大跨度铁路桥梁车桥空间耦合振动研究

Study on Space Dynamic Interaction Between Train and Long-Span Railway Bridge

本文系统地研究了铁路桥梁的车桥空间耦合振动问题。在详细讨论并建立桥梁、车辆、轨道以及车桥相互作用模型的基础上,提出了以轨道不平顺作为激励源的车桥空间动力响应数值计算方法。其主要特点为:(1) 结合大跨度铁路桥梁结构的特点,建立了合理的有限元空间动力分析模型。(2) 提出了适合我国铁路主型货车——C_(62)型货车的空间车辆动力模型,其特点是考虑因素比较周全(共具有27个自由度),轮轨关系以及转向架构架的弹性变形描述比较完善,因此能更切合实际地反映车辆振动特性。对照表明,在不平顺路面上动力响应的计算结果与实测结果基本吻合。本模型的建立使得车桥响应研究中的一个重要问题——车辆在振动桥面上的运行安全度(如脱轨问题)研究成为可能。(3)针对桥梁振动引起的桥面上轨道的变位,提出了轨道二次不平顺的概念,并由此建立了车辆与桥梁之间的相互作用关系。(4) 采用二次滤波法求得轨道原有不平顺的数值模拟。(5) 根据所建立的车桥相互作用模型,提出了一个新的车桥动力方程迭代去耦解法,可以比原有方法大大节省计算机时,从而使得在小型计算机或微型计算机上实现整列车通过太跨度桥梁的全过程的仿真计算成为可能。根据实际桥梁的仿真结果,本文研究了不同车速、不同轨面不平顺下的车桥耦合动力特性、机车与列车过桥引起的响应差别以及轨面二次不平顺对车辆系统的影响。

The problem of space dynamic interaction between train and railway bridge is studied systematically in this thesis. At first, calculating models for bridge, vehicle, track, and vehicle-bridge interaction are established and discussed in detail. Based on these models, a numerical method for vehicle-bridge space dynamic response has been developed, taking track irregularities as the exciting source. The main features of this paper can be presented as follows:——A rational space dynamic model of finite element structural analysis is established for long-span bridges.——A 27-DOF vehicle space-model for C82 Freight Car, the main type used in China, is developed, in which the wheel-track interaction and the elastic deformation of the truck frame are fully described. The calculation results of the dynamic response with track irregularities are compared with measured results and good agreement is achieved.This vehicle model makes it possible to study the problem of running safety of vehicles on oscillatory bridge deck, which is an importent part in vehicle-bridge dynamic response.——The track deflection on bridge deck due to vibration of the superstructure is defined as second order irregularity of the track, thereby the interaction between vehicle and bridge is derived.——The original irregularities of the track are generated by the method of second order digital filter. ——Based on the vehicle-bridge interaction model, a new decoupling iteration method for solving dynamic equation has been developed. This method is so efficient in saving computer time that the simulation calculation for a whole train crossing a long-span bridge becomes possible on either a mini-computer or a micro-computer.With this method, the dynamic characteristics and interaction of system at different vehicle speeds and different irregularitis are studied. The difference between the dynamic response due to a locomotive and that due to a train formed by a tandem of vehicles and the effect of second order irregularities upon the vehicle system are also investigated.