Abstract: In order to predict the fatigue life of the weld of the sub-frame structure, the fatigue S-N curve of the weld was determined through the bench fatigue test of the fillet welding and lap welding. Then the virtual prototype technology is used to obtain the relative damage ratio between the wheel center load and the original road spectrum load to ensure the accuracy of the multi-body dynamics model. Through the finite element weld fatigue simulation analysis, the location where the fatigue life of the sub-frame weld is the smallest is obtained. Finally, the fatigue test of the vehicle's twenty-four channel bench was carried out. The fatigue life times of the bench and the location of the cracks were consistent with the results of the simulation analysis, which verified the reliability of the weld fatigue S-N curve and the prediction results of the simulation analysis.

Key words: Sub-frame, Weld fatigue, Welded joint, Finite element analysis, Bench test

摘要： 为了预测副车架结构的焊缝疲劳寿命,通过角焊和搭接焊两种焊接接头的台架疲劳试验,确定焊缝疲劳S-N曲线。然后利用虚拟样机技术获得轮心载荷跟路谱载荷的相对损伤比值,保证多体动力学模型的精度。通过有限元焊缝疲劳仿真分析,得到了副车架焊缝疲劳最小寿命发生的位置。最后进行整车二十四通道台架疲劳试验验证,台架疲劳寿命次数和开裂的位置跟仿真分析的结果一致,验证了焊缝疲劳S-N曲线和仿真分析预测结果的可靠性。

关键词: 副车架, 焊缝疲劳, 焊接接头, 有限元分析, 台架试验