An asymmetric hysteresis model for metal-rubber isolators under dynamic loading and its application to nonlinear vibration simulation

Abstract

Metal-rubber isolators (MRIs) have been widely used to mitigate vibration in sensitive equipment due to their high damping properties. This paper aims to predict the nonlinear vibration response of an MRI system by using the hysteretic nonlinearity of a single MRI. An experimental study was conducted to investigate the effects of excitation levels on the hysteretic nonlinearities of a typical MRI. An asymmetric hysteresis model (AHM) was developed to accurately reproduce the experimental hysteresis loop by simultaneously considering the nonlinear elasticity and dry friction damping. The equivalent slip force amplitude of the MRI can be extracted from the frictional damping force to describe the slip state of the internal metal wires. Additionally, it was integrated as a constraint into parameter evolution to accurately predict the hysteretic behavior at various excitation amplitudes. The harmonic balance method (HBM) combined with alternating frequency-time (AFT) analysis was used to simulate the steady-state nonlinear vibration response of a complex MRI system. The simulation results showed good agreement with the experimental data, and indicated two major nonlinear phenomena: nonlinear softening stiffness and nonlinear damping effects. This paper developed a modeling and simulation strategy spanning from the MRI element to the system level.