某柴油机连杆结构改进与评估

针对某柴油机连杆在疲劳强度验证试验过程中发生的螺纹底孔位置断裂失效故障，进行了连杆试验载荷、材料性能、宏观断口及结构应力分析，指出了螺栓孔底部过渡尖锐造成应力集中是导致连杆在循环载荷作用下疲劳断裂的主要原因，据此提出连杆螺栓孔结构改进设计方案，通过结构应力仿真、疲劳强度仿真分析以及疲劳试验验证，结果均表明结构改进合理有效。

Structure Modification and Evaluation of Diesel Engine Connecting Rod

For the fracture failure at the bottom of screw thread hole during the fatigue test of connecting rod of a diesel en‐gine ,the test load ,material performance ,macroscopic fracture and structure stress were analyzed .It was pointed out that the concentrated stress caused by the sharp transition at the bottom of screw thread hole was the main reason for fatigue fracture under cyclic loading .Then the improved scheme of connecting rod screw thread hole was put forward ,and the simulation of structural stress and fatigue intensity and the verification of fatigue test were carried out .The results show that the improved structure is feasible and effective .