文章针对某新能源车后门开闭耐久试验（25000 次循环）中侧围锁扣安装区焊点附近钣金开裂问题，以后半车身为研究对象，采用试验与有限元分析（FEA）结合的方法，分析该区域疲劳应力分布。针对焊点区域疲劳性能劣于一般结构区域的问题，提出 5 种以焊点调整、结构胶添加为核心的改进方案，通过仿真分析评估各方案耐久性能，并对最优方案进行台架试验验证。结果表明：有限元分析识别的危险区域与试验开裂区域一致；最终选定在原始方案基础上增加结构胶的方案，使侧围外板应力降至 124 MPa（低于 DC06 冷轧钢板弹性极限 180 MPa），试验循环次数超 50000 次，满足开闭耐久要求，且兼顾成本与工艺，为同类车身疲劳问题提供参考。

This paper focuses on the problem of sheet metal cracking near the weld points in the side panel lock installation area of a new energy vehicle during the rear door opening and closing durability test (25,000 cycles). The rear half of the vehicle body is taken as the research object, and the fatigue stress distribution in this area is analyzed by combining tests with Finite Element Analysis (FEA). Aiming at the problem that the fatigue performance of the solder joint area is inferior to that of the general structural area, five improvement schemes centered on solder joint adjustment and structural adhesive addition are proposed. The durability performance of each scheme is evaluated through simulation analysis, and the optimal scheme is verified through bench tests. The results show that the hazardous areas identified by the finite element analysis are consistent with the crack areas in the test. The final selected scheme of "adding structural adhesive on the basis of the original scheme" reduced the stress of the side panel to 124MPa (lower than the elastic limit of 180MPa of DC06 cold-rolled steel plate), with over 50,000 test cycles, meeting the requirements of opening and closing durability, while also taking into account cost and process, providing a reference for similar body fatigue problems.