某车型水箱下横梁开裂分析研究

针对某车型可靠性试验时发生车身水箱下横梁异常开裂问题，通过多体动力学分析获得车身悬置点载荷并进行有限元分析，对车身水箱下横梁开裂问题进行分析和验证.结果表明水箱下横梁异常开裂是由于下横梁台阶处有应力集中现象，台阶开裂位置的最大应力值为294.2 MPa，选用材料为HC340LAD+Z，屈服的极限为340 MPa，但因高周疲劳（循环次数较多）依然产生破坏，找到开裂原因，并提出结构优化方案，通过道路试验验证，优化后的结构能够满足设计要求.

Cracking Analysis and Research for Water Tank Lower Beam of A Vehicle

In order to resolve cracking problem appeared in the reliability test for the lower beam of the water tank, the body suspension point load was studied based on multi-body dynamics analysis and finite element analysis to analyze and verify the cracks taken place in the water tank lower beam. The results show that the abnormal cracking of the lower beam of the water tank is due to the stress concentration at the step of the lower beam. The maximum stress in the cracked position of the step is about 294.2 MPa with the material HC340LAD+Z and yield limit 340 MPa. However, when high-cycle running (more cycle times), fatigue damage can still occur. Considering the cause of cracking, a structural optimization program was proposed. Through road test verification, the optimized structure can meet the design requirements.