基于热-结构耦合的机车整体式车轮疲劳强度分析

Analysis on fatigue strength of locomotive integrated wheel based on thermal-structure coupling

车辆紧急作用下,复杂机械和热载荷会造成车轮结构破坏失效,基于热-结构耦合理论及采用有限元数值仿真分析方法,分析其对整体式车轮结构的机械强度和疲劳强度的影响,并分析对比纯机械载荷和热-结构耦合载荷两种作用下对车轮结构强度的影响,采用单轴及多轴疲劳准则进行疲劳强度评估。结果表明:紧急制动20 s时,踏面温度达到最大151.8℃;制动热载荷是引起踏面及辐板等效应力增大的主要因素,热-结构耦合载荷比纯机械载荷辐板处产生的最大等效应力超出40%左右;多轴Dang_Van疲劳准则更适合应用于车轮辐板的评定,制动热负荷会造成局部结构疲劳强度波动较大,引起车轮的突然破坏。

The complex mechanical and thermal loads will cause the failure of the wheel structure during the vehicle emergency. This paper analyzes the mechanical strength and fatigue strength of the whole wheel structure, based on thermal-structure coupling theory and finite element numerical simulation analysis method. And the influence of two kinds of mechanical load and thermal-structure coupling on the structure strength of the wheel is analyzed and compared, fatigue strength evaluation using uniaxial and multi-axis fatigue criterion. The results show that the maximum temperature reached 151.8 ℃ at 20 s when emergency braking, and the main factor of the equivalent stress of the tread and the wheel plate is the brake thermal load, meanwhile, the maximum equivalent stress of the thermal-structural coupled load is more than 40% of the stress generated by the radiation of the pure mechanical load. Multi-axis Dang_Van fatigue criterion is more suitable for the evaluation of wheel plate, the brake thermal load can lead the local structural fatigue strength to fluctuate, which causes the sudden failure of the wheel.