汽车发动机张紧器摆臂断裂失效分析

Fracture Failure Analysis of Tensioner Swing-arm of Automobile Engine

汽车发动机张紧器摆臂进行台架耐久试验时发生断裂失效。通过宏观观察、断口形貌、化学成分、金相组织及硬度等测试方法分析了张紧器摆臂的断裂失效原因。结果表明:张紧器摆臂断裂起始源区存在疏松缺陷,减小了有效承载面积,在外界交变载荷的作用下,疏松缺陷区域产生应力集中,最终导致张紧器摆臂发生断裂失效。

The fracture failure occurred in the tensioner swing-arm of the automobile engine during the endurance test.The fracture failure reasons of the tensioner swing-arm were analyzed by a variety of methods including macroscopic inspection,fracture surface morphology analysis,chemical analysis,metallographic structure observation and hardness test.The results show that the effective bearing area was reduced by the porosity defects in the source area of the tensioner swing-arm fracture.The additional stress concentration was caused in the porosity defect area with the action of external alternating load,and it ultimately led to fracture failure of the tensioner swing-arm.