轴对称件超塑约束胀形中的摩擦效应

轴对称件超塑约束胀形中的摩擦效应Abstract

Duringthesuperplasticformingprocessofaxisymmetriccomponentswithconstraintswelling,frictionaleffectsplayacrucialroleinthedeformationbehaviorandfinalproductquality.Thispaperinvestigatesthefrictionaleffectsonaxisymmetriccomponentsduringthesuperplasticformingprocesswithconstraintswelling.Anumericalsimulationwascarriedoutusingthefiniteelementmethodtoinvestigatetheeffectoffrictiononthedeformationbehaviorofasuperplasticaxisymmetriccomponentunderdifferentboundaryconditions.Itwasfoundthatthefrictionaleffectsignificantlyaffectedthedeformationbehaviorofthecomponent,andthefrictioncoefficienthadagreatinfluenceontheconstraintswellingprocess.Furthermore,theinfluenceofthefrictioncoefficientonthedistributionofstressandstrainwithinthecomponentduringthesuperplasticformingprocesswasanalyzed.

Keywords:superplasticforming,constraintswelling,axisymmetriccomponent,frictionaleffect,finiteelementmethod

Introduction

Superplasticformingisaversatileproductionprocessthatusestheplasticdeformationofamaterialataverylowstrainrateandhightemperaturetoformcomplexpartswithminimalpost-processingrequirements.Duringthesuperplasticformingprocess,thedeformationbehaviorofthematerialdependsonseveralfactors,includingthetemperature,strainrate,deformationhistory,andboundaryconditions.Moreover,thefrictionaleffectsattheinterfacebetweentheformingtoolandtheworkpieceplayacriticalroleindeterminingthefinalshapeandqualityoftheproduct.

Axisymmetriccomponentswithconstraintswellingarecommonlyusedintheaerospaceandautomotiveindustries.Intheseapplications,frictionaleffectscanhaveasignificantimpactonthedeformationbehaviorofthecomponent,resultinginqualityissuesandinconsistentproductperformance.Therefore,itisessentialtoinvestigatethefrictionaleffectsonaxisymmetriccomponentsduringthesuperplasticformingprocesswithconstraintswelling.

Inthispaper,anumericalsimulationwascarriedoutusingthefiniteelementmethodtoinvestigatetheeffectoffrictiononthedeformationbehaviorofasuperplasticaxisymmetriccomponentunderdifferentboundaryconditions.Theobjectiveofthisstudyistoanalyzethefrictionaleffectontheconstraintswellingprocessandthedistributionofstressandstrainwithinthecomponentduringthesuperplasticformingprocess.

Methodology

Thesuperplasticformingprocessofanaxisymmetriccomponentwithconstraintswellingwasmodeledusingthefiniteelementmethod.Thesimulationwasperformedusingatwo-dimensionalaxisymmetricnumericalmodelinABAQUS/Explicit.ThematerialusedinthesimulationwasTi-6Al-4V,whichisacommonmaterialusedinaerospaceapplications.ThematerialpropertiesusedinthesimulationareshowninTable1.

Table1:Materialpropertiesusedinthesimulation

ParameterValue

Young'smodulus(GPa)110

Poisson'sratio0.35

Thermalconductivity(W/mK)6.7

Specificheat(kJ/kgK)0.52

Density(kg/m^3)4430

Thecomponentwasassumedtobemadeofathinsheetwithathicknessof0.5mm.Theinitialgeometryofthecomponentwasdesignedasahollowcylinderwitharadiusof30mmandaheightof50mm,asshowninFigure1.

Thefrictioncoefficientbetweentheformingtoolandtheworkpiecewasvariedfrom0.0to0.3toinvestigateitseffectonthedeformationbehaviorofthecomponent.Theboundaryconditionswerealsovaried,withthecomponentbeingclampedatitsbaseinonecase,andfreeinanothercase.Thetemperatureoftheformingtoolwassetto890°C,andtheformingpressurewasappliedtothetopsurfaceofthecomponent.

ResultsandDiscussion

Theeffectoffrictiononthedeformationbehaviorofthecomponentwasanalyzedbycomparingthesimulateddeformationofthecomponentfordifferentfrictioncoefficientsandboundaryconditions.Figure2showsthecontourplotsoftheequivalentplasticstraindistributioninthecomponentforafrictioncoefficientof0.1underclampedandfreeboundaryconditions.

ItcanbeseenfromFigure2thatundertheclampedboundarycondition,thedeformationofthecomponentwasconstrained,resultinginarelativelyhighequivalentplasticstraininthecentralportionofthecomponent.However,underthefreeboundarycondition,thedeformationwasunconstrained,resultinginamorehomogeneousdistributionofequivalentplasticstrainthroughoutthecomponent.

Theinfluenceofthefrictioncoefficientontheconstraintswellingprocesswasalsoinvestigated.Itwasfoundthatasthefrictioncoefficientincreased,theconstraintswellingprocesswasinhibited,resultinginareducedfinalheightofthecomponent.Thisisduetothefactthatahigherfrictioncoefficientbetweentheformingtoolandtheworkpieceleadstoahigherfrictionalforce,whichopposesthedeformationofthematerial,andinhibitstheconstraintswellingprocess.

Finally,theinfluenceofthefrictioncoefficientonthedistributionofstressandstrainwithinthecomponentduringthesuperplasticformingprocesswasanalyzed.Itwasfoundthatthefrictionalforceattheinterfacebetweentheformingtoolandtheworkpieceresultsinahigherstressconcentrationnearthecontactarea,andhence,ahigherequivalentplasticstrainwithinthisregion.

Conclusion

Inthispaper,thefrictionaleffectsonaxisymmetriccomponentsduringthesuperplasticformingprocesswithconstraintswellingwereinvestigated.Anumericalsimulationusingthefiniteelementmethodwascarriedouttoinvestigatetheeffectoffrictiononthedeformationbehaviorofasuperplasticaxisymmetriccomponentunderdifferentboundaryconditions.Itwasfoundthatthefrictionaleffectsignificantlyaffectedthedeformationbehaviorofthecomponent,andthefrictioncoefficienthadagreatinfluenceontheconstraintswellingprocess.Furthermore,theinfluenceofthefrictioncoefficientonthedistributionofstressandstrainwithinthecomponentduringthesuperplasticformingprocesswasanalyzed.Theresultsofthisstudyprovideimportantinsightsintothedesignandoptimizationofthesuperplasticformingprocessforaxisymmetriccomponentswithconstraintswelling.Basedonthesimulationresults,itisclearthatfrictionaleffectsplayacriticalroleinthesuperplasticformingprocessofaxisymmetriccomponentswithconstraintswelling.Therefore,minimizingthefrictionalforcebetweentheformingtoolandtheworkpiececanleadtoimprovedproductqualityandenhancetheperformanceoftheentiremanufacturingprocess.

Onewaytomitigatetheeffectsoffrictionistoapplyalubricantattheinterfacebetweentheformingtoolandtheworkpiece.Theuseofalubricantreducesthefrictioncoefficient,resultinginlessdeformationresistanceandasmootherdeformationprocess.Additionally,propertooldesigncanalsominimizefrictionaleffects.Theuseofmaterialswithalowercoefficientoffrictionortheadditionofasurfacetreatmentcanalsohelpreducefrictionandimprovethequalityofthefinalproduct.

Inconclusion,theinvestigationoffrictionaleffectsonaxisymmetriccomponentsduringthesuperplasticformingprocesswithconstraintswellingiscrucialtoensurethequalityandconsistencyofthefinalproduct.Theresultsofthisstudycanbeusedtooptimizethesuperplasticformingprocessandreducecostsassociatedwithpost-processingoperations.Therefore,continuedresearchanddevelopmentinthisareawillbenefitthemanufacturingindustry.Anotherwaytominimizefrictionaleffectsduringthesuperplasticformingprocessistooptimizeprocessparameterssuchastemperature,strainrate,andappliedpressure.Theselectionoftheseparameterscanaffectthefrictionalforceandtheoveralldeformationbehavioroftheworkpiece.Forexample,increasingthetemperaturecanhelpreducefriction,asthematerialbecomessofterandmoremalleable.Additionally,reducingthestrainrateorincreasingtheappliedpressurecanalsohelpminimizefrictionaleffectsbyensuringamoreuniformdeformationprocess.

However,itisimportanttonotethatreducingfrictionshouldnotbedoneattheexpenseofotherimportantfactorssuchasformabilityandmechanicalproperties.Therefore,processoptimizationshouldtakeintoaccountallofthesefactorstoensurethatthefinalproductmeetsthedesiredspecifications.

Furthermore,modelingandsimulationtoolscanbeusedtopredictandanalyzefrictionaleffectsduringthesuperplasticformingprocess.Thesetoolscanprovidevaluableinsightsintothedeformationbehavioroftheworkpieceandassistinprocessoptimization.

Overall,minimizingfrictionaleffectsisacriticalaspectofthesuperplasticformingprocessforaxisymmetriccomponentswithconstraintswelling.Byoptimizinglubrication,tooldesign,processparameters,andusingmodelingandsimulationtools,manufacturerscanensureamoreconsistentandefficientsuperplasticformingprocess,whichcanleadtocostsavingsandimprovedproductquality.Inadditiontooptimizingprocessparametersandusingmodelingandsimulationtools,thereareadditionalmethodsthatcanbeusedtominimizefrictionaleffectsduringthesuperplasticformingprocess.Onesuchmethodistheuseofcoatingsorsurfacetreatmentsontheworkpieceoronthetooling.

Coatingsorsurfacetreatmentscanprovidealubricatinglayerbetweentheworkpieceandthetooling,reducingfrictionandimprovingtheoveralldeformationprocess.Thesecoatingscanbeappliedthroughvariousmethodssuchaselectroplating,physicalvapordeposition,orchemicalvapordeposition.

Anothermethodforreducingfrictionaleffectsistheuseofintermittentcontactsuperplasticforming(ICSF).InICSF,thetoolingisdesignedto