Nonlinear Dynamic Charcateristics of Vehicle Suspension System with Multi-Degrees of Freedom
Lu Shengwen,Jia Qifen,Yu Wen,Liu Xijun
(Department of Mechanics, Tianjin University, Tianjin 300072,China)

Abstract: Kinetic model of piecewise-linear nonlinear suspension system is established, the analytic solutions of suspension system with dominant and assi stant springs are derived by means of KB Method. The amplitude-frequency curves indicate that when the buffer spring clearance is appropriate, the nonlinear characteristics are very obvious and the suspension system works as a hardening spring. The effects of nonlinear spring stiffness, damp coefficient and roughness of ground on the resonance curves are further discussed. And the effects of the equivalent spring stiffness and equivalent damp coefficient and the mass of tyres on the system vibration are analyzed, thus the motion form and the characteristics of the suspension are comprehended. The amplitude-frequency curves from theoretical analysis almost agree with simulated ones. The results supply theoretical bases for parameter recognition of piecewise-linear nonlinear vibration and optimal design of stabilized region of vehicle suspension system.
Keywords: piecewiseª²linear nonlinear, vehicle suspension, nonlinear vibration, KB method, assistant spring.