车致'站桥合一'高速铁路客站随机振动分析

摘要

为研究轨道不平顺引起的列车-"站桥合一"客站耦合系统随机振动特征,提出基于虚拟激励法和有限元方法的车辆-轨道-客站耦合系统竖向随机振动模型.其中,车辆采用具有二系悬挂的质量-弹簧-阻尼系统模拟,轨道-客站采用有限元方法模拟,轮轨关系采用可以考虑轮轨相对变形的线性Hertz接触模型.采用虚拟激励法将轨道不平顺精确地转化为一系列竖向简谐不平顺的叠加,将非平稳随机振动问题转化为确定性的时间历程问题,推导车辆-轨道-客站耦合时变系统随机振动计算模型.以天津西站为例,对列车高速通行引起的客站各楼层随机振动特性进行分析,并讨论车致振动随车速的变化规律.研究结果表明:客站竖向位移主要受车辆轴重引起的确定性激励控制,轨道不平顺引起的随机激励对其影响很小,而竖向加速度则受两种激励的双重影响;车致随机振动在客站结构内衰减迅速,同一楼层平面内,确定性响应和随机性响应衰减速率相近,沿楼层高度方向,随机性响应衰减速率稍大于确定性响应;车速变化对客站位移影响较小,但对加速度影响显著,其中加速度均方根随车速增大而显著增加.%In order to study the track irregularity-induced random vibration characteristics of the coupled system between the train and railway stations with"integral station-bridge system",a vertical random vibration model of train-track-station coupled system based on pseudo-excitation method and finite element method was pro-posed.The vehicle was simulated by mass-spring-damper system with two-layer suspension systems,and the track-station was simulated by finite element method while the wheel/rail interaction was simulated by linear Hertz contact considering the relative deformation of wheel and rail.The Pseudo-excitation method (PEM)was used to transform the vertical track profile irregularity into the superposition of harmonic excitations,and to transformthe non-stationary random vibration problem into a deterministic time history problem.Based on this,a random vibration calculation model of the train-track-station time-varying coupled system was deduced. In the case of the Tianjin West Railway Station,the random vibration characteristics of each floor of the station caused by the high-speed train operation were analyzed and the variation of the vehicle-induced vibration under various train speeds was discussed.The results show that the vertical displacement of the station is mainly con-trolled by deterministic excitation caused by vehicle axle load and the random excitation caused by track irregu-larity has little influence on the displacement,while the vertical acceleration is affected by both kinds of excita-tions.The vehicle-induced random vibration attenuates rapidly within the station structure.On the same floor, the attenuation rate of deterministic response and random response is close,and along the direction of station height,the attenuation rate of random response is slightly greater than the deterministic response.The train speed change has a minor effect on the displacement of the station but a great effect on the acceleration,with significant increase of the RMS of the accelerationwith the increase of the speed.