重型卡车排气制动阀支架失效有限元分析

Vibration Characteristics and Failure Analysis of a Heavy-Duty Truck Exhaust Brake Bracket Using Finite Element Technique

针对某重型卡车排气制动阀支架在固定螺栓孔周围或是菱形垫片周围发生开裂问题,对失效件进行了宏观观察、断口形貌观察和零件材料理化检验,并运用有限元分析技术对失效件的受载情况进行了模拟分析;考虑到零件的结构特点对零件的振动特性进行了分析。综合分析认为:排气制动阀支架材料与设计要求一致;排气制动阀支架主要承受气缸工作载荷和机械振动载荷的弯扭复合作用,且菱形垫片没有起到有效的加强作用,导致发生疲劳断裂;机械振动对导致零件失效起的作用更大一些,进行零件改进时应关注零件结构的振动稳定性。

The exhaust brake bracket of a heavy-duty truck cracked around the fixed bolt holes or cracked near the diamond- shaped gasket region. To find the causes of the crack failure, Failure parts macroscopic observation, the fracture morphology and the physical and chemical testing of the part material were performed. In addition, using finite element analysis techniques, a simulation analysis of the part the loading condition was carried out. Meanwhile, taking the structural features of the part into account, the vibration characteristics of the part was analyzed. And based on all the results acquired, the following conclusions can be drawn. First, the material of the exhaust brake bracket fully meets the design requirements. Second, the part withstands a bending and torsion load which plays a key role on leading to fatigue fracture, and mechanical vibration played a more important role than cylinder working load. In the end, to improve the part performance, more concerns should be put on the structure vibration stability of the part.