简介:Athree-dimensionalsimulationmodelfortheplasma-MIGweldingprocess,whichtakestheinteractionbetweentheplasmaarcandMIGarcintoaccount,ispresentedandthequasi-steadytemperaturefieldsontheworkpiecearecalculatedwiththemodel.The10mm-5A06aluminumalloyisweldedandthetemperaturefieldsaremeasuredwiththethermoelectriccouple.Thesimulationresultsandmeasuredresultsshowthatthebiggestdeviationofpeaktemperaturebetweenthemisbelow20℃,whichindicatesgoodcoincidencebetweenthesimulationandmeasurement.
简介:Theinfraredcameraisusedtoinvestigatethetemperaturefieldofgasmetalarcwelding.Theresultsshowthatthetemperaturedistributionofweldpoolandadjacentareaappearsconeshape.AnewheatsourcemodelcombinedbyGaussiandistributionheatsourceofthearcandconicaldistributionheatsourceofthedropletissetupbasedontheexperimentalresults,andwiththecombinedboundaryconditions,thetemperaturefieldofgasmetalarcweldingissimulatedusingfiniteelementmethod.AccordingtothecomparisonbetweentheresultsofexperimentandsimulationintemperaturefieldshowsthatthenewcombinedheatsourcemodelismoreaccurateandeffectivethantheGaussheatsourcemodel.
简介:Threekindsofmathematicalmodelsrepresentingweldingheatsourcesarepresented.Amongthem,Gaussianmodelanddoubleellipsoidalmodelareusedtoanalyzethethermaldistributionswithfiniteelementmethod.Atthesametime,thispaperanalyzedtheinfluencesoftheheatsourcemodels,thelatentheatandtheweldingparametersonthetemperaturedistributions.Thecomparisonsbetweenthesimulatedresultsandtheexperimentsshowdoubleellipsoidalmodelisgoodforthree-dimensionalnumericalsimulations.Furthermore,theadaptivemeshtechniqueisappliedinthethree-dimensionalmodelwhichgreatlyreducesthenumberofnodesandelementsinthesimulation.
简介:Theaccuratecalculationandmeasurementofweldingtemperaturefieldisanimportantpreconditionforweldingmetallurgicalanalysisandweldingprocesscontrolling.Inthispaper,theconformaltransformationisfirstlyusedtoanalyzetheweldingtemperaturefieldoffeatheredgedcylinder.Thecenterofthecylinderischosenastheoriginofcolumncoordinatesystem,andeverypointmaybeexpressedascomplexfieldvector.Thebranchisogonalitycounterchangesthelineparallelwiththefusionlineinhalf-infinitez-planetothecircleconcentricwiththefusionlineininfinitecylinder.TheLaplaceequationandPoisson'sequationstillkeepvalidity,sothetemperaturefieldequationcanbesolved.TheconformaltransformationandequationsolutionisprocessedbyMatlabprogramlanguage.Itshowsthattheobtainedanalyticalmodelingoftemperaturefieldforfeatheredgedcylinderbasedonconformaltransformationiseffectiveandaccurate.
简介:Theliquid-filmsolution-diffusionbondingofZCuBe2.5alloyswasconductedusingCu-basedalloypowders.Thetensilestrengthofthebondingtimedecreasesandtheinterfacemigrationvelocityincreasesbondingtime,thethicknessofdiffusionlayerincreaseswiththeincreaseoftemperaturegradient,andthistendencybecomesmoreremarkablewiththeprolongingofbondingtime.
简介:DeepcryogenictreatmenttechnologyofelectrodesisputforwardtoimproveelectrodelifeofresistancespotweldingofaluminumalloyLF2.Deepcryogenictreatmentmakeselectrodelifeforspotweldingaluminumalloyimprove.Thespecificresistivityofthedeepcryogenictreatmentelectrodesistestedandexperimentalresultsshowthatspecificresistivityisdecreasedsharply.ThetemperaturefieldandtheinfluenceofdeepcryogenictreatmentontheelectrodetiptemperatureduringspotweldingaluminiumalloyisstudiedbynumericalsimulationmethodwiththesoftwareANSYS.Theaxisymmetricfiniteelementmodelofmechanical,thermalandelectricalcoupledanalysisofspotweldingprocessisdeveloped.Thenumericalsimulationresultsshowthattheinfluenceofdeepcryogenictreatmentonelectrodetiptemperatureisverylarge.
简介:CreeppropertyofsolderalloysisoneoftheimportantfactorstoaffectthereliabilityofsolderedjointsinSMT(surfacemounttechnology).Particle-enhancementisawaytoimprovethepropertiesofsolderalloysandhascausedmuchmoreattentionthanbefore.Temperaturesappliedtosolderedjointsareoneoftheprimaryfactorsofaffectingcreeppropertiesofparticleenhancementcompositesolderedjoints.Inthispapersingleshearlapcreepspecimenswitha1mm2cross-sectionalareawerefabricatedusingCuparticleenhancement63Sn37Pbbasedcompositesolderedjointsand63Sn37Pbeutecticsolderedjointstoexaminetheinfluenceoftemperatureoncreepbehaviorofsolderedjoints.ResultsindicatedthatthecreepresistanceofsolderedjointsofCuparticleenhancement63Sn37Pbbasedcompositesolderedjointwasgenerallysuperiortothatoftheconventional63Sn37Pbsolderedjoint.Atthesametime,creeprupturelifeofthecompositesolderedjointwasdeclinedwithincreasingtemperatureanddropfasterthanthatoftheconventional63Sn37Pbeutecticsolderedjoint.
简介:Three-dimensionalfiniteelementmodelwasestablishedtosimulatetemperaturefieldsofT-jointtitaniumsheetsduringTIGweldingwithfiniteelementmethod(FEM)software.Temperaturedependentmaterialpropertiesandtheeffectoflatentheatwereconsidered.Atechniqueofelementbirthanddeathwasusedtosimulatetheprocessofweldedmetalfilling.DynamicvariationprocessoftemperaturefieldsduringTIGweldingwasachieved.Thesimulatedresultsagreedwellwiththemeasuredresults.
简介:TheunstabledimensionaldistortionofLF21aluminumalloyweldmentsatroomtemperatureandafterthermalcycleswasstudiedbyuseoflightinterferenceandCMM.Atthesametime,distortionmechanismwasanalyzedfromtheviewpointofmechanicsandmicrostructure.ExperimentalresultsshowthatthereexistsobviousdifferenceofunstabledimensionaldistortionbetweenLF21weldedspecimensundertwoconditionsmentionedabove.Underroomtemperature,dimensionalvariationofweldedspecimenswilldecreasegraduallyandfinallytendstobestableduring130hafterwelding.Therelativeelongationofweldedspecimenis4.2×10-5.Afterthermalcycles,distortionofweldedspecimenismuchlargerthanthatatroomtemperature.After11thermalcycles,thedimensionwilltendtobestable.Dimensionalunstabledistortionofweldmentsmainlyresultsfromtemperaturecondition,microstructurevariationandrelaxationofweldingresidualstress.
简介:Somepartswithcapillarytoplatejointhaveimportantapplicationinaerocraft.Vacuumelectronbeambrazing(VEBB)technologyisusedtorealizethisjointingwithcapillaries.Firstly3Dfiniteelementanalysismodelisbuiltinthispaperaccordingtothisspecialstructure.AndthenANSYSfiniteelementanalysissoftwareisusedtoanalyzebrazingtemperaturefieldatdifferentbrazingparameters.Thecalculationresultsshowthatthetemperaturefieldofsimulationhasgoodagreementwiththatmeasuredbyexperiment,whichprovesdependenceofthemodelbuiltinthispaper.Andalsoreferenceparameterscouldbeprovidedforrealbrazingprocessthroughcalculationinthismodel.BrazedjointofcapillarytoplatewithgoodperformanceisachievedusingVEBBtechnology.Theachievementofthestudywillbeappliedinaerocraftinthefuture.