基于刚柔耦合的轨道车辆转向架构架疲劳分析

Fatigue Analysis for Bogie Frame Based on Rigid-Flexible Coupling Simulation

对某型地铁车辆转向架构架在运行使用过程中局部区域出现裂纹的问题,首先,基于固定界面模态综合法,通过构架主自由度缩减得到了该型构架柔性体模型,从而建立该型地铁车辆刚柔耦合多体动力学模型;然后,结合一种基于柔性体计算结构动应力的方法,探讨该型构架的动应力响应,得到该型构架的振动特性;最后,采用准静态应力叠加法对构架电机吊座结构进行了疲劳寿命预测。仿真结果与该型构架实际出现疲劳破坏的位置吻合,从而验证了基于刚柔耦合模型对构架进行疲劳分析方法的正确性。结果表明,利用这种方法可以在构架前期开发阶段为其疲劳寿命预测提供理论依据。

Bogie frame is one of the important parts of an urban subway vehicle, but it usually occurs to fatigue crack. Traditional dynamic characteristic analysis for bogie frame is generally based on multi-body dynamics simulation and finite element analysis, this method is suitable for the structural natural frequency away from the external loading frequency, consequently its result has certain limitations. In order to study dynamic response characteristics and fatigue strength of a bogie frame,a rigid-flexible coupled multi-body dynamic model of the bogie frame is established based on the finite element analysis method and the rigid-flexible multi-body dynamics theory. The dynamic stress response of bogie frame is carried out based on rigid-flexible coupling multibody dynamic model of the metro vehicle, from which vibration characteristics of this type of the bogie frame can be obtained. Then, failure mechanism of the bogie frame can be obtained based on fatigue analysis of local fatigue areas of the bogie frame. The stress time histories of its bogie frame necessary for fatigue analysis are calculated with the results of the multi-body dynamic simulation taken as the dynamic load by using the finite element analysis method. The fatigue life of the bogie frame is predicted by using the quasi-static stress superposition method. The calculation results show regions of the bogie frame with excessively large stress amplitude are concentrated on the motor hanger region, gear box hanger region and the connected region between the beam and side beams. The simulation result conforms to the location of actual fatigue bogie damage on this frame, thus verifying the correctness of the method on structure fatigue analysis based on the rigid-flexible coupled model. The shortest lifetime of the motor hanger obtained from the simulation is 1 530 000 km. The error of the result of simulation and the actual data is 10%, which illustrates high credibility and accuracy of the simulation. © 2017, Editorial Department of JVMD. All right reserved.