Abstract: Aiming at the problem of cracking near the weld of air conditioning pipeline of a certain passenger car during the road test, random vibration finite element analysis is carried out on the basis of prestressed modal analysis, and it is found that the weak part of the pipeline is consistent with the road test fracture part. The weld size of the pipeline and joint is optimized by increasing the fillet size of the weld, and random vibration finite element analysis is carried out again. The results show that the maximum stress in the three vibration directions of the fracture weld is reduced by 9.8%, 29.5% and 45.2% respectively, and the maximum stress is reduced from 112.1 MPa to 86.1 MPa, which is lower than the yield limit of the material and meets the strength requirements. The study provides a reference for finite element analysis of random vibration of automotive air conditioning pipelines and strength optimization of welded structures.

Key words: Automobile air conditioning pipeline; Random vibration; Strength

摘要： 针对某款乘用车路试期间空调管路焊缝附近发生断裂的问题，在预应力模态分析的基 础上对其进行了随机振动有限元分析，发现其强度薄弱部位与路试断裂部位一致，采用增大 焊缝圆角尺寸的方法对管路与接头处焊缝尺寸进行优化，再次对其进行随机振动有限元分析。 结果表明，断裂焊缝处三个振动方向的最大应力分别降低了 9.8%、29.5%、45.2%，最大应力 由 112.1 MPa 降低至 86.1 MPa，低于其材料屈服极限，满足强度要求。研究为汽车空调管路 随机振动有限元分析与焊接结构强度优化提供参考依据。

关键词: 汽车空调管路；随机振动；强度