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1、天津大學(xué)碩士學(xué)位論文KK型管節(jié)點(diǎn)應(yīng)力集中系數(shù)研究姓名:付艷霞申請(qǐng)學(xué)位級(jí)別:碩士專(zhuān)業(yè):船舶與海洋結(jié)構(gòu)物設(shè)計(jì)制造指導(dǎo)教師:于國(guó)友20070101中文摘要在設(shè)計(jì)階段,管節(jié)點(diǎn)最大應(yīng)力通常通過(guò)S-N方法來(lái)評(píng)估海洋平臺(tái)焊接管節(jié)點(diǎn)疲勞壽命。所以應(yīng)力集中系數(shù)的正確確定對(duì)平臺(tái)結(jié)構(gòu)的安全性至關(guān)重要?,F(xiàn)有經(jīng)驗(yàn)公式如Kuang公式、NORSOK公式僅適用于簡(jiǎn)單管節(jié)點(diǎn)如K、X、Y、TX等形式,對(duì)空間的復(fù)雜管節(jié)點(diǎn)的應(yīng)力集中系數(shù)的計(jì)算未涉及。通常把復(fù)雜的管節(jié)點(diǎn)的應(yīng)力集中系數(shù)看成是簡(jiǎn)單管節(jié)點(diǎn)應(yīng)力集中系數(shù)的疊加。對(duì)本文研究的KK型管節(jié)點(diǎn)來(lái)說(shuō),與相同尺寸的K型管節(jié)點(diǎn),應(yīng)力集中系數(shù)通常要大出許多,所以傳統(tǒng)的計(jì)算簡(jiǎn)單管節(jié)點(diǎn)
2、應(yīng)力集中系數(shù)的經(jīng)驗(yàn)公式并不適合計(jì)算復(fù)雜管節(jié)點(diǎn)應(yīng)力集中系數(shù),因此建立復(fù)雜管節(jié)點(diǎn)應(yīng)力集中系數(shù)參數(shù)方程是非常有必要的。本文在以前對(duì)簡(jiǎn)單管節(jié)點(diǎn)研究基礎(chǔ)上,運(yùn)用軟件ANSYS,用薄壁殼單元分析建立上千個(gè)用在平臺(tái)結(jié)構(gòu)中的承受軸向力、平面內(nèi)彎矩和平面外彎矩三種荷載作用的KK型節(jié)點(diǎn),得出的結(jié)果數(shù)據(jù),通過(guò)不定尺寸的節(jié)點(diǎn)幾何比例反,),.f,∥.f和臼建立函數(shù)通過(guò)回歸分析得出一系列新的參數(shù)方程。這些參數(shù)方程可以用來(lái)計(jì)算得出KK型復(fù)雜管節(jié)點(diǎn)撐桿和弦桿處圍繞交界處的最大應(yīng)力。本文并進(jìn)一步,通過(guò)圖、表形式分別分析a,),.孝,盧,f和0各個(gè)參數(shù)對(duì)KK型節(jié)點(diǎn)在三種荷載作用下?lián)螚U和弦桿SCF的影響,各個(gè)參數(shù)對(duì)對(duì)有
3、限元計(jì)算的KK型節(jié)點(diǎn)與對(duì)相同尺寸的K型節(jié)點(diǎn)經(jīng)驗(yàn)公式所得撐、弦桿的SCF差距的影響。本文對(duì)復(fù)雜KK型管節(jié)點(diǎn)應(yīng)力集中系數(shù)參數(shù)方程的研究對(duì)以后研究其它復(fù)雜節(jié)點(diǎn)SCF和管節(jié)點(diǎn)設(shè)計(jì)有一定參考價(jià)值。關(guān)鍵詞:管節(jié)點(diǎn),應(yīng)力集中系數(shù),有限元,參數(shù)方程ABSTRACTThemaximumstressisveryimportantinestimatingthefatiguelifeofoffshorex-jointsbyanS-Napproach.Therefore,stressconcentrationfactor(SCF)iscrucialforthesafetyofoffshoreplatforms
4、.TheexistingempiricalformulassuchasKuangformulaandNORSOKformulaaresuitableonlytosimpletubularjointsincludingK、X、YandTXetcjoints.SCFforcomplexspatialtubularjointshasnotbeenreferredintheexistingempiricalformulas.Instead,SCFforcomplextubularjointsisusuallyconsideredbythemethodforsimpletubularjoint
5、s.ComparingtotheresultsforsimpleKjointwiththesamedimensions,it’SshowninthispaperthatSCFforKKtubularjointsisfrequentlyhigher,TheexistingempiricalSCFformulasforsimpletubularjointsarenotsuitableforcomplextubularjoints,therefore,itisessentialtOestablishSCFparametricequationsforcomplexKK-joints.Base
6、donformerresearchonsimpletubularioints,thin.shellelementanalyseshavebeenconductedforthousandsofKKjointfrequentlyusedinoffshorestructures.TheseKKjointsaresubjectedtothreekindsofloadings,includingaxialload,in-planemomentandout-planemoment.Byuseofregressionanalysis,theaboveresultsarethenusedtOderi
7、veanewsetofparametricequations。intermsofseveralnon-dimensionalgeometricratios0【,丫,毛,p,Tand0.TheseparametricequationscouldbeuseddirectlytocalculatethemaximumstressaroundtheinterfacebetweenbraceandchordofKKtubularjoints.Furtherinthe