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发动机活塞销孔结构强度分析及改善摘要活塞是发动机中最重要的零部件之一，工作中要承受周期性热负荷和机械负荷冲击，活塞的工作状态直接决定着发动机的使用寿命。高温、高压的工作环境使承载最大机械应力的活塞销孔部位面临着更大的考验。活塞销座部位工作温度在200℃左右，活塞销与活塞销孔之间的磨擦还产生着高温负荷。因此有必要对活塞进行有限元计算分析，弄清活塞及其销孔处的机械应力分布规律，为改进设计提供依据。本文通过PRO/E建立活塞组的1/2实体模型。再运用ANSYS分析软件计算活塞的机械应力与变形，得出活塞销孔内侧应力集中，变形较大。并在此基础上，提出了活塞的结构改进措施，采用了在活塞销孔内嵌入铸铝青铜衬套。针对改进设计方案进行了有限元分析，结果表明该改进方案使得活塞销孔内侧的应力趋向均匀，改善了销孔的应力集中现象，降低了销孔表面应力峰值，达到了预期的效果。关键词:活塞；机械应力；有限元AbstractOneofthemostimportantpartsofanenginedirectlygoverningenduranceisthepiston,whichperiodiclybeartheimpactofheatloadandmechanicalload.Hightemperature,highpressureworkingenvironmentmakethepistonpinholebearingthemaximummechanicalstressloadpositionfaceevengreaterchallenge.Pistonbossworksinthetemperatureofabout200℃,andthefrictionbetweenthepistonpinholeandpistonpinalsoproducesahightemperatureload.Therefore，itisnecessarytodothefiniteelementanalysisforthepiston，clarifydistributionofthermalstressandmechanicalstressofthepistonstoprovideabasisforimprovingthedesign.Thisarticleestablishpistonrangeof1/2solidmodelsbyPRO/E.ThenusingANSYSsoftwaretocalculatemechanicalstressanddeformationofthepiston,weobtainstressconcentrationinsidethepistonpinhole,andwithalargedeformation.Inviewofthis,itproposesmeasuresofimprovingpistonstructuredesignandadoptsthestructureofcastaluminumbronzeembeddedintheholeinthepistonpinbushing.Theresultsshowthattheprogramhasmadethestressinsidethepistonpinholetendtobeeven，improvedstressconcentrationphenomenonofthepinholeandreducedthesurfacestresspeakofthepinholeandachievedthedesiredresults.Keywords:piston；finiteelement；mechanicalstress目录1引言.........................................................................................................................11.1概述........................................................................................................................................................11.2国内外研究现状.................................................................................................................................21.3课题研究的主要内容和方法..........................................................................................................32有限元基础理论及活塞组有限元模型的建立....................................................42.1有限元基础理论及ANSYS简介..................................................................................................42.1.1有限元法概述..........................................................................................................................42.1.2有限元法划分原则.................................................................................................................52.1.3ansys简介.................................................................................................................................92.2活塞组有限元模型的建立.............................................................................................................102.2.1活塞组几何模型的建立......................................................................................................102.2.2结构强度分析的基本概念..................................................................................................142.2.3活塞组的受力模型...............................................................................................................172.2.4活塞组边界条件的确定......................................................................................................212.2.5活塞组有限元模型...............................................................................................................213活塞组应力及变形的研究..................................................................................233.1活塞组在机械载荷下的变形研究...............................................................................................233.2活塞组在机械载荷作用下应力分析...........................................................................................244活塞销孔结构改进后的有限元分析..................................................................274.1衬套的材料及几何模型的确定....................................................................................................274.2活塞组有限元模型的建立.............................................................................................................274.3活塞组的机械载荷及边界条件的确定......................................................................................284.4活塞组机械载荷下变形的分析....................................................................................................284.5活塞组机械载荷下的应力分析....................................................................................................30结论...........................................................................................................................33展望...........................................................................................................................34参考文献.....................................................................................................................35致谢...........................................................................................................................37平顶山工业职业技术学院毕业设计说明书（论文）第1页1引言1.1概述发动机是一种将燃油化学能转变成为机械功的动力机械。这种能量转换是燃油在气缸中与空气充分混合进行燃烧，