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大小:1.86 MB
页数:6页
时间:2019-02-27
《基于损伤_断裂力学理论的起重机疲劳寿命估算方法_范小宁》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、第21卷第9期中国安全科学学报Vol.21No.92011年9月ChinaSafetyScienceJournalSep.2011基于损伤-断裂力学理论的起重机*疲劳寿命估算方法范小宁副教授徐格宁教授杨瑞刚副教授(太原科技大学机械工程学院,山西太原030024)学科分类与代码:6203030(安全设备工程)中图分类号:X952;TH215文献标志码:A基金项目:山西省自然科学基金资助(2010011031-5)。资助项目:国家科技支撑计划资助项目(2006BAK02B04-01-02)。【摘要】鉴于断裂力学无法估算裂纹形成寿命及难以确定其初始裂纹尺寸,提出将损伤力学与断裂力学相结合共
2、同估算起重机疲劳寿命的思想。针对Paris公式应用的局限性,提出将裂纹扩展率与应力强度因子幅对数线性阶段的某一裂纹尺寸作为裂纹形成寿命和裂纹扩展寿命的分界点。用损伤力学估算疲劳裂纹的形成寿命,用断裂力学估算疲劳裂纹的扩展寿命,两者寿命之和构成起重机的疲劳全寿命。这样做既能避免断裂力学寿命估算中确定初始裂纹尺寸的混乱现象;又能确保Paris公式应用在裂纹扩展率与应力强度因子幅的对数线性阶段。试验验证结果表明,估算疲劳全寿命和试验寿命基本吻合。【关键词】损伤力学;断裂力学;起重机焊接箱形梁;疲劳总寿命;裂纹形成寿命;裂纹扩展寿命;分界点FatigueLifePredictionofCra
3、neBasedonDamage-fractureMechanicsFANXiao-ningXUGe-ningYANGRui-gang(CollegeofMechanicalEngineering,TaiyuanUniversityofScienceandTechnology,TaiyuanShanxi030024,China)Abstract:Inviewofthefactthatthecrackformationlifecouldnotbepredictedthroughfractureme-chanicsandthattheinitialcracksizeisdifficultt
4、odetermine,theideathatthefatiguelifeofcraneisas-sessedbythecombinationofdamagemechanicsandfracturemechanicsisproposed.Consideringthelimi-tationofParisformula,acertaincracksize,whichbelongstothelog-linearphasebetweencrackgrowthrateandstressintensityfactorrange,ispresentedasthedividingpointbetwee
5、nthecrackformationlifeandthecrackpropagationlife.Thus,ontheonehandtheconfusionphenomenaofdeterminingtheinitialcracksizeareavoidedinthefracturemechanicsmethodofestimationoffatiguelife;ontheotherhanditiscertainthattheParisformulaisusedinthelog-linerphasebetweencrackgrowthrateandstressintensityfac
6、torrange.Thecrackformationlifeandthecrackpropagationlifeareestimatedrespectivelybythedam-agemechanicsandthefracturemechanics.Thesetwolivescomposethefatiguetotallifeofcrane.Experi-mentalresultindicatesthatthefatiguetotallifebasicallytallieswiththeexperimentallife.Keywords:damagemechanics;fractur
7、emechanics;weldedboxgirdersofcrane;fatiguetotallife;crackformationlife;crackpropagationlife;dividingpoint*文章编号:1003-3033(2011)09-0058-06;收稿日期:2011-07-13;修稿日期:2011-08-29第9期范小宁等:基于损伤-断裂力学理论的起重机疲劳寿命估算方法·59·0引言1起重机焊接箱形梁疲劳裂纹形成寿命估算的损伤力学
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