汽车多自由度悬架的非线性振动特性

以研究主、副簧组成的悬架系统出发,建立了分段线性非线性悬架系统的动力学模型,运用KB方法求出了此类系统运动的解析解。其幅频响应曲线表明,当缓冲簧间隙适当时,系统非线性特征十分明显,相当于一种缓冲器的趋硬弹簧的作用。同时讨论了非线性弹簧刚度、阻尼系数、地面不平度对共振曲线的影响,分析了轮胎的等效刚度、阻尼系数和质量对系统振动的影响,得到了此类主、副簧组成的悬架结构的运动形式及特征。由理论分析和数值计算画出的幅频特性曲线基本吻合,可为汽车悬架系统的分段线性非线性振动的参数识别、稳定区域的分析研究和优化设计提供理论依据。

Nonlinear Dynamic Charcateristics of Vehicle Suspension System with Multi-Degrees of Freedom

Kinetic model of piecewise-linear nonlinear suspension system is established,the analytic solutions of suspension system with dominant and assistant 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.