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《預(yù)拉伸控制鋁合金筒體環(huán)焊縫焊接殘余應(yīng)力及變形的數(shù)值模擬》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫(kù)。
1、摘要摘要本文是在鋁合金平板對(duì)接焊縫預(yù)拉伸焊接試驗(yàn)的基礎(chǔ)上，提出預(yù)拉伸對(duì)鋁合金筒體環(huán)焊縫焊接殘余應(yīng)力和殘余變形影響的數(shù)值模擬研究設(shè)想。文中通過(guò)對(duì)有限元分析方法介紹，通過(guò)實(shí)體建模法建立模型，采用表面均勻熱源模型，采用自由網(wǎng)格劃分法劃分網(wǎng)格，在柱狀坐標(biāo)體系下通過(guò)循環(huán)語(yǔ)句實(shí)現(xiàn)熱源移動(dòng)，依靠數(shù)值分析理論處理7075鋁合金熱物理性能參數(shù)材料,對(duì)有無(wú)預(yù)拉伸應(yīng)力條件下鋁合金筒體環(huán)焊縫對(duì)接焊接過(guò)程中焊接區(qū)域溫度場(chǎng)、應(yīng)力應(yīng)變場(chǎng)進(jìn)行了三維實(shí)時(shí)動(dòng)態(tài)模擬分析，探討了筒體焊接過(guò)程中應(yīng)力及變形的變化規(guī)律，和預(yù)拉伸應(yīng)力對(duì)鋁合金筒
2、體的焊接應(yīng)力及變形的影響特征。數(shù)值模擬分析結(jié)果表明，預(yù)拉伸焊接法可以有效控制鋁合金筒體環(huán)焊縫焊接殘余應(yīng)力和殘余變形，預(yù)拉伸應(yīng)力為90%σ0.2時(shí)焊接，其焊后殘余應(yīng)力峰值最小，筒體斷面上縱向殘余應(yīng)力分布曲線平緩，殘余應(yīng)力降低了50%左右；采用預(yù)拉伸焊接法可以有效控制鋁合金筒體環(huán)焊縫焊接殘余變形，筒體焊縫及近縫區(qū)的縱向撓曲變形，當(dāng)預(yù)拉伸應(yīng)力σp=90%σ0.2時(shí)，施加預(yù)拉伸焊接焊縫的殘余變形下降了30%左右；焊件結(jié)構(gòu)對(duì)焊接殘余變形的影響不同于焊接殘余應(yīng)力，平板的殘余變形除了塑性外還有彈性撓曲，筒體由于
3、是回轉(zhuǎn)體不具備撓曲結(jié)構(gòu)條件，因此筒體的焊接殘余變形小于平板接殘余變形，由于筒體的焊接殘余變形較小，預(yù)拉伸焊接減小焊接殘余變形的幅度小于預(yù)拉伸焊接減小焊接殘余應(yīng)力的幅度。關(guān)鍵詞：數(shù)值模擬；有限元；筒體結(jié)構(gòu)；溫度場(chǎng)；殘余應(yīng)力；殘余變形；預(yù)拉伸IAbstractAbstractBasedontheexperimentofaluminumalloyplatebuttweldingseamwithpretension,numericalsimulationresearchabouttheinfluenceo
4、fresidualstressandstrainwithpre-drawingstressappliedtobarrelweldingseamisassumed.IntroducingFEM(FiniteElementMethod),buildingmodelwithsolidmodelbuildingmethod,uniformsurfaceheatsourcemodelandfreemeshgridwayareused.Themovementofheatsourceisachievedthro
5、ughtheloopsentenceincylindricalsystem.Numericalanalysisisappliedtodealwiththermalphysicalparametersof7075aluminumalloy.Regionaltemperatureandstrain-stressinweldingareaofaluminumalloybarrelaresimulatedwith3-Dreal-timedynamicsimulationanalysismethodwhen
6、theseamwasappliedrespectivelywithpretensionandnot.Thedisciplineofstrain-stressdistributingintheprocessofaluminumalloybarrelweldingisdiscussed.Theinfluenceofstress-straininbarrelweldingwithpretensionisalsodiscussed.Withtheresultofnumericalsimulationana
7、lysis,it’sclearthattheresidualstressandresidualstrainwerecontrolledeffectivelywithpre-drawingstressinaluminumalloybarrelwelding.Thepeakofresidualstressisdeclinedwhenpre-stressis90%σ0.2.Verticalresidualstressdistributedcurveisflattenedinbarrelfracturep
8、laneandtheresidualstressdroppedby50%.Weldingwithpre-stressisaneffectivewaytocontrolresidualstressanddeflectiondeforminaluminumalloybarrelwelding.Theresidualstrainofweldingseamwithpre-stressdeclined30%.Theinfluenceofweldingstructureonweldingres
