五自由度随机参数结构车辆的振动响应分析

VIBRATION RESPONSE ANALYSIS OF FIVE-DEGREE-FREEDOM VEHICLE WITH STOCHASTIC STRUCTURAL PARAMETERS

为了研究路面不平度产生的随机激励对随机结构参数非线性车辆系统的振动响应的影响,建立了随机结构参数的五自由度非线性车辆模型,将模型参数均认为是随机变量,在模型轮胎和车身之间存在非线性弹簧的前提下,来研究模型在随机激励下的随机振动响应。将路面的不平整度引起的对车辆的激励看作是白噪声过程来建立力学模型。先以能量差法等效线性化处理非线性车辆系统,然后求解李雅普诺夫方程来获得平稳随机振动响应协方差矩阵,通过多次迭代得到稳定的等效线性车辆系统参数。算例计算结果表明,方法可以高效和高精度的求解非线性系统在随机过程激励下的响应。

In order to study effect that road roughness generated random excitation on the structural parameters of nonlinear vibration response of the vehicle system, random structural parameters of five- degrees-freedom nonlinear vehicle model were estabhshed, and the model parameters are considered as random variables, under the premise that between the tire and the body presence nonlinear spring to study the random vibration response of the model under random excitation. Road irregularity is considered to be a white noise process to establish the mechanical model, the nonlinear vehicle system was linearized by the energy difference method, a stationary covariance matrix for the random vibration responses was obtained by solving the Lyapunov equations, and the stable equivalent linear system parameters of vehicle were gained through iteration. The example calculation results show that this method can improve the accuracy and efficiency of computation.