VISCOUS NONLINEARITY INFLUENCE UPON INTERNAL ENERGY DISSIPATION IN CASE OF RUBBER ANTIVIBRATING ELEMENTS SUBJECTED TO A DYNAMIC HARMONIC REGIME

摘要

As a function of the internal structure of the vulcanized rubber, strengthened with black carbon, experimentally has been stated that the internal dissipated energy has high values leading to rubber degradation, while subjected to both permanent static and harmonic dynamic load. The tests have been performed under laboratory conditions upon a specialized stand so that natural scale antivibrating elements have been subjected to 20 KN dynamic forces and 50 Hz vibration frequency. In order to obtain compression, shear and compression-shear load, the location angle of the antivibrating elements has been discretely changed. Finally, a calculus model having the viscous nonlinear dumping written in terms of a power seria has been established in order to put into evidence both the high order harmonics excitation related to the imposed fundamental dynamic perturbing pulsation and the evaluation of the internal energy corresponding to high order harmonics. Also must be mentioned that the dissipated energy due to the high order harmonics is higher than the energy corresponding to the imposed fundamental dynamic perturbing harmonic, thus showing the accelerated rubber degradation.