连杆的标识对其强度影响研究

某型号发动机连杆在进行样品循环载荷疲劳试验时,在连杆杆身中部产品标识位置处发生断裂。对实验样品进行材料和制造工艺检查,发现无缺陷。运用三维建模软件构建三维实体模型,采用有限元方法进行分析,发现与连杆样件试验标识同样位置处发生了应力集中。在此基础上,研究了标识文字间距、相对杆身表面高度、标识位置三个方案对杆身应力的影响,结果表明:适当增加标识文字之间的间距能降低应力;与凸出标识相比,凹陷的标识可大幅度降低应力;标识位置对应力影响最明显,当标识从杆身中部移到连杆盖外侧,杆身应力集中消失。

INFLUENCE STUDY ON THE LOGO OF AN ENGINE CONNECTING ROD TO ITS FATIGUE STRENGTH

The connecting rod breaked in the logo position at the middle of the connecting rod body,when it was subjected to cyclin load fatigue experiment.The material and manufacturing process of the experimental samples were checked and there was no defect.The three-dimension solid model of the experimental connecting rod was built by 3-D modeling software,and the stress concentration had occurred at the same location logo with the experimental sample connecting rod by using finite element method.Then three schemes were designed and the influence on the distance between the logo words,the height of logo to connecting rod body surface and the positing of the logo to stress were analysis,the results showed that: the stress was reduced by appropriately increasing the spacing between logo words.The depressing logo could greatly reduce the stress comparing with the protruding logo.The positon of the logo had the most influence to the stress,and the stress concentration of the connecting rod disappeared when the logo moved from middle of the connecting rod to the outside of the connecting rod cap.