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Behavior of thermo-visco-elastic material 42-809 for production of vibrodamping segments - Part I
Svoboda, Jaroslav ; Pešek, Luděk ; Fröhlich, Vladislav ; Vaněk, František ; Klášterka, Petr ; Cibulka, Jan
The report deals with the first results of rubber segment properties for vibrodamping of tram wheels. There are presented static and dynamic characteristics of force and deformation, changes of stiffness, temperature and loss factor with respect to number of cycles. In addition the growth of permanent deformation, lost of recovery, relaxation phenomena etc.
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Curves of equal fatigue lives under combined random stress
Svoboda, Jaroslav ; Fröhlich, Vladislav
The contribution deals with determining an influence of normal and tangential components of a stress on the total damage under combined random loading in tension-pressure and torsion. An experimental program ran with plain and notched tube specimens made out of low carbon steel ČSN 411523.1. Regression curves were obtained for several rations of standard deviations of the stress components. Basing on the regression curves, curves of equal fatigue lives were constructed. It is possible to use them for calculating asafe life of structures.
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Structure life under a multiaxial loading
Svoboda, Jaroslav ; Balda, Miroslav ; Fróhlich, Vladislav
The contribution deals with a problem of fatigue life of structures exposed to a proportional random multiaxial loading in tension - pressure and torsion. Tests proved that a fatigue damage is stronglydependent on the main stress level, while maintaining the corresponding maximum shear stress constant. The obtained fatigue-life curve as a main stress standard deviation as function of the number of loading blocks has the similar character as the S-N curve under harmonic loading.
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