Non-stationary Random Vibration Analysis of Vehicle with Fractional Damping

The viscoelastic damping is one of key factors that affect vehicle vibration. It has been demonstrated that fractional derivative model can accurately model this kind of frequency dependence damping very well. Generally, the excitation of rough road can be acted as a stationary random vibration process in time domain when a vehicle is traveling at constant speeds. But the road roughness should be considered as a non-stationary random vibration process when traveling at variable speeds. In this paper, the vehicle non-stationary process is investigated by using the fractional damping model. The road roughness is built using PSD (power spectral density) in space domain by Laplace transform. The proposed method is validated by simulating a vehicle running with variable speeds in time domain. The vehicle non-stationary random response in frequency domain are also acquired by FFT( Fast Fourier Transform) algorithm.