Abstract: In this paper,an ellipse-like function is defined firstly,then a dynamic model for nonlinear hysteretic vibration isolation system is proposed by using such function,and the practical expression of the system is deduced.The dynamic model is constructed by nonlinear stiffness and nonlinear hysteretic damping,all of the parameters in the model have specific meanings,the stiffness coefficients reflect the linear and nonlinear characteristics,and the damping function describes the hysteretic and dissipative characteristics of the vibration isolation system perfectly.The dynamic model contains a parameter called damping component function,which describes all kinds of damping components probably existing in the vibration isolation system,such as friction damping,viscous damping and high-order one etc.Hence,the dynamic model can describe the hysteretic and dissipative characteristics more precisely;simultaneously,the term of nonlinear hysteretic damping force in the dynamic model is expressed as the function of displacement,thus the model proposed in this paper decreases amount of measuring work,and simplifies the process of numerical calculations.The restoring force vs.displacement loops of the vibration isolation system are reconstructed by using the dynamic model proposed in this paper.The results show that the theoretic loops agree well with the corresponding experimental loops.

Key words: dynamic model, nonlinear hysteretic vibration isolation system, ellipse-like function, damping