Vibration Response of Vehicle with Stochastic Structural Parameters under Random Excitation

To investigate the influence of random structure parameters on vehicle vibration responses, the random vibration responses of a vehicle system with uncertain parameters under random road excitations were investigated using a quarter-vehicle model. A dynamic model for the system was established. In this model, sprung mass, unsprung mass, suspension damping, suspension and tyre stiffness are considered as random variables, springs between tires and vehicle body are thought to be nonlinear, and road irregularity is considered to be a white noise process. 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 iterations. The example calculation results show that this method can improve the accuracy and efficiency of computation—the relative error of displacement is 6.841 5% to the energy difference method, while it is 8.150 5% to the equation difference method; solving the variance value of random responses using the energy difference method uses only 0.8 s, and while simulating 1 000 times using the Monte Carlo method 70 min.