发动机排气门第二热点疲劳寿命预测方法的研究  

Research of Fatigue Life Prediction Method of the 2nd Hot Point for Engine Exhaust Valve

作　　者：杨艳学[1] 刘佐民[1] 董兵[2] 曲文强[2] 

机构地区：[1]武汉理工大学机电工程学院,武汉430070 [2]济南沃德汽车零部件有限公司,济南250022

出　　处：《机械设计与制造》2012年第8期170-172,共3页Machinery Design & Manufacture

基　　金：国家发改委项目资助(2004-024-28)

摘　　要：基于ANSYS建立了发动机气门、气门座与导管组件接触模型,并以此分析了排气门异常工况下的应力状态及其S-N关系曲线,计算出与发动机气缸内压力相对应的排气门第二热点处载荷谱及其累积疲劳损伤率。研究表明:排气门第二热点处存在高弯曲应力,其峰值分别发生在燃烧冲击及落座瞬间;但燃烧冲击时对疲劳损伤率的贡献远高于气门落座时。研究还表明:排气门正常工况下为无限疲劳寿命,影响其早期疲劳失效的主要因素是异常工况—气门往复运动偏摆角;论文基于实例讨论了发动机工作参数与排气门疲劳寿命之间的关系规律。A model to analyze the fatigue life of the 2nd hot point of engine exhaust valve has been developed based on ANSYS and used to discuss the stress state and the s-n curve of exhaust valve at abnormal condition,and to calculate the loading spectrum of the 2nd hot point corresponding with the pressure in the engine cylinder as well the exhaust accumulative total fatigue damage rate.Results shows that： there are high bending stress at the 2nd hot point of engine exhaust valve,and their peak values are respectively happened at combustion impact and the closing impact cases,but the effect of the stress at combustion case on fatigue damage rate is higher than that at closing case.Research also shows that：the fatigue life of the 2nd hot point of engine exhaust valve under normal working condition is infinite,but the abnormal condition greatly affects its fatigue life.The relationship between engine working parameters and the exhaust fatigue life also be discussed in this paper based on some examples.

关 键 词：发动机排气门 有限元 应力谱 疲劳寿命 

分 类 号：TH16[机械工程—机械制造及自动化] TK422[动力工程及工程热物理—动力机械及工程]