Time-frequency analysis of vehicle/bridge coupling system based on Hilbert-Huang Transform

In order to investigate the change of time-frequency characteristics of vehicle/track/bridge coupling system caused by wheel tread reprofiling, a coupling model of vehicle/track/bridge system is developed, the empirical mode decomposition (EMD) and Hilbert-Huang Transformation (HHT) are introduced to the analysis of vibration signal. Based on the theory of vehicle/track/-bridge coupling dynamics, vibration acceleration of coupling system of motor car moving over bridge are calculated before and after wheel tread reprofiling, respectively. Vibration signal of coupling system is firstly decomposed into intrinsic mode functions (IMFs) by EMD method, and then Hilbert marginal spectrum is obtained from Hilbert-Huang transform. Compared with Fourier amplitude spectrum, Hilbert spectrum has higher resolution power in frequency domain in the time-frequency analysis. The simulation indicates that the proposed method is effective in the time-frequency characteristics extraction of vehicle/track/bridge coupling system.