顶推螺栓预紧连接数值模拟及结构参数影响分析.pdf

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1、固体火箭技术第37卷第4期JournalofSolidRocketTechnologyVo1．37No．42014顶推螺栓预紧连接数值模拟及结构参数影响分析①李占山，程可，陆晓峰(南京工业大学机械与动力工程学院，南京211816)摘要：针对大规格螺栓预紧力难以控制、螺纹根部应力集中严重，极易形成裂纹而造成连接失效的现状，顶推螺栓预紧连接方式逐渐被引入高负荷的大型关键设备中。该文利用有限元软件ABAQUS对一顶推螺栓预紧连接进行了三维数值模拟，研究了各连接元件的应力分布并和普通螺栓预紧连接进行了对比，分析了顶推螺栓中心圆直径及其螺距对连接结构应力的影响。结果表明，此预紧连接使主螺栓第1

2、道螺纹根部应力下降超过50％，而螺母整体应力增大，但其螺纹根部应力沿轴向不均匀性降低了30％，极大地改善了应力集中现象；减小顶推螺栓的中心圆直径可降低主螺栓螺纹根部应力，但会导致螺母应力上升，而对顶推螺栓应力没有明显影响；增加顶推螺栓螺距可略降低螺母螺纹根部应力，主螺栓螺纹根部最大应力也有小幅增加，当螺距为1．5mm细牙时，项推螺栓螺纹自身应力最小。关键词：顶推螺栓；预紧连接；螺纹应力；结构参数；数值模拟中图分类号：V431文献标识码：A文章编号：1006—2793(2014)04—0556—07Dol：10．7673／j．issn．10ID6-2793．2014．04．024Num

3、ericalsimulationandstructuralparameteranalysisofpushingboltpreloadconnectionLIZhan—shan，CHENGKe，LUXiao—feng(CollegeofMechanicalandPowerEngineering，NanjingUniversityofTechnology，Nanjing211816，China)Abstract：Aimingatthesituationthatthepreloadoflarge—sizedboltisdificulttocontrolandthestressconcent

4、rationatthebottomofthethreadisserious，whichmaycausecrackandconnectionfailure，thepushingboltpreloadconnectionwasintroducedin—tothelarge—scaleandhigh·loadcriticaldevices．Inthispaper．three—dimensionalnumericalsimulationofapushingboltpreloadcon—nectionwasconductedbymeansoffiniteelementsoftwareABAQU

5、S，thestressdistributionofeachconnectingcomponentwasstud—iedandalsocomparedwiththecommonboltconnection，andtheinfluencesofthepushingboltcirclediameterandpitchonthecon—nectionstructuralstresswereanalyzed．Theresultshowsthatthepre—tighteningconnectionmakesthemaximumstressdecreaseby50％atthebottomofth

6、efirstthreadinmainbolt，andwiththeincreaseofoverallstressoftheroundnut，theinhomogeneityofthreadbottomstressalongtheaxialisreducedby30％，thestressconcentrationisgreatlyimproved；themainbohthreadrootstresswillbereducedbydecreasingtheconcentriccirclediameterofthepushingbolt，butitwillcausenutstressinc

7、rease，whiletheeffectonpushingboltstressisnotsignificant；thenutstresswillbedecreasedslightlywiththeincrementofthepushingboltpitch，themaximumstressatthebottomofmainboltthreadalsoincreaseslightly，whenthepushingboltpitchis1．5mm，thethr