In order to learn the influence of various excitations on dynamic time-frequency characteristics of vehicle-track coupling system, the Hilbert-Huang Transform (HHT) based on improved Empirical Mode Decomposition (EMD) is introduced to the vibration signal analysis. Vibration signal of coupling system is firstly decomposed into intrinsic mode functions (IMFs) by improved EMD method, and then Hilbert Time-frequency-amplitude spectrum and marginal spectrum are obtained from Hilbert-Huang Transform. The simulation indicates that Hilbert-Huang Transform has higher resolution and accuracy than Fourier Transform in frequency domain and can effectively seize modulated vibration signal of coupling system caused by wheel defect and track harmonic irregularity. Nonlinear change of vertical car body acceleration varies with the wavelength and amplitude of track irregularity. The modulated component of vibration acceleration decreases with the increase of irregularity amplitude (amplitude from 2mm to 10mm, wavelength of 10m) and has nonlinear change with the increase of irregularity wavelength (wavelength from 10m to 50m, amplitude of 10mm).
CHEN Shuang-xi;LIN Jian-hui;CHEN Jian-zheng.
Time-frequency characteristics extraction of vehicle-track coupling system based on Hilbert-Huang transform[J]. Journal of Vibration and Shock, 2013, 32(5): 43-47
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