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The vibrodiagnostic system VDS-UT2 for the investigation of a tram wheel operational vibration and deformation
Pešek, Luděk ; Vaněk, František ; Balda, Miroslav ; Procházka, Pavel ; Vaněk, Petr ; Cibulka, Jan ; Bula, Vítězslav
The system consists of both measuring, acquisition and processing tools for monitoring of tram wheel and wheel set operational parameters,e.g.static and dynamic deformation, displacement, velocity, acceleration and temperature. The measuring on the rotating wheel is realized both by telemetric and by time difference system. Measured data can be remote observed via internet connection with the control PC. Tha acquisition system by Starmans s.r.o provides continuous analog and digital data collection. The control PC processes digital logical signals and evaluates time intervals representing circumferential turning angles between disk and rim. In the contribution the diagnostic system is described and the measured data with damage analysis are presented.
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Měření, analýza a zlepšení hlukových vlastností železničních dvojkolí
Boháč, T. ; Šeděnka, M. ; Smutný, J. ; Pazdera, L. ; Pešek, Luděk
Within the long-term development of railway wheels with vibration and noise absorbers manufactured in the Bonatrans Group a.s., their numerical modelling is in process as well as their dynamic and vibro-acoustic testing in laboratories and in operation. This article provides a brief description of the methodology of operational measurements of the railway wheels noise with and without absorbers including the results obtained on the basis of the analyses of the measurements in the underground in Boston and Prague and on the test ring of the reference track in Cerhenice. The effectiveness of the applied absorbers resulting in reduction of the noise of moving vehicles on various tracks during various travelling modes is evident from the results.
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Properties of thermo-visco-elastic material 42-809 for vibro-damping segment production - 3.part
Svoboda, J. ; Pešek, Luděk ; Frölich, V. ; Klášterka, Petr
The mechanical properties of rubber elements made of thermo-visco-elastic material 42 -809 at low temperatures are summarized in the report. The tests were performed in a climate chamber bought by company INOVA Prague. The chamber was built in a fatigue machine INSTRON 8502 and the temperature range is from -50 up to 180 C. For improvement of a measurement accuracy and loading the force cell with a range up to 40kN was installed. The original sample fixtures of the machine were substituted by two rods ending by supporting plate. The rods went through the bottom and top lids of the chamber. The results of static and dynamic characteristics for temperature from -50 to 0 C, measurement of residual deformation and relaxation time, evaluation of a cyclic loading influence on static characteristics and life-time characteristics for lower temperature are herein presented.
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Properties of thermo-visco-elastic material 42-809 for manufacturing of vibrodamping elements – 3.part
Svoboda, Jaroslav ; Pešek, Luděk ; Frölich, V. ; Klášterka, Petr
In the report the results of rubber elements properties made of thermo-visco-elastic material 42-809 at low temperatures are summariesed. The tests were performed by a loading fatigue machine INSTRON 8502 in a climate chamber. For improving an accuracy of measurement the test machine was equipped with a lesser force transduser Rumburk with a range up to 40kN. The report includes results of static and dynamic characteristics in temperature range 0 ÷ -50°C, measurement of residual deformations, relaxation time and evaluation of a cyclic loading influence to shapes of static characteristics of the rubber. Furthermore the results of rubber element life time and evaluation of friction behaviour at lower temperatures are presented. The limit lines for 10% of residual deformations are drawn here, too.
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MKP 3D MODELOVÁNÍ TEPELNÝCH DĚJŮ TLUMÍCÍCH PRVKŮ S TERMO-MECHANICKOU VAZBOU
Pešek, Luděk ; Šulc, Petr
The COMSOL code based on weak formulation of PDE's problem was used for solution of thermo-mechanical interaction in pre-pressed rubber segment used for resilient elements of the composed tram wheels. For computational time efficiency the structural and heat field are decomposed and the balance of heat power density and dissipation power density realizes the coupling. The dissipation power is computed according to the assumed proportional damping model. The results of thermo-mechanical processes for press and shear deformations under static pre-pressed and cyclic dynamic loading are presented and analyzed.
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Properties of thermo-visco-elastic material 42-809 for vibro-damping segment production
Svoboda, J. ; Pešek, Luděk ; Frölich, V. ; Klášterka, Petr
The mechanical properties of rubber elements made of thermo-visco-elastic material 42 -809 at low temperatures are summarized in the report. The tests were performed in a climate chamber bought by company INOVA Prague. The chamber was built in a fatigue machine INSTRON 8502 and the temperature range is from -50 up to 180 C. For improvement of a measurement accuracy and loading the force cell with a range up to 40kN was installed. The original sample fixtures of the machine were substituted by two rods ending by supporting plate. The rods went through the bottom and top lids of the chamber. The results of static and dynamic characteristics for temperature from -50 to 0 C, measurement of residual deformation and relaxation time, evaluation of a cyclic loading influence on static characteristics and life-time characteristics for lower temperature are herein presented.
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Teplotní účinek na rheologické vlastnosti pryžového prvku
Půst, Ladislav ; Pešek, Luděk ; Vaněk, František ; Bula, Vítězslav
Deformation and temperature data of a vibro-damping element measured in laboratory condition at harmonic loading with constant prload F st =6kN were elaborated with the aim to build termo-mechanical characteristic of rubber-like material. It is shown that the increase of temperature during harmonic loading at various amplitudes F0=(0,75,3) kN and frequencies fe(10,30) Hz is exponential in time and proportional to the square of loading amplitude. The proposed mathematical model of dynamic characteristic of specimen gained by the regression procedure consists of linear, quadratic and fourth root function of displacement amplitude Xo and of the linear correction function of temperature.
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Measurement and analysis of tram wheel vibration at riding on track
Pešek, Luděk ; Vaněk, František ; Cibulka, Jan ; Vaněk, P. ; Boháč, T.
In the contribution the design, realization and results of vibro-acoustic measurements on the riding tram wheel is presented. The operational tests were performed on the tram KT8D5 of DPMB Brno. The tram wheel with a special rubber padding design was equiped with add-on vibro-acoustic dampers. Efficiency of the add-on dampers was evaluated from comparison tests on the tram wheel with and without these dampers. Third octave and time-frequency analysis of the measured vibro signals is herein presented for a bow track passage. For analysis of operational vibration modes the FE model of the wheel with add-on dampers was developed and applied.
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