Abstract:

According to the characteristics that road roughness is a stationary random process in the spatial domain when a vehicle is running at variable speed， a new method is proposed to solve the statistical characteristics of the non?stationary random vibration response of the vehicle. A two?degree?of?freedom single wheel model of vehicle vibration in time domain is established. Based on the transformation of variables and their derivatives in time domain and space domain， the corresponding vehicle vibration model in space domain is deduced. With the Fourier transform of spatial frequency， the spatial frequency response characteristics of vehicle vibration and the spatial frequency response characteristics of vibration response variables in time domain are established. The road grading standard is used to represent the statistical characteristics of road roughness in space domain， and the formula for calculating the statistical characteristics of non?stationary vibration response variables is established based on the spatial frequency response characteristics. The parameters of a vehicle and typical driving conditions including uniform acceleration， uniform speed and uniform deceleration are selected to analyze the variation law of statistical characteristics of non?stationary vibration response variables. The results show that the statistical characteristics of vehicle non?stationary vibration response change with the change of vehicle speed and have time?varying characteristics.

Key words: non?stationary random vibration, statistical characteristics, solution method, Fourier transform, spatial frequency response characteristics