaller propagation into depth direction. The result is a half elliptical fine-crystalline fracture surface B1 (Figure 2). The stable crack growth is accelerated in depth and length direction and it leads to a rougher fracture surface B2. Within the area C the crack growth gets increasingly unstable and finally leads to the forced rupture D.
Figure 2 shows the fracture surface of a hypoid gear wheel, where the initial crack was induced in the tooth root at about half of the tooth length directly at the surface. The fine- grained initial crack area A (Figure 3) is marked with an arrow. Consequently this results in a slow stable crack growth with a main direction of propagation along the length and smaller propagation into depth direction. The result is a half elliptical fine-crystalline fracture surface B1 (Figure 2). The stable crack growth is accelerated in depth and length direction and it leads to a rougher fracture surface B2. Within the area C the crack growth gets increasingly unstable and finally leads to the forced rupture D.
The calculation in this standard is based on the maximum gear tooth root stress of in the critical cross section (fig. 1). Fig. 1: Calculation of the maximum stress in the tooth root via DIN 3990 Part 3 Method B
The calculation in this standard is based on the maximum gear tooth root stress of in the critical cross section (fig. 1). Fig. 1: Calculation of the maximum stress in the tooth root via DIN 3990 Part 3 Method B
Fig. 2: Definition of the critical cross section and the position of the force attack point [1] local tooth root stress is achieved. The Helix Angle Factor Ys accounts the difference of the tooth root stress between the helical gear and the equivalent spur gear which is the base of the calculation.
Fig. 2: Definition of the critical cross section and the position of the force attack point [1] local tooth root stress is achieved. The Helix Angle Factor Ys accounts the difference of the tooth root stress between the helical gear and the equivalent spur gear which is the base of the calculation.
Fig. 3: 3D-FE simulation result pictured with the maximum principal normal stress (Fy: = 5 KN) The first step in the simulation chain is the generation of the tooth shape by the software package KISSsoft. Afterwards the finite element pre-processing -— in particular the assembling of the 2D- and 3D-FE model — the solution and post-processing by the software Abaqus 6.7 CAE was accomplished. One of the 3D-FE simulation outputs is displayed in fig. 3.
Fig. 3: 3D-FE simulation result pictured with the maximum principal normal stress (Fy: = 5 KN) The first step in the simulation chain is the generation of the tooth shape by the software package KISSsoft. Afterwards the finite element pre-processing -— in particular the assembling of the 2D- and 3D-FE model — the solution and post-processing by the software Abaqus 6.7 CAE was accomplished. One of the 3D-FE simulation outputs is displayed in fig. 3.
In this work two spur-toothed gears (z=16 and z=24, m,=10mm, b=50mm) were tested. A confrontation of the analytical (DIN), experimental (SG) and numerical (3D and 2D) stress results Opo in N/mm? is shown in tab. 1. The difference Ao is referenced to the analytically calculated stresses according to DIN 3990 Part 3 Method B.
In this work two spur-toothed gears (z=16 and z=24, m,=10mm, b=50mm) were tested. A confrontation of the analytical (DIN), experimental (SG) and numerical (3D and 2D) stress results Opo in N/mm? is shown in tab. 1. The difference Ao is referenced to the analytically calculated stresses according to DIN 3990 Part 3 Method B.
Fig. 5: Test rig and the assembled tooth root For this investigation it was necessary to design a preferably stiff and easy to handle test rig. Fig. 5 shows the 3D-drawing and the spur gear, which is assembled with six strain gauges along the tooth root width. 4. Conclusions
Fig. 5: Test rig and the assembled tooth root For this investigation it was necessary to design a preferably stiff and easy to handle test rig. Fig. 5 shows the 3D-drawing and the spur gear, which is assembled with six strain gauges along the tooth root width. 4. Conclusions
For detailed consideration, a_ three- dimensional diagram with the software package MATLAB 6 was created (fig. 4). For detailed consideration, a three- dimensional diagram with the software package MATLAB 6 was created (fig. 4). Fig. 4: Position dependent maximum principal normal stress
For detailed consideration, a_ three- dimensional diagram with the software package MATLAB 6 was created (fig. 4). For detailed consideration, a three- dimensional diagram with the software package MATLAB 6 was created (fig. 4). Fig. 4: Position dependent maximum principal normal stress
To describe the influence of the anisotropy on the static material properties tensile tests were carried out. As shown in Tab. 1 the vertical orientated specimen show only minor higher static strength values, while the ultimate strain values are smaller.
To describe the influence of the anisotropy on the static material properties tensile tests were carried out. As shown in Tab. 1 the vertical orientated specimen show only minor higher static strength values, while the ultimate strain values are smaller.
Fig. 1: Different specimen position for anisotropy The specimens for the material tests were manufactured out of forged V-Shapes, as shown in Fig.1. The effect of anisotropy is characterised by different specimen orientations. Further on, the investigated specimens are turned clockwise through 45°.
Fig. 1: Different specimen position for anisotropy The specimens for the material tests were manufactured out of forged V-Shapes, as shown in Fig.1. The effect of anisotropy is characterised by different specimen orientations. Further on, the investigated specimens are turned clockwise through 45°.
Tensile/compression tests were carried out with a stress ratio of R=0. Contrary to the static tests which show only a minor difference in yield strength, the cyclic tests show an extended lifetime of about two for the horizontal orientated specimens especially significant in the high-cycle-fatigue range; see Fig. 2. 4. Influence of effective strain
Tensile/compression tests were carried out with a stress ratio of R=0. Contrary to the static tests which show only a minor difference in yield strength, the cyclic tests show an extended lifetime of about two for the horizontal orientated specimens especially significant in the high-cycle-fatigue range; see Fig. 2. 4. Influence of effective strain
Fig. 4: S/N-curves for effective strain 5. Microstructure
Fig. 4: S/N-curves for effective strain 5. Microstructure
Fig. 3: Specimen position for effective strain 4.1 Static test The specimens with high effective strain show higher values in static strength as well as a reduced ductility; see Tab. 2.
Fig. 3: Specimen position for effective strain 4.1 Static test The specimens with high effective strain show higher values in static strength as well as a reduced ductility; see Tab. 2.
Fig. 1: a) Test configuration — Ring on Disc [1], b) Detail [2] Since polymeric overlays are applied in arge-area contact systems, we designed a test methodology using a large-area system. The ring on disc test configuration used here has been described in detail in previous studies [1]. A rotating disc consisting of the coated ribomaterial is rubbed against a static steel ring. The set-up, the geometry and the surface finish are depicted in Fig. 1. Splash lubrication was used using fully formulated engine oil. Temperatures (7; and 7>) and the Coefficient of Friction (COF) were measured. Several test strategies have been developed to visualize the selected system properties. Within these tests the speed was kept constant and the loading was changed in predefined steps/periods. After the test the sliding surfaces were analysed using laser confocal microscopy (Olympus LEXT).
Fig. 1: a) Test configuration — Ring on Disc [1], b) Detail [2] Since polymeric overlays are applied in arge-area contact systems, we designed a test methodology using a large-area system. The ring on disc test configuration used here has been described in detail in previous studies [1]. A rotating disc consisting of the coated ribomaterial is rubbed against a static steel ring. The set-up, the geometry and the surface finish are depicted in Fig. 1. Splash lubrication was used using fully formulated engine oil. Temperatures (7; and 7>) and the Coefficient of Friction (COF) were measured. Several test strategies have been developed to visualize the selected system properties. Within these tests the speed was kept constant and the loading was changed in predefined steps/periods. After the test the sliding surfaces were analysed using laser confocal microscopy (Olympus LEXT).
Fig. 2: Step test (monotonic) — repeated running-in processes until system failure Fig. 2 depicts the tribometric results of a step test in which the loading was increased monotonously in steps of 1.8 MPa every 24h. With a sliding speed of 2.5 m/s one step corresponds to a sliding distance of more than 200 kilometres. The overall test duration was 3 days. The results show running-in during the first loading step. During this running-in process the measured COF and temperatures decline. This indicates the adaptation of the system to the corresponding _ tribological oading. Each increase in loading results in a recurrence of the running-in processes. At the fourth step the loading limit of the system is exceeded and the system fails due to seizure.
Fig. 2: Step test (monotonic) — repeated running-in processes until system failure Fig. 2 depicts the tribometric results of a step test in which the loading was increased monotonously in steps of 1.8 MPa every 24h. With a sliding speed of 2.5 m/s one step corresponds to a sliding distance of more than 200 kilometres. The overall test duration was 3 days. The results show running-in during the first loading step. During this running-in process the measured COF and temperatures decline. This indicates the adaptation of the system to the corresponding _ tribological oading. Each increase in loading results in a recurrence of the running-in processes. At the fourth step the loading limit of the system is exceeded and the system fails due to seizure.
Fig. 3: Step test (periodic) - single running-in event demand of the system for re-running-in. In further experiments we also increased the duration of the low load steps to 24 h. We didn’t detect repeated running-in either.
Fig. 3: Step test (periodic) - single running-in event demand of the system for re-running-in. In further experiments we also increased the duration of the low load steps to 24 h. We didn’t detect repeated running-in either.

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