柴油机连杆疲劳断裂原因分析

Analysis of Fatigue Fracture for Diesel Engine Connecting Rod

针对某柴油机连杆在疲劳试验中断裂失效,进行了断口分析、应力测试及疲劳强度评估分析。结果表明,该连杆的设计结构强度能够满足使用安全性要求,而螺栓孔螺纹加工质量差,造成局部残余应力和形状应力集中,较大程度上降低了该区域结构的疲劳强度,致使连杆在该部位断裂失效。

For the fracture failure of diesel engine connecting rod in the fatigue test, the fracture analysis, stress test and fa- tigue strength evaluation were carried out. The result shows that the designed structure strength can meet the reliability requirement. However, the residual stress and shape stress concentration caused by the worse machining of screw thread for bolt hole decreases the fatigue strength of fracture largely and finally leads to the fracture failure.