Random displacement and acceleration responses of vehicles with uncertainty

Dynamic displacement and acceleration responses of cars with uncertain parameters under random road input excitations are investigated by using a quarter-car model. Based on the theory of random vibration, the vehicle's random displacement and acceleration responses are developed in time domain and frequency domain. The sprung mass, unsprung mass, suspension damping, suspension and tire stiffness are considered as random variables. The mean value, standard deviation and variation coefficient of the vehicle's natural frequencies and mode shapes are obtained by using the Monte-Carlo simulation method. The computational expressions for the numerical characteristics of the root mean square value of vehicle's random displacement and acceleration responses in the frequency domain are developed by means of the random variable's functional moment method and algebra synthesis method. The influences of the uncertainty of the vehicle's parameters on the vehicle's random responses are investigated in detail using a practical example, and some useful conclusions are obtained. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg