基于数值仿真的全表面轮毂弯曲疲劳试验及疲劳寿命分析

目的 预测钢制全表面轮毂易产生疲劳破坏的危险区域，并分析其弯曲疲劳寿命。方法 针对全表面轮毂的弯曲疲劳试验工况，建立有限元分析模型，综合考虑螺栓拧紧方式、螺栓预紧力以及材料非线性特征的影响，通过在加载轴末端建立局部坐标系，实现载荷的分解，并最终实现弯矩的动态加载。在此基础上，进行轮毂的受力分析，然后构造适用于轮毂的应力寿命曲线，并使用名义应力法进行疲劳寿命预测。结果 动态弯矩的加载方向变化会显著影响轮辐表面的应力分布特点，螺栓预紧力施加后，螺栓孔附近区域的应力显著增大，在计算中应考虑其影响。在获得各节点载荷历程后，以高应力幅和平均应力为标准，筛选出了轮毂的危险节点。结论 基于数值仿真的本型全表面轮毂弯曲疲劳试验，危险节点位置均位于轮辐通风孔的内圆角附近区域，可有针对性地对该区域进行相应的优化设计，以进一步提高轮毂的弯曲疲劳寿命。分析得到当前轮辋弯曲疲劳寿命约7.6万次，符合国家标准的要求。

Bending Fatigue Test and Fatigue Life Analysis of Full-surface Hub Based on Numerical Simulation

The work aims to predict the dangerous areas prone to fatigue damage and analyze the bending fatigue life of steel full-surface hubs. A finite element analysis model was established for the bending fatigue test condition of the full-surface hub. The method of bolt tightening, the impact of bolt preload on the hub, and the nonlinear characteristics of the material were taken into consideration comprehensively. The load was decomposed by establishing a local coordinate system at the end of the loading shaft, and the dynamic loading of the bending moment was finally realized. On this basis, the stress of the hub was analyzed, the stress life curve applicable to the hub was constructed, and the nominal stress method was used to predict the fatigue life. The change of the loading direction of the dynamic bending moment would significantly affect the stress distribution characteristics of the spoke surface. After the bolt preload was applied, the stress in the area near the bolt hole was significantly increased. Its influence should be considered in the calculation. After the load history of each node was obtained, the dangerous nodes of the hub were selected based on the high stress amplitude and average stress. The dangerous node positions in the bending fatigue test of this type of full-surface hub based on numerical simulation are all located near the inner fillet of the spoke ventilation hole. The corresponding optimization design can be carried out in this area to further improve the bending fatigue life of the hub. It can be analyzed that the current bending fatigue life of the wheel rim is about 76 000 times, which meets the requirements of national standards.