某柴油机四螺栓连杆失效分析与优化验证

Failure Analysis and Optimized Validation of Certain Diesel Engine Con-rod with Four Bolts

针对某柴油机连杆失效问题,通过失效模式分析,FEA耦合应力分析,连杆螺栓材料检测,连杆螺栓拧紧工艺调查,螺栓预紧力和强度校核等手段,发现使用75(N·m)+60°的拧紧规范超出了螺栓预紧力限值,螺栓过拧紧是导致连杆失效的主因。采取综合改进措施后,整机顺利通过了500 h超速耐久试验,再未发生类似失效问题。

To solve the failure of a certain diesel engine’s con-rod,through using failure mode analysis,FEA coupling stress analysis,con-rod bolt material analysis,con-rod bolt tightening process investigation,and bolt pretightening force and strength check,it was found that the 75（N·m） ＋60° specification was out of the bolt pretightening limitation,and over-torque situation was the main cause of the con-rod failure.After improvement,the whole engine passed the 500 h over speed endurance test,and no such failures occurred again.