焊接残余应力对桥壳疲劳寿命的影响研究

桥壳作为驱动桥的核心零部件，其疲劳寿命对驱动桥乃至整车安全性有决定性的影响，对于制造过程中使用焊接工艺的桥壳，焊接残余应力的影响不容忽略。以某商用车驱动桥桥壳为研究对象，在获得其焊接残余应力分布的基础上，分析焊接残余应力对桥壳在静态载荷和动态循环载荷工况下应力应变响应的影响。使用应变-寿命分析方法对桥壳在弯曲疲劳试验工况下的寿命进行预测，并与台架试验结果进行对比，结果表明考虑焊接残余应力时，疲劳寿命次数和破坏位置的预测结果与试验结果吻合较好，验证桥壳疲劳寿命预测模型的准确性。与不考虑焊接残余应力的模型相比，焊接残余应力导致桥壳疲劳寿命次数降低，且失效位置不同，说明了疲劳寿命预测时考虑焊接残余应力的必要性。本文方法可推广应用于含有焊接残余应力的结构疲劳寿命预测，为结构优化设计提供指导。

Fatigue Life Prediction and Experiment of an Axle Housing Considering Welding Residual Stresses

As the core component of the driving axle, the fatigue life of the axle housing has a great influence on the safety of the drive axle and the whole vehicle. For the welded axle housing, the effect of the welding residual stress should be considered. The fatigue life prediction model of a commercial vehicle axle housing considering welding residual stress via finite element method is established in this paper, the stress and strain response of the axle housing under the bending fatigue test condition are obtained and the strain-life method is applied to predict the fatigue life of the axle housing. The simulation results are compared with the dynamic strain and fatigue life test results of the bending fatigue test, which verifies the accuracy of the fatigue life prediction model in both the fatigue life and the failure location. Compared with the model without considering the welding residual stress, the fatigue life of the axle housing is reduced due to the welding residual stress, and the failure location is different, which indicates the necessity of considering the welding residual stress in the fatigue life prediction. The method presented in this paper could be applied to the fatigue life prediction of structures with welding residual stress, which could provide guidance for structural optimization design.