基于有限元仿真车轮多轴疲劳强度分析

基于UIC510-3规程和热负荷试验，确定了车轮疲劳强度分析的计算载荷工况，采用有限元方法数值模拟了运行状态下车轮的应力变化规律，进行了车轮疲劳强度评定．采用最大主应力方法将多轴应力状态转化为单轴应力，通过Haigh—Goodman疲劳极限方程，得出机械载荷下车轮辐板孔的疲劳强度满足要求；采用Goodman方程，将制动热负荷产生的零．拉脉动循环转化为对称循环，根据辐板材料的S-Ⅳ曲线评价，得出单纯制动热负荷下辐板孔满足疲劳强度要求；提出制动热应力与机械波动应力的叠加方法，采用Miner法则预测机械载荷与制动热负荷组合作用下辐板孔裂纹的形成寿命．由不同载荷下车轮疲劳强度的评价结果，判断出导致辐板孔边裂纹形成的载荷因素是机械载荷与坡道制动的综合作用．

Multi-Axial Fatigue Strength Analysis of Wheel Based on FEA

Based on the UIC510-3 and the thermal load test, the load conditions for analyzing the fatigue strength of the wheel have been determined. The radial stresses under the operation conditions were analyzed by using finite element method and the fatigue strength of the wheel was evaluated. The multiaxial stress was converted into the uniaxial stress with the maximum principal stress method, and the fatigue strength under mechanical load was evaluated. It can be concluded that the fatigue strength can satisfy the requirement with the Haigh-Goodman fatigue limit equation. After converting the zerotensile stress cycle into symmetrical cycle with Goodman equation, the fatigue strength under braking thermal load was evaluated to meet the strength requirement by using the S-N curve of plate material.The stress superimposing method was put forward for solving the stress superimposition under mechanical and thermal loads. The crack life was predicted under integrated effect of the mechanical stress and thermal stress. This fatigue strength evaluating results above showed that the integrated effort of the mechanical load and the grade braking load was the load factor of the crack.