基于改进的EMD方法提取车辆-轨道垂向耦合系统动态特性

Dynamic characteristics extraction of vehicle-track vertically coupling system based on improved EMD

提出利用一种改进的经验模态分解(EMD)方法提取车辆-轨道耦合系统的动力学特性。该方法以改进的极值域均值代替极值点包络线的均值来提高局部均值的求解精度,以边界波形匹配预测法来抑制端点效应。基于车辆-轨道耦合动力学理论,建立客车-弹性支承块无砟轨道垂向耦合动力学模型,计算车辆-轨道耦合系统在波浪形磨损和轨道不平顺组合激励模型下的振动响应。运用改进的EMD方法对系统的振动响应进行经验模态分解,并且对轮轨力、转向架和车体加速度的本征函数进行分析和比较。研究结果表明:改进的EMD方法自适应地将振动响应分解成本征函数,能有效地提取车辆-轨道耦合系统的动力学特性。

In order to extract dynamic characteristics of vehicle-track coupling system, the method of improved empirical mode decomposition （IEMD） was presented. In the method, the field mean of extrema was adopted instead ot the points envelope mean and the boundary wave matching algorithm was used to restrain the end effect. Based on the theory of vehicle-track coupling dynamics, the vehicle ballastless-track vertically coupling dynamics model ~a.~ established. With the rail corrugation and rail irregularity excitation model, dynamic responses of vehicle-track coupling system were calculated at different driving speed. The dynamic responses were decomposed by IEMD, and then ｜he intrinsic mode functions of vertical contact force, bogie acceleration, and car body acceleration were analyzed and compared. The results show： the IEMD can self-adaptively decompose vibration signals to intrinsic mode tunetions and so effectively extract dynamic characteristics of vehicle-track coupling system.