车桥系统共振机理和共振条件分析

通过理论推导和分析实例研究列车以一定速度通过桥梁时，车桥系统的共振机理和发生共振的条件。根据发生机理的不同，车桥系统可能发生几种不同形式的共振，包括由车辆重量、离心力、横向平均风荷载等形成移动荷载列的周期性动力作用引起的桥梁共振，由移动荷载列加载速率引起的桥梁共振，由轨道不平顺、车轮扁疤、轮对蛇行等周期性加载引起的桥梁共振；由桥跨的规则性排列及其挠度的影响，对移动车辆形成周期性动力作用使车辆出现的共振。车桥系统的共振条件与桥梁跨度、长度及竖向和横向刚度，列车编组、车辆轴距参数及车辆的自振频率等因素有关。

Analysis of Resonance Mechanism and Conditions of Train-Bridge System

The resonance mechanism and conditions of the train-bridge system under moving trains are studied through theoretical derivations and example analyses. According to different mechanisms, there exist several types of resonance, including the bridge resonance induced by the periodical actions of moving load series of the weights, centrifugal forces and lateral winds of vehicles, the bridge resonance induced by the loading rates of moving load series of vehicles, the bridge resonance induced by the periodical loading of train vehicles excited by rail irregularities, wheel flats and hunting movements, and the vehicle resonance induced by periodical actions of the regular arrangement of bridge spans and their deflections. The resonance conditions of the train- bridge system are affected by the span, total length, lateral and vertical stiffness of the bridge, the compositions of the train, and the axle arrangements and natural frequencies of the vehicles.