混合模式下自冲铆接铝接头的疲劳寿命估算【中文7490字】
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- 关 键 词：
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混合
模式
铆接
接头
疲劳
寿命
估算
中文
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混合模式下自冲铆接铝接头的疲劳寿命估算【中文7490字】,混合,模式,铆接,接头,疲劳,寿命,估算,中文
- 内容简介：
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INTERNATIONALJOURNALOFFATIGUE9720172028TECHNICALNOTEFATIGUELIFEESTIMATIONOFSELFPIERCINGRIVETEDALUMINUMJOINTSUNDERMIXEDMODELOADINGDUKHOCHOIA,DONGWOONHANA,HOKYUNGKIMB,AGRADUATESCHOOL,DEPARTMENTOFAUTOMOTIVEENGINEERING,SEOULNATIONALUNIVERSITYOFSCIENCEANDTECHNOLOGY,REPUBLICOFKOREABDEPTOFMECHANICALANDAUTOMOTIVEENGINEERING,SEOULNATIONALUNIVERSITYOFSCIENCEANDTECHNOLOGY,SEOUL139743,REPUBLICOFKOREAARTICLEINFOARTICLEHISTORYRECEIVED9SEPTEMBER2016RECEIVEDINREVISEDFORM9DECEMBER2016ACCEPTED12DECEMBER2016AVAILABLEONLINE18DECEMBER2016KEYWORDSSPRJOINTSFATIGUELIFETIMECROSSSHAPEDSPECIMENMIXEDMODEEQUIVALENTSTRESSINTENSITYFACTORABSTRACTFATIGUETESTSWERECONDUCTEDUSINGCROSSSHAPEDSPECIMENSWITHALUMINUMALLOYAL5052PLATESMIXEDMODELOADINGWASACHIEVEDWITHDIFFERENTLOADINGANGLESOF0,45,AND90TOEVALUATETHEFATIGUESTRENGTHOFTHESELFPIERCINGRIVETEDSPRJOINTSUNDERMIXEDMODELOADINGONTHEBASISOFALIFETIMEOF106CYCLES,THELOADAMPLITUDESCORRESPONDINGTOTHEFATIGUELIMITWERE37,18,AND19OFTHEMONOTONICSTRENGTHFORLOADANGLESOF0,45,AND90,RESPECTIVELYTHEEQUIVALENTSTRESSINTENSITYFACTORCANAPPROPRIATELYPREDICTTHEEXPERIMENTALFATIGUELIFETIMESOFSPRJOINTSASLONGERTHAN105CYCLES。2016ELSEVIERLTDALLRIGHTSRESERVED1INTRODUCTIONRECENTLY,THEAUTOMOBILEINDUSTRYHASBEENACTIVELYWORKINGTOMAKETHEIRAUTOMOBILESLIGHTERINORDERTOIMPROVETHEFUELEFFICIENCYOFTHEIRPRODUCTSASAMEANSOFREDUCINGTHEWEIGHTOFAUTOMOBILES,LIGHTWEIGHTMATERIALSWITHEXCELLENTMECHANICALPROPERTIESAREFREQUENTLYUSED,INCLUDINGALUMINUMANDMAGNESIUMALLOYS,HIGHTENSILESTEEL,CARBONFIBERREINFORCEDCOMPOSITES,ANDENGINEERINGPLASTICSINADDITION,FORTHEAPPLICATIONOFTHESELIGHTWEIGHTMATERIALS,MANYSTUDIESHAVERECENTLYBEENCONDUCTEDOFVARIOUSJOININGMETHODSFORUSEWITHTHESEMATERIALS1INGENERAL,SPOTWELDINGISWIDELYUSEDASAJOININGMETHODFORVEHICLESHOWEVER,ITISDIFFICULTTOAPPLYSPOTWELDINGTOJOINTSCONSISTINGOFMATERIALSOFDIFFERENTTYPES,SUCHASAJOINTBETWEENALUMINUMANDSTEEL,DUETOTHECONSIDERABLEDIFFERENCESINTHEIRMELTINGTEMPERATURESANDCRYSTALMICROSTRUCTURESFURTHER,WHENJOININGCOMPOSITEMATERIALSORPLASTICSWITHSTEELSHEETS,SPOTWELDINGATYPEOFRESISTANCEWELDINGCANNOTBEAPPLIEDDUETOTHENONCONDUCTIVITYOFCOMPOSITEMATERIALSANDPLASTICSTHEREFORE,THEREISHIGHDEMANDFORJOININGTECHNOLOGIESWHICHCANBEUSEDWITHVARIOUSMATERIALSORWITHTHOSETOWHICHSPOTWELDINGCANNOTBEEASILYAPPLIEDASONESUCHTECHNOLOGY,THESELFPIERCINGRIVETINGSPRMETHODISGAININGMUCHATTENTIONCORRESPONDINGAUTHOREMAILADDRESSKIMHKSEOULTECHACKRHKKIMTHESPRJOININGPROCESSISSCHEMATICALLYSHOWNINFIG1INTHESPRJOININGPROCESS,ARIVETISPRESSEDINTOANUPPERSHEETUNDERAPUNCHINGFORCETHERIVET,WHICHPASSESTHROUGHTHEUPPERSHEET,ISSPLITTOJOINTHEUPPERANDTHELOWERSHEETSACCORDINGTOTHESHAPEOFTHEMOLDDIEONTHELOWERPORTIONOFTHESHEETASTHISPROCESSISSIMPLERTHANCONVENTIONALRIVETBASEDJOININGMETHODS,PRODUCTIVITYISINCREASEDMOREOVER,BECAUSEITISAJOININGMETHODWHICHISCONDUCTEDINACOLDSTATEWITHOUTAHEATTREATMENT,ITDOESNOTCAUSEDAMAGETOTHEPAINTINGORCOATINGOFASHEETTHEREHAVEBEENSEVERALPUBLISHEDRESULTS212ONTHEFATIGUEBEHAVIOROFSPRJOINTSOVERTHEPASTTENYEARSHUANGETAL2INVESTIGATEDTHEFATIGUEANDFRETTINGOFALUMINUMANDSTEELSHEETSTHEYREPORTEDTHATCRACKINITIATIONDUETOFRETTINGWEARINANALUMINUMSHEETWASTHEDOMINANTFAILUREMODEANDTHATTHECRACKINITIATIONLIFETIMEWASMUCHSHORTERTHANCRACKGROWTHLIFETIMECHUNGANDKIM3INVESTIGATEDTHEFATIGUEOFSPRJOINTSINLAPSHEARSPECIMENSOFALUMINUMANDSTEELSHEETSTHEYREPORTEDTHATCRACKINITIATIONOCCURREDATTHEALUMINUMSHEET,WHICHHADARELATIVELYLOWERSTRENGTHTHANSTEELSHEET,DUETOFRETTINGANDTHATTHEFATIGUESTRENGTHOFASPRJOINTWITHALUMINUMANDSTEELSHEETSCANBEDETERMINEDSIMPLYBYTHEFATIGUEPROPERTIESOFTHELOWERALUMINUMSHEETLIETAL4INVESTIGATEDTHEINFLUENCEOFFATIGUEONTHESTIFFNESSANDREMAININGSTATICSTRENGTHSOFSPRJOINTSUSINGTENSILESHEARANDPEELTENSIONSPECIMENSTHEYREPORTEDTHATFATIGUEINCREASEDTHEREMAININGSTATICSTRENGTHOFTENSILESHEARSPECIMENSDUETOTHEINCREASEDFRICTIONFORCEBETWEENTHEUPPERANDLOWERSHEETSKANGANDKIM5EVALUATEDAL5052SPRJOINTSWITHHTTP/DXDOIORG/101016/JIJFATIGUE20161201901421123/。2016ELSEVIERLTDALLRIGHTSRESERVEDCONTENTSLISTSAVAILABLEATSCIENCEDIRECTINTERNATIONALJOURNALOFFATIGUEJOURNALHOMEPAGEWWWELSEVIERCOM/LOCATE/IJFATIGUEDHCHOIETAL/INTERNATIONALJOURNALOFFATIGUE972017202821FIG1ANILLUSTRATIONOFSELFPIERCINGRIVETINGPROCESSDIFFERENTSPECIMENCONFIGURATIONSTHEYREPORTEDTHATTHERATIOSOFTHEFATIGUEENDURANCELIMITTOTHESTATICSTRENGTHWERE11,14AND34FORTHECOACHPEEL,CROSSTENSIONANDTENSILESHEARGEOMETRIES,RESPECTIVELYTHEYPREDICTEDTHESESPECIMENLIFETIMESQUANTITATIVELYUSINGTHEEQUIVALENTSTRESSINTENSITYFACTORRANGESKORUPAETAL6INVESTIGATEDTHEEFFECTOFFRICTIONONTHEFATIGUEBEHAVIOROFLAPJOINTSTHROUGHATHINTEFLONINTERFOILINTHEOVERLAPAREAINORDERTOMINIMIZEFRICTIONBETWEENTHESHEETSTHEYARGUEDTHATRIVETEDCOUPONSWITHOUTATEFLONINTERLAYERHADINFERIORFATIGUELIFETIMESCOMPAREDTOTHOSEWITHANINTERLAYERDUETOTHEOVERALLDETRIMENTALINFLUENCEOFTHELOADTRANSFERBYFRICTIONSUETAL7INVESTIGATEDTHEFATIGUEBEHAVIOROFSPRANDCLINCHJOINTSINTENSILESHEARSPECIMENSOFALUMINUMSHEETSTHEYREPORTEDTHATFATIGUECRACKSSTARTEDFROMTHECURVEDINTERFACIALSURFACEOFTHEUPPERSHEETANDTHENGROWINTOTHEUPPERSHEETFORTHESEJOINTSTHEYALSODEMONSTRATEDTHATTHEEXPERIMENTALFATIGUELIFETIMESOFTHESEJOINTSCANBEESTIMATEDUSINGSTRUCTURALSTRESSSOLUTIONSFUANDMALLICKINVESTIGATEDTHEFATIGUEOFSPRINANAL6111T4ALUMINUMALLOY,ADOPTINGTENSILESHEARSPECIMENGEOMETRY8THEYOBSERVEDTHATTHERIVETSETTINGPRESSUREINFLUENCEDTHESTATICFAILURELOADBUTNOTTHEFATIGUESTRENGTHTHEYALSOREPORTEDTHATFATIGUEPRECYCLINGUPTO75OFTHEFATIGUELIFETENDEDTOGRADUALLYDETERIORATETHEJOINTSTRENGTH,BUTABOVE90OFTHEFATIGUELIFETHEREWASASUDDENDECREASEINJOINTSTRENGTHSUNETALINVESTIGATEDFATIGUEBEHAVIOROFSPRJOININGSIMILARANDDISSIMILARSHEETMATERIALS,ADOPTINGTENSILESHEARANDCROSSTENSIONSPECIMENGEOMETRIES9THEYALSOINVESTIGATEDTHEINFLUENCESOFMATERIALGRADES,MATERIALTHICKNESS,PIERCINGDIRECTIONANDTHEUSEOFSTRUCTURALADHESIVEONTHEFATIGUEBEHAVIORSOFTHESPECIMENSTHEYREPORTEDTHATSPRJOINTSHADSUPERIORFATIGUESTRENGTHTORESISTANCESPOTWELDJOINTSFORTHESAMEMATERIALCOMBINATIONSANDTHATTHEAPPLICATIONOFSTRUCTURALADHESIVESIGNIFICANTLYENHANCEDTHEFATIGUESTRENGTHOFTHEJOINTSAMPLESHOWEVER,MOSTOFTHEPUBLISHEDSTUDIESONTHEFATIGUEBEHAVIOROFSPRJOINTSHAVEFOCUSEDONTHEFATIGUESTRENGTHANDLIFETIMESWITHCONVENTIONALSHAPEDSPECIMENS,SUCHASTENSILESHEAR212,CROSSTENSION5,ORCOACHPEEL4,5,9,11,12SPECIMENSRESEARCHREMAINSINSUFFICIENTWITHREGARDTOEVALUATIONSOFTHEFATIGUESTRENGTHOFSPRSPECIMENSINDIFFERENTLOADMODESINMOSTCASES,WHENEVALUATINGTHEFATIGUESTRENGTHOFSPRJOINTS,THELOADAMPLITUDEISUSEDASAPARAMETERHOWEVER,INTHECASEOFTHELOADAMPLITUDE,ANACCURATECOMPARISONISDIFFICULTWHENTHETESTSPECIMENSHAVEDIFFERENTSHAPESANDDIMENSIONSEVENFORTHESAMERIVETDIAMETER,SHEETMATERIAL,ANDSHEETTHICKNESS,THEFATIGUESTRENGTHINTERMSOFTHELOADAMPLITUDEDIFFERSFROMONESPECIMENTYPETOANOTHERTOADDRESSTHISPROBLEM,ITISNECESSARYTODEVELOPAUNIFIEDPARAMETERWHICHCANBEUSEDTOEVALUATETHEFATIGUESTRENGTHLEVELSOFSPRJOINTSREGARDLESSOFTHEDIMENSIONSAND/ORSHAPESOFTHETESTSPECIMENSINTHISSTUDY,ONLYACROSSSHAPEDSPECIMENWILLBEADOPTEDFORSPRJOINTSTOMEASURETHEFATIGUESTRENGTHINVARIOUSLOADCONDITIONSWHILEVARYINGTHELOADINGANGLETODOTHIS,CROSSSHAPESPECIMENSMADEOFANAL5052SHEETAREUTILIZEDINANEVALUATIONOFTHEMONOTONICANDTHEFATIGUESTRENGTHOFSPECIMENSTHROUGHSTATICANDFATIGUETESTSATLOADANGLESOF0,45,AND90WITHAMIXEDMODELOADJIGINADDITION,THECOMMERCIALFINITEELEMENTMETHODFEMPROGRAMABAQUSISUSEDTOCONDUCTASTRUCTURALANALYSISOFTHERESPECTIVELOADANGLESMEANWHILE,THEMAXIMUMPRINCIPALSTRESS,VONMISESSTRESS,ANDEQUIVALENTSTRESSINTENSITYFACTORAREUSEDASPARAMETERSTOCORRELATETHEFATIGUELIFETIMESOFTHESPECIMENSATEACHOFTHELOADANGLES2TESTSPECIMENANDTESTMETHODS21SPRTESTSPECIMENINEXPERIMENTALINVESTIGATIONSOFTHEFATIGUESTRENGTHOFSPOTJOINTS,FATIGUESTRENGTHTESTSAREUSUALLYCONDUCTEDONTENSILESHEAR,CROSSTENSION,COACHPEEL,USHAPED13,ANDHSHAPEDSPECIMENS14TOPRODUCECOACHPEEL,USHAPEDANDHSHAPEDSPECIMENSOFMATERIALSWITHLOWDUCTILITY,ITISDIFFICULTTOBENDTHECOUPONFOREXAMPLE,INORDERTOPRODUCETHECOACHPEELSPECIMEN,ITISNECESSARYTOBENDTHECOUPONTOANL”SHAPEHOWEVER,THEREISAPOSSIBILITYOFCRACKINGATTHEBENTREGIONDURINGTHEBENDINGPROCESSANDEVENDURINGTHEFATIGUETESTPRIORTOTHEFINALFATIGUEFRACTUREATTHEBENTREGIONTHEREFORE,INORDERTOAVOIDSUBJECTINGTHECOUPONTOABENDINGPROCESSINPREPARINGTHESPECIMEN,WEDESIGNEDACROSSSHAPEDSPRJOINTSPECIMENSIMILARTOTHECROSSTENSIONSPECIMENSUSEDINSPOTWELDING,ASSHOWNINFIG2THISSPECIMENISPROPOSEDTOEVALUATETHEFATIGUESTRENGTHOFSPRJOINTSUNDERMIXEDMODELOADINGCONDITIONSWITHCHANGESOFTHELOADINGANGLETHISSPRSPECIMENCANBEAPPLIEDTOMATERIALSWHICHCANNOTBEBENT,SUCHASCOMPOSITEMATERIALSANDVARIOUSALLOYSWITHLOWDUCTILITYINTHISSTUDY,AL5052H32WASUSEDASTHEMATERIALOFTHESPRJOINTSFORTHERIVETS,THEC50541TYPEBYHENROBLTDWASUSEDTHISTYPECONSISTSOFMEDIUMCARBONSTEEL035WTWITHANALUMINUMSURFACETREATMENTALMACBOTHTHEDIAMETERANDLENGTHOFTHESHANKOFTHERIVETWERE53MMTHEBONDINGSTRENGTHSOFSPRJOINTSVARYGREATLYACCORDINGTOCERTAINDIMENSIONS,SUCHASTHETHICKNESSOFTHESHEETS,THEDIAMETEROFTHERIVETS,THESHAPEOFTHEDIEUSED,ANDTHEPUNCHINGFORCEDURINGTHERIVETINGPROCESSINTHISSTUDY,UPPERANDLOWERSHEETSWITHTHICKNESSESOF15MMWEREUSEDALLOFTHESPRSPECIMENSFORFATIGUETESTINGWEREPREPAREDFORAPUNCHINGFORCEOF21KNBYREFERRINGTOTHERESULTSOFANEARLIERSTUDY5WHICHDETERMINEDTHEOPTIMALPUNCHINGFORCEBASEDONTHEUSEOFTENSILESHEARSPEC22DHCHOIETAL/INTERNATIONALJOURNALOFFATIGUE9720172028FIG2GEOMETRIESANDDIMENSIONSOFTHECROSSSHAPEDSPRSPECIMENSIMENSWITHTHESAMEALLOYSHEETSANDATATHICKNESSIDENTICALTOTHATUSEDINTHISSTUDYINORDERTOEVALUATETHEMECHANICALPROPERTIESFORTHEFINITEELEMENTANALYSISOFSPRJOINTS,ATENSILETESTWASCARRIEDOUTBYPRODUCINGTENSILESPECIMENSTHEMECHANICALPROPERTIESOFTHEMATERIALUSEDARESUMMARIZEDINTABLE122MIXEDMODETESTJIGAMIXEDMODETESTJIGWASDESIGNED,ASSHOWNINFIGS3AND4,FORTHEFATIGUETESTATLOADANGLESOF0,45AND90USINGACROSSSHAPEDTESTSPECIMENWHENTHELOADANGLEIS0,ITISSIMILARTOALOADONATENSILESHEARSPECIMENINTHESPOTWELDINGWHENTHELOADANGLEIS90,ITISVERYSIMILARTOTHECROSSTENSIONSPECIMENINTHESPOTWELDING23TESTMETHODSINORDERTOEVALUATETHESTATICSTRENGTHANDFATIGUESTRENGTHOFSPRJOINTS,AHYDRAULICUNIVERSALTESTINGMACHINEINSTRON8516WASUSED,ASSHOWNINFIG5THEFATIGUETESTSWEREPERFORMEDBYAPPLYINGAREPEATEDLOADINTHESINEWAVEFORMWITHASTRESSRATIORPMIN/PMAXOF01WITHINAFREQUENCYRANGEOF25HZ24STRUCTURALANALYSISMODELINGASPRJOINTSPECIMENCONSISTSOFANUPPERSHEET,ALOWERSHEET,ARIVET,ANDAPIECETOBESHEAREDANDSEPARATEDFROMTHEUPPERSHEETATTHETIMEOFTHESPRJOININGFORASTRUCTURALANALYSIS,ATHREEDIMENSIONALFINITEELEMENTMODELWASAPPLIEDTHESCALEVALUEOFTHECROSSSECTIONALIMAGEASDETERMINEDBYMEASURINGTHERIVETFIG3RESOLVEDCOMPONENTSPANDQATTHESPRJOINTWITHTHEMIXEDMODETESTJIGFORAGENERALAPPLIEDLOADFFIG4LOADINGANGLEFORTHESPRJOINTONTHECROSSSECTIONOFTHESPRJOINTWASAPPLIEDBASEDONTHIS,THEJOINTPARTWASMODELEDASSHOWNINFIG6FINALLY,REFERRINGTOFIG7,ATHREEDIMENSIONALMODELOFTHESPRJOINT,CORRESPONDINGTOTHECENTRALPARTOFTHECROSSSHAPEDSPECIMEN,WASCOMPLETEDINCONDUCTINGFEMANALYSIS,ANONLINEARKINEMATICHARDENINGELASTICPLASTICMATERIALMODELWASUSEDTOREPRESENTSTRESSSTRAINBEHAVIOROFAL5052H32SHEETMATERIALTHETRUEANDENGINEERINGSTRESSSTRAINCURVESATACONSTANTCROSSHEADSPEEDOF5MM/MINARESHOWNINFIG8THEELASTICMODULUSEANDPOISSONSRATIOMWEREMEASUREDTOBE72GPAAND03,RESPECTIVELYFORTHESTEELTABLE1MECHANICALPROPERTIESOFTHEAL5052H32MATERIALMATERIALRFMPARUTSMPARYMPAELONGAL5052H322344215516189DHCHOIETAL/INTERNATIONALJOURNALOFFATIGUE972017202823FFFFIG5FATIGUETESTINGJIGUSEDFORTHESPRJOINTFATIGUESTRENGTHEVALUATIONUNDERMIXEDMODELOADINGCONDITIONSRIVETMODEL,HOWEVER,ALINEARELASTICMATERIALRELATIONSHIPWASADOPTEDWITHE210GPAANDM030INTHISSTUDY,HYPERMESHWASUSEDASTHEPREPROCESSORANDPOSTPROCESSOR,ANDABAQUSWASUSEDASTHESOLVERFORMODELING,C3D6ANDC3D8,WHICHARESOLIDELEMENTS,WEREAPPLIED,ANDTHEBOUNDARYCONDITIONSWEREDETERMINEDFOREACHOFTHELOADANGLES0,45AND90THENUMBEROFNODESANDELEMENTSOFTHECROSSSHAPEDSPECIMENMODELWERE52,840AND43,904,RESPECTIVELYTHEFRICTIONCOEFFICIENTBETWEENTHERIVETANDTHESHEETWASSETTO02,ANDTHEFRICTIONCOEFFICIENTBETWEENTHESHEETSWASSETTO015THELOADWASAPPLIEDTOTHELOWERSHEET,ANDTHEANALYSISWASCONDUCTEDWITHTHEUPPERSHEETFIXED3EXPERIMENTALRESULTSANDDISCUSSION31STATICSTRENGTHOFSPRJOINTSFIG9SHOWSTHESTATICFORCEANDDISPLACEMENTASARESULTOFTHESTATICSTRENGTHTESTING,WHERELOADANGLESOF0,45AND90WEREAPPLIEDTOTHECROSSSHAPEDSPRSPECIMENSTHEMAXIMUMLOADSFORTHELOADANGLESOF0,45AND90WERE3571N,1850N,1503N,RESPECTIVELYINADDITION,ITWASOBSERVEDTHATAFTERREACHINGTHEMAXIMUMPOINT,SEPARATIONBETWEENTHEUPPERANDLOWERSHEETSTOOKPLACEASTHELOADANGLEWASINCREASEDFROM0TO45ANDTO90,THESTRENGTHDECREASEDBY48AND58,RESPECTIVELYASTHELOADANGLEWASINCREASED,ITISLIKELYTHATTHESTRENGTHWASGREATLYAFFECTEDBYTHEBENDINGMOMENTATTHESPRRIVETCAUSEDBYTHELOADATBOTHENDSOFTHESPECIMENWHENTHELOADANGLEIS0,THESTRENGTHISATITSHIGHESTPOINTASISTHECASEFORSPOTWELDEDJOINTS,SPRJOINTSAREVULNERABLETOALOADWHICHISPARALLELTOTHEAXIALDIRECTIONOFTHESPRRIVETSHANK32FATIGUELIFETIMESOFSPRJOINTSAFATIGUETESTOFACROSSSHAPEDSPECIMENWASCONDUCTEDFORTHELOADANGLESOF0,45AND90WHILEVARYINGTHELOADAMPLITUDESTHEOCCURRENCEOFFATIGUEFAILUREWASDETERMINEDTOBETHETIMEPOINTWHENACRACKOFAPPROXIMATELY5MMWASOBSERVEDAROUNDTHERIVETINGAREATHEFATIGUELIFETIMESARESUMMARIZEDINTABLE2FIG10SHOWSTHERELATIONSHIPBETWEENTHELOADAMPLITUDEPAMPANDTHEFATIGUELIFETIMEFORTHELOADANGLESOF0,45AND90THERELATIONSHIPBETWEENTHELOADAMPLITUDEANDTHENUMBEROFCYCLESNFWASPAMP19974N0029FORTHESPECIMENTESTEDATALOADANGLEOF0,PAMP27911N0152FORTHESPECIMENTESTEDATALOADANGLEOF45,ANDPAMP10229N0093INTHECASEOFTHESPECIMENTESTEDATALOADANGLEOF90THELOADAMPLITUDECORRESPONDINGTOTHEFATIGUELIMIT,BASEDONA106CYCLELIFETIME,WAS1338N,342N,AND283NFORTHELOADANGLESOF0,45AND90,RESPECTIVELYTHISFATIGUELIMITCORRESPONDSTO37OFTHESTATICSTRENGTHP3571NFORTHELOADANGLEOF0WHENTHELOADANGLEWAS45,THEFATIGUELIMITISAPPROXIMATELY18OFTHESTATICSTRENGTHP1850N,ANDWHENTHELOADANGLEIS90,THELOADAMPLITUDEFATIGUELIMITISCLOSETO19OFTHESTATICSTRENGTHP1503NACCORDINGTOTHEFATIGUETESTRESULTSFORSPRJOINTSWITHAL5052ALLOYASTHEUPPERSHEETANDCOLDROLLEDSTEELASTHELOWERSHEET3,15,THELOADAMPLITUDE,CORRESPONDINGTOTHEFATIGUESTRENGTHAT106CYCLES,OFTHETENSILESHEARANDCROSSTENSIONSPECIMENSWAS35AND14OFTHESTATICSTRENGTHOFTHESPECIMENS,RESPECTIVELYTHESEVALUESARECLOSETOTHEPRESENTRESULTSOF37AND19FORTHECORRESPONDINGLOADINGANGLESOF0AND9033RESULTSOFTHESTRUCTURALANALYSISOFSPRJOINTSASTRUCTURALANALYSISWASCONDUCTEDWITHLOADANGLESOF0,45AND90OFACROSSSHAPEDSPECIMENFIG11SHOWSTHEMAXIMUMVONMISESSTRESSDISTRIBUTIONWHENTHEMAXIMUMLOADPMAX,CORRESPONDINGTOTHEFATIGUELIFETIMEOF106CYCLES,WASAPPLIEDFORALOADANGLEOF0ASSHOWNINFIG11A,THEMAXIMUMSTRESSWAS279MPAATTHELOADANGLEOF0THISMAXIMUMSTRESSEXCEEDSTHEYIELDSTRENGTH1618MPAANDTHETENSILESTRENGTH2155MPAOFTHEMATERIALUSEDINTHISSTUDYTHISIMPLIESTHATTHESTRENGTHOFTHEJOINTINCREASEDDUETOCOLDWORKHARDENINGDURINGTHERIVETINGSTEPCOMPRESSIVECIRCUMFERENTIALRESIDUALSTRESSAROUNDTHEPIERCEDHOLESISALSOEXPECTEDTOBECREATEDDURINGTHESPRPROCESSTHISFIG6CROSSSECTIONOFA3DFEAMODELOFASPRJOINT24DHCHOIETAL/INTERNATIONALJOURNALOFFATIGUE9720172028FIG73DFEAMODELSOFASPRJOINTSPECIMENFIG8TENSILESTRESSSTRAINCURVESFORTHEAL5052H32SHEETSITUATIONISSIMILARTOTHECASEOFTHECOLDWORKTECHNIQUEUSEDINTHEAERONAUTICALINDUSTRYTOCREATECOMPRESSIVERESIDUALSTRESSINTHISTECHNIQUE,COMPRESSIVECIRCUMFERENTIALRESIDUALSTRESSISCREATEDAROUNDTHERIVETHOLESBYAPPLYINGPRESSUREONTHEHOLESURFACEBYMEANSOFAMANDREL16FORTHESPRJOINT,THEAPPLIEDPRESSUREONTHEPIERCEDHOLESURFACEDUETOCOLDEXPANSIONPLASTICIZESTHEMATERIALSURROUNDINGTHEHOLE,WHICHRESULTSINDISTRIBUTIONOFCOMPRESSIVERESIDUALAROUNDTHEPIERCEDHOLE17FINALLY,THERESIDUALSTRESSISEXPECTEDTOCONTRIBUTETORETARDINGCRACKINITIATIONANDGROWTHINTHESPRJOINTHOWEVER,INTHISSTUDY,THECOMPRESSIVERESIDUALSTRESSWASNOTTAKENINTOACCOUNTDURINGTHEFEMANALYSISTHEREFORE,THEVALUEOFTHEMAXIMUMSTRESSAROUNDTHESPRJOINT,ASSHOWNINFIG11,ISEXPECTEDTOBELOWERTHANTHATOFTHEACTUALJOINTDURINGTHEFATIGUETESTTHELOCATIONOFTHEMAXIMUMVALUEWASTHEPOINTATWHICHTHERIVETANDTHEUPPERSHEETCAMEINTOCONTACT,ANDTHELOCATIONSHIFTEDTOWARDTHERIVETHEADASTHELOADANGLEINCREASEDTHELOCATIONOFTHEMAXIMUMVALUEATTHEANGLEOF90WASTHEPOINTWHERECONTACTWASMADEBETWEENTHERIVETHEADANDTHEUPPERSHEETMEANWHILE,ASSHOWNINFIG11BANDC,THEMAXIMUMSTRESSLEVELSWERE251MPAAND799MPA,RESPECTIVELY,ATTHELOADANGLESFIG9COMPARISONOFTHESTATICLOADVERSUSTHEDISPLACEMENTCURVESOFSPRSPECIMENSATDIFFERENTLOADINGANGLESOF45AND90ITWASCONFIRMEDTHATASTHELOADANGLESINCREASED,THEMAXIMUMSTRESSVALUESATTHELOADAMPLITUDES,CORRESPONDINGTOTHEFATIGUELIFETIMESOF106CYCLES,DECREASED34FATIGUEFAILUREMODEINMONOTONICTESTS,ARIVETWASPULLEDOUTOFTHELOWERSHEETWITHLARGEPLASTICDEFORMATIONNEARTHERIVETHOWEVER,ALLOFTHEFATIGUETESTEDSPECIMENSMAINLYFAILEDDUETOFATIGUEWITHCRACKGROWTHINTHEUPPERSHEET,ASSHOWNINFIG12FIG12ACSHOWSTHEFATIGUEFRACTUREMODEOFTHESPECIMENSATLOADINGANGLESOF0,45,AND90,RESPECTIVELYACCORDINGTOTHESTRUCTURALANALYSIS,THELOCATIONOFTHEMAXIMUMSTRESSWASTHEPOINTATWHICHTHERIVETANDTHEUPPERSHEETCAMEINTOCONTACTITTENDEDTOMOVETOWARDTHERIVETHEADASTHELOADANGLEINCREASEDTHESPECIMENAT0WITHPAMP1440NEXHIBITSANEYEBROWFAILUREMODE,ASSHOWNINFIG12AFORTHISSPECIMEN,AFATIGUECRACKGENERALLYINITIATEDDHCHOIETAL/INTERNATIONALJOURNALOFFATIGUE972017202825SPRJOINTSPLATEAL5052H32T15MM0O45O90OTABLE2SUMMARIZEDFATIGUETESTINGRESULTSLOADINGANGLEPAMPNNFCYCLESLOADINGANGLEPAMPNNFCYCLES0150019,5284548568,5000149036,88145450142,5720148069,93645400309,4950145027,38145370941,0370144028,3999039041,2610143070,5169038051,4440142087,2979036058,00201410405,2999035058,90301400786,96990340174,381013601,726,26490330272,826013501,670,55590320441,247012002,138,60390310670,2574570014,77490300421,7404565018,45490280803,9274560022,902902701,264,4444550064,115902602,310,2634549054,8831000WASPROPOSEDFORSPOTWELDTESTING14THELOADINGCONDITIONATTHESPOTWELDCANBEINVESTIGATEDWITHTHESAMESPECIMENBYCHANGINGTHELOADINGDIRECTIONTHEEQUIVALENTSTRESSINTENSITYFACTORFORTHESPECIMENISASFOLLOWS14S220637F2NBD2KEQDPTCOSHSINH12T21100104105106107NUMBEROFCYCLES,NFFIG10COMPARISONOFTHELOADAMPLITUDEAGAINSTTHENUMBEROFFAILURECYCLESPLOTSFORSPRJOINTSATDIFFERENTLOADINGANGLESONTHEFAYINGSURFACEOFTHEUPPERSHEET,SLIGHTLYAWAYFROMTHERIVETSHANKITTHENPROPAGATEDTHROUGHTHEUPPERSHEETTHICKNESSHERE,BISTHEWIDTHOFTHESPECIMEN30MM,HISTHELOADINGANGLE,NISACORRECTIONFACTOR,DISTHEDIAMETEROFANUGGET53MM,TISTHESPECIMENTHICKNESS15MMANDFISTHETOTALAPPLIEDFORCECORRECTIONFACTORNWASDETERMINEDTOBE128,CONSIDERINGECCENTRICITYEBD2FORTHECHRYSLERSPECIMENINTHISSTUDYWHENTHELOADINGANGLEHIS0,
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