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1、橋梁建設(shè)2015年第45卷第5期(總第234期)BridgeConstruction,Vo1.45,No.5。2015(TotallyNo.234)77文章編號(hào):1003—4722(2015)05—0077—06面外變形下鋼橋的疲勞貫通裂紋擴(kuò)展行為研究鞠曉臣,趙欣欣,劉曉光(中國(guó)鐵道科學(xué)研究院,北京100081)摘要:為了解鋼橋的疲勞貫通裂紋在面外變形作用下的發(fā)展規(guī)律,對(duì)其擴(kuò)展行為進(jìn)行研究。制作雙軸對(duì)稱長(zhǎng)方形鋼板試件進(jìn)行面外變形疲勞試驗(yàn),選取5種應(yīng)力比(0、一0.25、一0.5、一0.75、一1)進(jìn)行加栽,得到應(yīng)力比為一1時(shí)的裂紋前沿為V形,其他應(yīng)力比時(shí)裂紋前沿基本以1/4橢圓狀為
2、主。將得到的裂紋前沿引入到數(shù)值模型中,對(duì)應(yīng)力比為一1與0時(shí)的裂紋擴(kuò)展情況進(jìn)行數(shù)值分析,通過(guò)J能量積分法計(jì)算得到沿不同裂紋前沿的應(yīng)力強(qiáng)度因子分布。結(jié)合既有應(yīng)力強(qiáng)度因子計(jì)算公式和數(shù)值計(jì)算結(jié)果,提出基于實(shí)際裂紋前沿的面外變形作用下的疲勞裂紋應(yīng)力強(qiáng)度因子計(jì)算公式修正系數(shù),針對(duì)不同的裂紋長(zhǎng)度建議在0.43~0.54取值。關(guān)鍵詞:鋼橋;貫通疲勞裂紋;裂紋前沿形狀;應(yīng)力強(qiáng)度因子;面外變形;應(yīng)力比;數(shù)值分析中圖分類(lèi)號(hào):U448.36;U441.4文獻(xiàn)標(biāo)志碼:AStudyofPropagationBehaviorofThrough—ThicknessFatigueCracksofSteelBridg
3、eUnderOut—Of-PlaneDeformation.,【,Xiao—chen,ZHAOXin-xin,LIUXiao-guang(ChinaAcademyofRailwaySciences,Beijing100081,China)Abstract:Tounderstandthepropagationlawsofthethrough—thicknessfatiguecracksofsteelbridgeundertheout—of-planedeformation,thepropagationbehaviorofthefatiguecrackswasstudied.Anobl
4、ongsteelplatespecimenofdouble—axissymmetrywasfabricatedandthefatiguetestsforthespecimenundertheout—of—planedeformationweremade.Thespecimenwasloadedby5selectedstressratios(0,一0.25,一0.5,~0.75and一1)andthecrackfrontobtainedatthestressratio?!?wastheVshapewhilethecrackfrontsobtainedatotherstressrat
5、ioswerebasical_—lYmainlythe1/4ellipticalshapes.Theobtainedcrackfrontswereintroducedintothenumericalmodelandthepropagationofthecracksatthestressratios一1and0wasnumericallyanalyzed.ThedistributionofthestressintensityfactorsalongthedifferentcrackfrontswasobtainedbythecalculationoftheJ-integralmeth
6、od.Withreferencetotheexistingformulaeforthestressintensityfactorsandtheresuitsofthenumericalcalculation。thecorrectioncoefficientsfortheformulaofthefatiguecrackstressintensityfactorsbasedontheactualcrackfrontsundertheout——of——planede’—formationweregivenandinaccordancewiththedifferentcracklength
7、,itwasproposedthatthevaluesofthecorrectioncoefficientsshouldbeselectedintherangeof0.43~0.54.Keywords:steelbridge;through—thicknessfatiguecrack;crackfrontshape;stressintensityfactor;out—of-planedeformation;stressratio;numericalanalysis1引