某柴油机连杆运行全过程疲劳分析
孙久洋,张洋洋,王厚权,高坤,陈海瑞,宫继儒
潍柴动力股份有限公司,山东 潍坊 261061
摘要:为解决某柴油发动机捣缸故障,通过连杆受力、疲劳试验及有限元仿真分析确定故障原因。分析结果表明:连杆大头垂直于杆身方向受力主要由连杆自身惯性力引起;疲劳试验仅能反映连杆最大拉伸载荷及压缩载荷下的受力情况,不能体现其他时刻连杆受力情况;连杆定位齿形处疲劳安全因数最小,为1.05,确定连杆定位齿形处产生疲劳断裂,导致发动机出现捣缸故障。对连杆加工工艺进行改进,将齿形定位改为胀断定位,解决了定位齿形疲劳安全因数较低的问题,未出现发动机捣缸故障。
关键词:连杆;疲劳试验;疲劳强度分析;疲劳断裂;有限元仿真
Fatigue analysis of the entire process of connecting rod operation for a diesel engine
SUN Jiuyang, ZHANG Yangyang, WANG Houquan, GAO Kun, CHEN Hairui, GONG Jiru
Weichai Power Co., Ltd., Weifang 261061, China
Abstract:In order to solve the cylinder tampering fault of a certain diesel engine, the reason is determined through connecting rod force analysis, fatigue tests, and finite element simulation analysis. The analysis results show that the force on the connecting rod head perpendicular to the rod direction is mainly caused by the inertia force of the connecting rod itself. The fatigue test can only reflect the force situation of the connecting rod under the maximum tensile load and compressive load, and can not reflect the force situation of the connecting rod at other times. The fatigue safety factor at the tooth profile of the connecting rod positioning is the smallest, which is 1.05. It is determined that fatigue fracture occurs at the tooth profile of the connecting rod positioning, leading to cylinder tampering failure in the engine. The machining process of the connecting rod is improved by changing the tooth shape positioning to the expansion and fracture positioning, which solve the problem of low fatigue safety factor of the positioning tooth shape and does not result in engine cylinder tampering failure.
Keywords: connecting rod; fatigue test; fatigue strength analysis; fatigue fracture; finite element simulation