汽车发动机右悬置支架及螺栓断裂失效分析

Fracture Failure Analysis of Engine Right Mounting Brackets and Screw Bolts

汽车发动机右悬置支架及螺栓在试验场进行综合耐久试验时发生断裂失效。通过宏观检查、断口形貌、化学成分、金相组织及硬度等测试方法,分析了悬置支架和螺栓的断裂失效模式,并采用数值模拟方法进一步分析了断裂失效的原因。结果表明:悬置支架在交变载荷作用下,接触面之间发生相对滑移,导致连接螺栓发生疲劳断裂,最终导致悬置支架的断裂。

The fracture failure occurred in engine right mounting bracket and screw bolt of the automobile during the comprehensive endurance test at the proving ground.The fracture failure mode of engine mounting bracket and screw bolt was analyzed by a variety of methods including macroscopic inspection,fracture surface morphology analysis,chemical analysis,microstructure observation and hardness testing.The numerical simulation was also performed to analyze the reason of fracture failure.The results show that the fatigue fracture of the connecting bolt was caused by relative slip between the contact surfaces of the mounting bracket under the alternating load,which ultimately leads to the fracture of the mounting bracket.