城市轨道交通高架U型梁车-轨-桥耦合振动分析

Analysis of Vehicle-Track-Bridge Coupling Vibration for the U-shaped Girder in Urban Rail Transit

基于多体动力学原理与有限元法,利用多体动力学软件Simpack建立三维车-轨-桥耦合振动仿真模型,对列车过桥时U型梁及轨道结构竖向和横向振动进行分析,研究扣件、板下弹性支承与桥梁支座参数对U型梁和轨道结构振动的影响,给出各参数合理取值范围。研究结果表明:列车以80 km/h的速度过桥时,1阶模态对U型梁局部振动贡献最大,且在轨道不平顺激励下,容易激发高阶模态,致使U型梁局部振动加剧;U型梁翼缘处横向振动不容忽视,且应重点关注钢轨与轨道板的竖向振动;增大扣件刚度可明显减小钢轨变形,但过大的扣件刚度会使轨道板和U梁振动加剧,建议扣件竖向刚度取值范围为20 MN/m^50 MN/m;增大板下弹性支承刚度可明显减小轨道板及钢轨的竖向变形,但过大的刚度将削弱轨道弹性,不利于减振,建议板下弹性支承竖向刚度取值范围为1.0×103MN/m^1.5×103MN/m;支座刚度在一定范围内增大可减小U梁、轨道板和钢轨的振动,但过大的刚度反而会使振动加剧,建议支座竖向刚度取值范围为3×103MN/m^4×103MN/m。

A three-dimensional model for vehicle-track-bridge coupling vibration simulation is established by Simpack code based on multi-body dynamics and finite element method.The vertical and lateral vibration of the U-shaped girder and track structure is analyzed when the train is traveling through the bridge.The influence of parameters of fasteners,elastic supports under the track plate and the supports of the girder on the vibrations of the U-shaped girder and the railroad structure is analyzed.And the reasonable range of each parameter is presented.The results show that when the train is traveling through the bridge at80km/h speed,the first order mode has the largest contribution to the local vibration of the Ugirder.Under the excitation of track irregularity,the higher order mode can be stimulated readily so that the local vibration of the U-girder aggravates.The lateral vibration at the flange of the girder cannot be ignored,and the vertical vibration of rail and track plate should be focused on.Based on the calculation results,the vertical stiffness of the fasteners should be within the range of20MN/m-50MN/m,the vertical stiffness of elastic support under the track plate should be within the range of1.0×103MN/m-1.5×103MN/m,and the vertical stiffness of support of the U-girder should be within the range of3×103MN/m-4×103MN/m.