轨道不平顺导致的车桥耦合振动分析

研究目的：轨道不平顺常常是激起车桥系统耦合振动的主要因素之一，通过研究轨道不平顺导致的车桥耦合振动规律，为铁路桥梁精确设计提供理论依据。 研究方法：以H．Hamid等人提出的轨道不平顺功率谱密度为例，构造了时域内的轨道随机不平顺函数。以轨道不平顺样本函数为激振源，通过求解车桥系统耦合振动微分方程，分析铁路桥梁在列车荷载作用下的动力响应规律。 研究结果：计算了广西红水河铁路斜拉桥在列车通过时的动力响应，给出了不同车速及不同不平顺样本函数情况下桥梁主跨中点横向位移时程曲线。 研究结论：桥梁结构动力响应主要随车速及不平顺样本函数的不同而变化，且有较大的随机性。对于广西红水河铁路斜拉桥，桥梁主跨中点的最大横向位移一般在车速为75～95km／h时达到最大。

Analysis of Vehicle-bridge Coupled Vibration due to Track Irregularities

Research purposes: Track irregularity is usually one of the most important factors that induce vehicle-bridge coupled vibration.Studying the laws of vehicle-bridge coupled vibration due to track irregularity can better provide(theoretical) basis for precise design of(railway) bridges.Research methods:Track random irregularity functions in time domain are established on the basis of H.Hamid's(Power) Spectrum Density(PSD) functions of track irregularities.The track irregularity sample functions are taken as(exciting) source to solve vibration differential equations of vehicle-bridge coupled vibration.This paper also studies the(dynamic) characteristics of railway bridges under moving vehicles.Research results:The Hongshui River railway cable-stayed bridge in Guangxi is taken as example to calculate the(dynamic) response of the bridge under train passage,and the curves of time history of displacement at midpoint of bridge main span for different vehicle velocities and irregularity samples.Research conclusions:The dynamic response of the bridge due to passing trains is related to the speed of train and the change of track irregularity samples,and it is of random characteristics.For the Hongshui River railway cable-stayed bridge,the speed at which the largest lateral displacements occur falls between 75 km/h and 95 km/h.