基于欧拉梁假定的柔性多体动力学车桥耦合振动分析模型

A train-bridge coupling vibration model considering car-body flexibility based on Euler beam hypothesis

基于柔性多体动力学理论建立了能够考虑车体柔性的车辆模型,在模型中,将车体简化为一根长度为车体长度的欧拉梁,利用自由边界欧拉梁的弹性振型代替车辆的弹性振型,此时车体的运动等于车体的刚性运动叠加自由边界欧拉梁弹性振型的广义运动.研究表明:考虑车体柔性时,车体的动力响应增大,且在轨道不平顺及桥梁激励下,车体加速度在某些车速点会产生共振;车体刚度并非越大越好,在一定的速度等级下,车体刚度较大时的车辆动力响应反而更为剧烈;车体柔性对桥梁动力响应、轮轨横向力、脱轨系数和轮对减载率影响很小.

Vehicle model is created based on flexible multibody dynamics, which can consider the influ- ence of flexibility of the car-body. In this model, the car-body is simplified to an Euler beam with the length equal to the length of car-body. The vibrate mode of car-body is simulated as the vibrate mode of Euler beam with free boundary, in this condition, the displacement of the car-body is the superposi- tion of rigid displacement of car-body and generalized displacement of vibrate mode of Euler beam with free boundary. The calculated results show that the dynamic response of car-body will increase and the resonance will appear at certain speeds under the excitation of track irregularity when we consider the influence of flexibility of the car-body. The stiffness of car-body is not the larger the better, under a certain speed a larger stiffness of car-body will induce more violent vibration of vehicle. The dynamic response of bridge, lateral wheel/rail force, derailment factor and off-load factor are hardly affected by the flexibility of the car-body.