基于希尔伯特-黄变换提取车桥耦合系统时频特性

摘要

Hilbert-Huang transformation ( HHT) based on improved empirical mode decomposition ( EMD) was introduced to analyse vibration signals of a vehicle/track/bridge coupled system. Based on the theory of coupling dynamics, the dynamic response of coupled system with high speed motor car moving on bridge was calculated before and after wheel tread reprofiling, respectively. Vibration signals of coupled system were decomposed into intrinsic mode functions (IMFs) by improved EMD method, and then Hilbert marginal spectrum was achieved by HHT. The simulation indicates that Hilbert marginal spectrum has higher resolution than Fourier amplitude spectrum in frequency domain and the proposed method is effective in the time-frequency characteristics extraction of vehicle/track/bridge coupled system.%将一种基于改进经验模态分解( EMD)的希尔伯特-黄变换(Hilbert-Huang Transform)方法,应用于车辆-轨道-桥梁耦合动力学的振动信号分析中.基于车辆-轨道-桥梁耦合动力学理论,仿真计算轮对踏面修形前后高速动力车过桥时耦合系统的动力响应.运用改进EMD方法提取振动信号的固有模态函数(IMF),再对固有模态函数进行希尔伯特-黄变换,得到时频幅值谱和边缘谱.计算结果表明:Hilbert边缘谱比傅里叶幅值谱具有更高分辨率,为车辆-轨道-桥梁耦合系统时频特性提取提供了一种有效的分析手段.