考虑热力耦合的轨道车辆车轮建模与仿真

Modeling and simulation of railway vehicle wheel considering thermo-mechanical coupling

以城市轨道车辆车轮为研究对象,建立了S型辐板轨道车辆车轮模型,利用有限元方法研究了不同磨耗情况下车轮结构应力和热应力的变化特点,分析了结构场和温度场的耦合作用对车轮应力特性的影响,获得了热力耦合作用下的车轮结构应力和热应力的耦合规律。仿真结果表明：随着车轮踏面的磨耗,其结构应力、热应力与耦合应力均呈非线性变化,在车轮直径为800～840mm的磨损区间,耦合应力较稳定,当磨损到直径小于800mm之后,其耦合应力增长较快,特别是磨耗到770mm时,耦合应力骤升,磨耗到限时耦合应力达到179.5 MPa;车轮的耦合应力是复杂的三维空间力系的叠加,在耦合应力分布上,车轮辐板处耦合应力最大点位置发生漂移现象,制动结束时的车轮辐板处耦合应力最大,大于结构应力最大值与热应力最大值,因此,耦合应力在车轮应力中占主导作用,在车轮的结构设计时,建议考虑结构应力和热应力的耦合作用,把耦合应力作为车轮疲劳强度的评价指标。

Urban railway vehicle wheel was taken as research object, and an S-plate wheel model was established. The features of structural stress and thermal stress of wheel under different abrasions were investigated respectively by using FEM, the effects of thermo-mechanical coupling in the structure field and the thermal field on the stress characteristic of wheel were analysed, and the coupling rules of structural stress and thermal stress were obtained by considering thermomechanical coupling. Simulation result shows that the structural stress, the thermal stress and the coupling stress are all nonlinear with the development of tread abrasion of wheel. The coupling stress is stable when the wheel diameter ranges from 840 mm to 800 mm. When the diameter is less than 800 mm, the coupling stress grows faster, especially, when the diameter is 770 mm, the coupling stress rises rapidly. The coupling stress reaches 179.5 MPa under the abrasion-limit working condition. The coupling stress of wheel is produced by the superposition of complex three dimensional force system. For the coupling stress distribution, the phenomenon of drift exists at the position of the maximum coupling stress of wheel plate. The coupling stress of wheel plate becomes maximum at the brake end time, and is greater than both the maximum structural stress and the maximum thermal stress. Therefore, the coupling stress plays a leading role in the wheel stresses. For the structure design of wheel, it is recommended to consider the coupling role between the structural stress and the thermal stress, and to think the coupling stress as the evaluation index of wheel fatigue strength. 3 tabs, 23 figs, 26 refs.