铝和碳纤维增强聚合物片材的两步紧固【中文8873字】
收藏
资源目录
压缩包内文档预览：
编号：9734160
类型：共享资源
大小：8.99MB
格式：ZIP
上传时间：2018-03-24
上传人：闰***
认证信息
个人认证
冯**（实名认证）
河南
IP属地：河南
15
积分
- 关 键 词：
-
以及
碳纤维
增强
聚合物
紧固
中文
- 资源描述：
-
铝和碳纤维增强聚合物片材的两步紧固【中文8873字】,以及,碳纤维,增强,聚合物,紧固,中文
- 内容简介：
-
COMPOSITESTRUCTURES1642017180188TWOSTEPSCLINCHINGOFALUMINUMANDCARBONFIBERREINFORCEDPOLYMERSHEETSFRANCESCOLAMBIASEA,B,DAECHEOLKOCADEPTOFINDUSTRIALANDINFORMATIONENGINEERINGANDECONOMICS,UNIVERSITYOFLAQUILA,VIAGGRONCHI18,ZONAINDUSTRIALEDIPILE,67100AQ,ITALYBUNIVERSITYOFNAPLESFEDERICOII,CIRTIBSRESEARCHCENTRE,PLETECCHIO80,80125NAPLES,ITALYCGRADUATESCHOOLOFCONVERGENCESCIENCE,PUSANNATIONALUNIVERSITY,BUSAN46241,SOUTHKOREAARTICLEINFOARTICLEHISTORYRECEIVED27OCTOBER2016REVISED12DECEMBER2016ACCEPTED27DECEMBER2016AVAILABLEONLINE28DECEMBER2016KEYWORDSJOININGMETALCLINCHINGCFRPHYBRIDJOINTSCOMPOSITEABSTRACTTHEPRESENTPAPERINVESTIGATESTHEEFFECTIVENESSOFTWOSTEPSCLINCHINGFORJOININGALUMINUMANDCARBONFIBERREINFORCEDPOLYMERCFRPTOTHISEND,DIFFERENTRESHAPINGTOOLSWEREINVOLVEDAFTERJOININGBYCLINCHINGWITHSPLITDIESTHERESHAPINGFORCEWASALSOVARIEDSINGLELAPSHEARTESTSOFSIMPLECLINCHEDANDRESHAPEDSPECIMENSWEREPERFORMEDTODETERMINETHEINFLUENCEOFTHEPROCESSCONDITIONSONTHEMECHANICALBEHAVIOROFTHEJOINTSTHEMORPHOLOGYANDGEOMETRYOFJOINTSWEREANALYZEDTOUNDERSTANDHOWTHERESHAPINGSTEPINFLUENCESTHEMAINQUALITYCRITERIAOFTHEJOINTSANDTHEDAMAGEPRODUCEDONTHECFRPSHEETACCORDINGTOTHEEXPERIMENTALRESULTS,SIMPLECLINCHEDCONNECTIONFAILEDBYPULLOUTTHUS,THECRITICALPARAMETERWASTHEUNDERCUTTHERESHAPINGMETHOD,USINGOPTIMIZEDTOOLSENABLEDTOINCREASETHESTRENGTHOFTHEJOINTSBY32SUCHANIMPROVEMENTWASDUETOANINCREASEINTHEUNDERCUTTHATRESULTEDFROMAHIGHERANDIMPROVEDMATERIALFLOWTHEMAINDEFECTSTHATMAYAPPEARINTHESEJOINTSHAVEBEENIDENTIFIEDASWELLASTHEIRCAUSES。2016ELSEVIERLTDALLRIGHTSRESERVED1INTRODUCTIONHYBRIDMETALCOMPOSITESTRUCTURESAREMOREANDMOREEMPLOYEDINSEVERALFIELDSINCLUDINGTRANSPORTATIONINDUSTRIES,CIVILINFRASTRUCTUREANDCONSTRUCTIONASTHEYENABLEGREATREDUCTIONINPRODUCTWEIGHT,FUELSAVINGS,INERTIAREDUCTIONANDTHUSHIGHERPERFORMANCESAUTOMOTIVEINDUSTRIESAREINVESTINGHIGHEFFORTSTOREPRODUCEONLARGERSCALETHEBENEFITSOFUSINGHYBRIDMETALCOMPOSITECHASSISINRECENTYEARS,SUCHCHASSISAREBEINGEMPLOYEDONANUMBEROFVEHICLESOFMASSPRODUCTION,INCLUDINGALFAROMEO4C,BMW7SERIESANDCHEVROLETCORVETTEZ06HYBRIDMETALCOMPOSITESTRUCTURESAREALSOWIDELYEMPLOYEDINCIVILAPPLICATIONSWITHDIFFERENTSCOPESREINFORCINGBRIDGECONSTRUCTIONS1,INCREASINGFLEXURALRIGIDITYOFALUMINUMBEAMS2,REPAIRINGANDSTRENGTHENINGSTRUCTURALCOMPONENTS3ANDEVENPROTECTINGFROMFIREANDTHERMALLYINSULATINGLIGHTWEIGHTSTRUCTURALMATERIALS4BECAUSEOFTHEGREATDIFFERENCE,JOININGSUCHMATERIALSSTILLREPRESENTSACHALLENGINGISSUEANDITISGENERALLYMADEBYMEANSOFADHESIVEBONDINGANDMECHANICALJOININGPROCESSESCOMPAREDTOADHESIVEBONDS,MECHANICALJOINTSGENERALLYENSUREHIGHERSTATICCORRESPONDINGAUTHORATMONTELUCODIROIO,67040AQ,ITALYEMAILADDRESSFRANCESCOLAMBIASEUNIVAQITFLAMBIASEANDDYNAMICLOADCAPACITYINADDITION,THESEJOINTSAREPERFORMEDINSHORTERTIMEBECAUSETHEYDONOTREQUIREEXTENSIVESURFACEPREPARATIONINCLUDINGETCHING,GRINDING,ANDDEGREASING,ISENVIRONMENTALLYFRIENDLYDUETOLOWENERGYREQUIREMENTS,LOWNOISEANDFUMESEMISSIONANDDONOTREQUIRECURINGTIMEHOWEVER,MECHANICALJOININGPROCESSESUSUALLYREQUIREPRELIMINARYDRILLINGOFTHESHEETSTHATMAYDAMAGETHECOMPOSITEMATERIAL,CAUSEFIBERINTERRUPTION,ANDPRODUCESTRESSCONCENTRATIONALTHOUGHTHEYREQUIRESHORTERTIMEASCOMPAREDTOADHESIVEBONDING,MECHANICALJOININGPROCESSESINVOLVEMANUALSTEPSSUCHASPREDRILLINGANDSUBSEQUENTINSERTIONOFEXTRAJOININGELEMENTSANDREQUIREADDITIONALMATERIALRIVETS,BOLTS,ETCTHATINCREASETHEPRODUCTIONTIME,COSTS,ANDSTRUCTUREWEIGHTDESPITEOFMECHANICALJOINTS,ADHESIVEBONDINGENABLESENSURINGTHEINTEGRITYOFTHECOMPOSITEPARTNOFIBERSINTERRUPTIONISPRODUCEDANDTHELOADISDISTRIBUTEDMOREUNIFORMLYSINCETHEABSENCEOFHOLES5INTHISCASE,THESTRESSISALMOSTUNIFORMINWIDTHDIRECTIONWHILEITFOLLOWSAU”SHAPEDISTRIBUTIONALONGTHEBONDINGLENGTH6INTHESEJOINTS,THEDEBONDINGGENERALLYINITIATESATORNEARONEOFTHEBONDEXTREMITIES7COUPLINGMECHANICALJOININGANDADHESIVEBONDINGLEADINGTOHYBRIDJOINTSREPRESENTSANINTERESTINGIMPROVEMENT,SINCEITBRINGSTOGETHERTHEADVANTAGESOFBOTHTHESEJOININGTECHNOLOGIESHYBRIDJOININGHASPROVENTOIMPROVEBOTHTHESTATIC8ANDFATIHTTP/DXDOIORG/101016/JCOMPSTRUCT20161207202638223/。2016ELSEVIERLTDALLRIGHTSRESERVEDCONTENTSLISTSAVAILABLEATSCIENCEDIRECTCOMPOSITESTRUCTURESJOURNALHOMEPAGEWWWELSEVIERCOM/LOCATE/COMPSTRUCTFLAMBIASE,DCKO/COMPOSITESTRUCTURES1642017180188181GUESTRENGTH9,DUETOLOWERSTRESSCONCENTRATIONDEVELOPINGDURINGSERVICELIFEBECAUSEOFTHELARGEVARIETYOFMECHANICALJOININGPROCESSES,DIFFERENTMECHANICALCONNECTIONSCANBECOUPLEDWITHADHESIVEBONDING,INCLUDINGBOLTED8,RIVETED10,LASERRIVETING,ANDSELFPIERCERIVETS11SINCETHEINCREASINGEMPLOYMENTOFHYBRIDSTRUCTURESFORMASSPRODUCTIONS,FASTERJOININGPROCESSESAREREQUIREDANUMBEROFNEWPROCESSESHAVEBEENDEVELOPEDTOJOINFIBERREINFORCEDTHERMOPLASTICSFRICTIONSPOTJOINING12,FRICTIONLAPWELDING,13,ULTRASONICWELDING14,ANDLASERASSISTEDDIRECTJOINING15THESEPROCESSESPRODUCEMECHANICALANDCHEMICALADHESIONBETWEENTHETHERMOPLASTICMATRIXOFTHECOMPOSITEANDTHEMETALSURFACEINADDITION,ADVANCEDTHERMOFORMINGPROCESSES,WHICHPRODUCEAMECHANICALINTERLOCKBETWEENTHECOMPONENTSBYPLASTICALLYDEFORMINGTHECOMPOSITEAREALSOSUITABLEFORTHISPURPOSETHERMOFORMINGPROCESSESINCLUDEFRICTIONBASEDSTACKING16,INFRAREDSTACKING17,FRICTIONRIVETING18,ANDFLOWDRILLING19NEVERTHELESS,THESEPROCESSESARENOTSUITABLEFORJOININGCOMPOSITESWITHTHERMOSETTINGMATRICES,SINCETHEYWOULDPRODUCETHERMALDEGRADATIONOFTHEPOLYMERANDMECHANICALDAMAGEOFBOTHTHEFIBERANDTHEMATRIX,TEARINGOFTHEFIBERS,ANDDELAMINATIONOFTHECOMPOSITEONTHEOTHERHAND,FASTMECHANICALJOININGPROCESSESSUCHASCLINCHING2026ANDSELFPIERCERIVETING2729ENABLETOOVERCOMESOMEOFTHEABOVEMENTIONEDCONCERNSINDEED,DESPITEOFCOMMONMECHANICALJOININGMETHODS,WHICHINVOLVERIVETSANDBOLTS,BOTHTHESEPROCESSESDONOTREQUIREPRELIMINARYDRILLINGOFAHOLEINTHESHEETSBEINGJOINED30,31INADDITION,CLINCHINGENABLESADDITIONALADVANTAGES,ASITDOESNOTREQUIREEXTERNALJOININGELEMENTS,WHICHINVOLVEHIGHERCOSTSASWELLASINCREASETHESTRUCTUREWEIGHTMECHANICALCLINCHINGCONSISTSINTHEFORMATIONOFANUNDERCUTTHATFASTENSTWOORMORESHEETSTHEUNDERCUTISPRODUCEDBYAPLASTICDEFORMATIONBYUSINGAPUNCHANDADIECLINCHINGHASBEENORIGINALLYDEVELOPEDTOJOINMETALSHEETSINCLUDINGHIGHSTRENGTHSTEELSANDALUMINUMALLOYSTHEN,ITHASBEENEXTENDEDTOJOINADVANCEDMETALSMAGNESIUMANDTITANIUMALLOYS,ASWELLASTHERMOPLASTICPOLYMERS32,WOODMATERIALS33ANDALSOCOMPOSITESSHEETSWITHFIBERREINFORCEDPOLYMERFRPWITHTHERMOPLASTICMATRIXANDSHORTFIBERS34ANDTHERMOSETTINGMATRIX35WITHLONGFIBERSTHEPROPERDESIGNOFTHECLINCHINGTOOLSISAIMEDATINCREASINGTHEMAINJOINTQUALITYPARAMETERSTHEUNDERCUTANDTHENECKTHICKNESS,WITHOUTDAMAGINGTHESHEETS36MECHANICALCLINCHINGOFCOMPOSITESINTRODUCESFURTHERCONCERNSSINCEDELAMINATIONOFTHECOMPOSITESHOULDBEALSOLIMITEDORPOSSIBLYAVOIDEDTHUS,SPECIFICCONFIGURATIONSSUCHASHOLECLINCHINGHASBEENPROPOSED37,WHICHCONSISTSINPRELIMINARYDRILLINGOFTHECOMPOSITEHOWEVER,HOLECLINCHINGINTRODUCESFURTHERCONCERNSSUCHASLONGERPROCESSINGTIMESOWINGTOTHEPREDRILLINGOPERATION,ANDECCENTRICITYBETWEENTHEPUNCHANDTHEHOLE38FURTHERMORE,DURINGHOLECLINCHING,THEPUNCHSIDEDSHEETISSUBJECTEDTOHIGHERTEARINGSTRESSTHATMAYCOMPROMISETHEINTEGRITYOFTHESHEETSFORMATERIALSWITHPOORFORMABILITY39ASABOVEMENTIONED,THEMECHANICALBEHAVIOROFCLINCHEDJOINTSDEPENDSONGEOMETRICALCHARACTERISTICSTHEUNDERCUTANDTHENECKTHICKNESSTHATDEPENDSONTHEMATERIALFLOWTHUS,TOIMPROVETHESTRENGTHOFTHOSEJOINTS,DIFFERENTAPPROACHESAREPOTENTIALLYSUITABLEINCLUDINGTHEOPTIMIZATIONOFTHETOOLSSETS,ASWELLASTHEDEVELOPMENTOFATWOSTEPSCLINCHINGTHATINVOLVESARESHAPINGSTEPAFTERCLINCHINGTHELATTERMETHODHASBEENINITIALLYPROPOSEDTOREDUCETHEPROTRUSIONHEIGHTANDTHUSTOIMPROVETHEAESTHETICALCHARACTERISTICSOFSUCHJOINTS40HOWEVER,FURTHERRESEARCHESHAVEDEMONSTRATEDTHATTWOSTEPSCLINCHINGCANALSOIMPROVETHEMECHANICALSTRENGTHOFCLINCHEDJOINTSMADEONALUMINUMSHEETS41THISRESULTSFROMTHEINCREASEINNECKTHICKNESSANDUNDERCUT24SOFAR,ANYINVESTIGATIONHASBEENPERFORMEDTODETERMINETHEINFLUENCEOFARESHAPINGSTEPWHILEJOININGBYCLINCHINGMETALWITHCOMPOSITESHEETS,INTERMSOFMATERIALFLOW,DAMAGEOFTHECOMPOSITE,CHARACTERISTICDIMENSIONSANDSTRENGTHTHEPRESENTINVESTIGATIONANALYZESTWOSTEPSCLINCHINGBASEDONRESHAPINGDEFORMATIONTHATFOLLOWSMECHANICALCLINCHING,ASAMETHODTOIMPROVETHEMECHANICALBEHAVIOROFCLINCHEDCONNECTIONSPERFORMEDONHYBRIDMETALCOMPOSITESJOINTSINPARTICULAR,ALUMINUMALLOYSERIESAA6XXXANDCARBONFIBERREINFORCEDPOLYMERCFRPSHEETSWITHLONGFIBERSANDTHERMOSETTINGMATRIXWEREJOINEDBYCLINCHINGDIFFERENTTYPESOFRESHAPINGTOOLSANDVALUESOFJOININGFORCESWERETESTEDINORDERTODETERMINETHEOPTIMALPROCESSWINDOWMECHANICALTESTSBASEDONSINGLELAPSHEARTESTSWEREPERFORMEDTOCHARACTERIZETHEMECHANICALBEHAVIOROFTHEJOINTSANDTOVERIFYTHEEFFECTIVENESSOFTHERESHAPINGMETHODINADDITION,MORPHOLOGICALANALYSISWASCONDUCTEDTOUNDERSTANDHOWTHERESHAPINGSTEPINFLUENCESTHEMECHANICALBEHAVIOR,THEMAINJOINTSDIMENSIONSANDTHEDAMAGEONCFRPSHEET2MATERIALSANDMETHODS21MATERIALSROLLEDSHEETSOF30MMTHICKALUMINUMALLOYAA6024WEREUSEDINTHISSTUDYTHISISAPRECIPITATIONHARDENABLEALUMINUMALLOYWITHSIANDMGASTHEMAINALLOYINGELEMENTSTHECHEMICALCOMPOSITIONOFTHEALUMINUMWASDETERMINEDBYMEANSOFAXRAYFLUORESCENCESPECTROMETERTHEMAINCHEMICALELEMENTSOFTHEALLOYAREREPORTEDINTABLE1THEALUMINUMSHEETWASCOUPLEDWITHACFRPSHEETWITHATHICKNESSOF14MMTHECFRPLAMINATESWEREMANUFACTUREDUSINGPLAINWEAVESKCHEMICAL,UGN200THECARBONFIBERPREPREGSMRCPYROFILTM,TR30SANDATHERMOSETTINGEPOXYRESINBISPHENOLATYPEEPOXYPHENOLNOVOLACTYPEEPOXYWERECUREDFOR2HAT130CTHEINITIALTHICKNESSOFPREPREGFORAPLYWAS03MMBEFORETHEPRESSUREWASAPPLIEDTHEFINALRESINCONTENTWASESTIMATEDTOBEABOUT53,ASREPORTEDINTABLE2THEMECHANICALPROPERTIESANDFABRICATIONPROCEDUREOFTHECFRPSHEETAREREPORTEDIN39THEMAINCHARACTERISTICSANDMECHANICALPROPERTIESOFTHECFRPAREREPORTEDINTABLES2AND322CLINCHINGEQUIPMENTCLINCHEDTESTSWERECARRIEDOUTBYMEANSOFAPORTABLECLINCHINGMACHINEMODELPYTHONBYJURADOSRLRIVOTORTOPERUGIA,ITALYINTHISINVESTIGATION,THECLINCHINGCONFIGURATIONUSEDINTHEFIRSTSTEPWASKEPTUNCHANGEDINTHISSTEPMECHANICALCLINCHING,ASPLITDIEWITHTHREESECTORS,DIEANVILDEPTHH11MMANDINITIALDIAMETERD52MMWASUSED,ASSCHEMATICALLYDEPICTEDINFIG1ATHESPLITDIEWASPREFERREDTOFIXEDGROOVEDONEBECAUSEITGENERALLYPRODUCESLARGERUNDERCUTSWITHLOWERFORMINGFORCESANDITENABLESANEASIEREXTRACTIONOFCOMPOSITECRUMBLESFROMTHEDIECAVITY42THETOOLSETOFTHEFIRSTSTEPALSOINCLUDEDAPUNCHWITHTAPERANGLEOF6,DIAMETERD4MMANDFILLETRADIUSOF02MMAFTERPERFORMINGTHEFIRSTJOININGSTEP,THECLINCHINGTOOLSWERESUBSTITUTEDANDTHESECONDSTEPWASPERFORMEDINTHESECONDSTEPRESHAPING,THEHEIGHTOFTHEPUNCHWASVARIEDINORDERTOPRODUCEDIFFERENTPUNCHDIECAVITYGEOMETRIESRESHAPINGDEPTH,RDTHISWASDONEBYCHANGINGTHEHEIGHTHROFANADJUSTABLERING,ASDEPICTEDINFIG1BTHESTUDYALSOINVESTIGATEDTHEEFFECTOFTHETABLE1CHEMICALCOMPOSITIONOFALUMINUMALLOYELEMENTMGSIMNALCONCENTRATION0330960879662182FLAMBIASE,DCKO/COMPOSITESTRUCTURES1642017180188TABLE2MANUFACTURINGCONDITIONSOFCFRPTYPEOFWOVENFABRICTHICKNESSOFLAMINATEMMNUMBEROFPLIESFIBERVOLUMEFRACTIONLAYUPANGLEPLAINWEAVE3K1475330450TABLE3MECHANICALPROPERTIESOFCFRPANDAA6082T6ALLOYMATERIALELASTICMODULUSGPAYIELDSTRENGTH,R02MPAULTIMATETENSILESTRENGTHMPAFLOWSTRESSMPABEARINGSTRENGTHMPAILSSMPAAA602469282380RP459E0088CFRP17539627366191FIG1SCHEMATICOFTHEADOPTEDCLINCHINGTOOLSINAFIRSTSTEPANDBSECONDSTEPTABLE4EXPERIMENTALPLANCASERESHAPINGDEPTH,RDMMRESHAPINGFORCE,FJKNNONORESHAPEP20RD22205P28RD22288P20RD11205P28RD21288P20RD0505205P28RD0505288RESHAPINGFORCEINTHESECONDSTEP,WHICHWASVARIEDOVERTWOLEVELSFJ205KNANDFJ288KN,WHILETHEFORMINGFORCEINTHEFIRSTSTEPKEPTUNCHANGEDFJ288KNTHESEVALUESWERESELECTEDACCORDINGTOPRELIMINARYTESTRESULTSANDTHEMAXIMUMAVAILABLEFORCEOFTHECLINCHINGMACHINETHEEXPERIMENTALPLANISSUMMARIZEDINTABLE4INALLTHETESTS,THEALUMINUMWASPLACEDATTHEPUNCHSIDE23MECHANICALCHARACTERIZATIONOFTHEJOINTSTHEMECHANICALBEHAVIOROFTHEJOINTSWASASSESSEDBYMEANSOFSINGLELAPSHEARTESTSTOTHISEND,AUNIVERSALTESTMACHINEMODEL32231BYMTSWASUSEDUSING25KNFULLSCALEUNDERQUASISTATICCONDITIONSCONSTANTCROSSHEADSPEED1MM/MINTHEGEOMETRYANDSPECIMENDIMENSIONSAREREPORTEDINFIG2AFOREACHJOININGCONDITION,FIVEREPLICATESWEREPERFORMEDANDTHEAVERAGEANDSTANDARDDEVIATIONOFTHEULTIMATELAPSHEARFORCEFRMAXIMUMLOADRECORDEDDURINGTHESHEARTESTANDABSORBEDENERGYW,CALCULATEDASTHEAREAUNDERLYINGTHELOADDISPLACEMENTCURVEOFASHEARTEST,WEREDETERMINEDTOEXAMINETHEDEFORMATIONOFTHEJOINTANDCRACKPROPAGATIONTHROUGHOUTTHECFRPSHEETDURINGTHESINGLELAPSHEARTESTS,ADOUBLEHALVESJOINTSPECIMENTYPEIIWASADOPTED,ASSCHEMATIZEDINFIG2BTHISSPECIMENISCONSTITUTEDBYTWOHALVESJOINTSWHICHWERESECTIONEDAFTERJOININGBYCLINCHINGWHENPRODUCINGTHESESPECIMENSGREATCAREWASPAIDINORDERTOPRODUCETHECROSSSECTIONSPARALLELTOTHELOADINGDIRECTION,ANDTHELINELC1C2,WHICHPASSESBYTHEJOINTSCENTERSC1ANDC2,PERPENDICULARTOTHELOADINGDIRECTION,ASSCHEMATIZEDINFIG2BTHREEREPLICATIONSWEREPERFORMEDFORSPECIMENSTYPEIITOENSUREREPLICABILITYOFTHESETESTSTHISSHAPECONSTRAINEDTHEROTATIONOFTHESPECIMENAROUNDTHEJOINTDURINGTHESHEARTESTTHECROSSSECTIONEVOLUTIONDURINGTHESHEARTESTWASTHUSRECORDEDUSINGA16BITDSLCAMERAMODELFLAMBIASE,DCKO/COMPOSITESTRUCTURES1642017180188183FIG2SCHEMATICOFTHESPECIMENSUSEDFORCHARACTERIZATIONTESTSASINGLELAPSHEARTESTANDBTWOHALVES”SPECIMENUSEDFORANALYSISOFMATERIALFLOWOFCROSSSECTIOND5200BYNIKONWITHRESOLUTIONOF60004000MOUNTEDONASTEREOMICROSCOPEMODELSTEMIDV4BYZEISS24ANALYSISOFJOINTSMORPHOLOGYTOINVESTIGATETHEINFLUENCEOFTHEAFOREMENTIONEDPROCESSPARAMETERSANDPARTICULARLYTHEDIFFERENCEBETWEENCLINCHEDANDRESHAPEDJOINTS,THECROSSSECTIONSFORALLTHESPECIMENSWEREANALYZEDTHEJOINTSWERECUTINTHEMIDDLEBYMEANSOFALOWSPEEDSAWWITHDIAMONDBLADETHECROSSSECTIONSWERETHUSANALYZEDBYMEANSOFOPTICALMETALLOGRAPHICMICROSCOPEMODELDM5000BYLEICAMICROSYSTEMSANDTHEABOVEMENTIONEDSTEREOSCOPEUNDERREFLECTIVELIGHTFOREACHTOOLSET,THEMAINGEOMETRICALPARAMETERS,NAMELYTHEUNDERCUTTS,NECKTHICKNESSTN,ANDBULGEHEIGHTHDEPICTEDINFIG3,WEREMEASURED3RESULTSANDDISCUSSION31GEOMETRYOFTHEJOINTTHECROSSSECTIONSOFTHECLINCHEDJOINTSMADEBYSINGLESTEPCLINCHINGNORESHAPEANDTWOSTEPSCLINCHINGAREREPORTEDINFIG4THECROSSSECTIONSOFTHEJOINTSSHOWACERTAINASYMMETRYDIFFERENTUNDERCUTANDNECKTHICKNESSVALUESOFTHELEFTANDRIGHTHANDSIDESOFTHEJOINTSTHISISDUETOTHEHIGHSTIFFNESSANDANISOTROPYOFTHECFRPSHEETTHATDRIVESTHEALUMINUMMATERIALTOWARDSDIRECTIONSOFLESSRESISTANCEBETWEENFIBERPLIESTOTHISEND,FIVECROSSSECTIONSFOREACHPROCESSINGCONDITIONWEREANALYZEDASCANBEOBSERVEDFROMFIG4,NOCRACKAPPEARONTHEALUMINUMSHEETATTHENECKREGIONREGARDLESSTHEJOININGCONDITIONCOMPARINGTHECROSSSECTIONSOFTWOSTEPS”JOINTSWITHFIG3MAINGEOMETRICALCHARACTERISTICSOFALUMINUM/CFRPCLINCHEDJOINTSNORESHAPEONES,SOMEDIFFERENCESCANBEAPPRECIATEDINDEED,THECONTACTSURFACEOFALUMINUMCFRPSHOWNINFIG4AISRELATIVELYREGULAR,WHILE,ONTHEOTHERHAND,BYINCREASINGTHERESHAPINGDEPTHRDTHECONTACTSURFACEBECOMESMOREIRREGULARSHOWINGINTERMEDIATESIDEPROTRUSIONSASALSODEPICTEDINFIG5BINADDITION,EXCESSIVERESHAPINGDEPTHSPRODUCEDSMALLERCONTACTSURFACETHISWASPARTICULARLYEVIDENTINFIG4F,GANDHIGHERMAGNIFICATIONREPORTEDINFIG5CANDBULGEHEIGHTEGFORP28RD2JOINTSH16007MMTHISHASPOTENTIALDETRIMENTALEFFECTSOFTHEMECHANICALBEHAVIOROFTHECLINCHEDJOINTSASREPORTEDIN32INADDITION,WHENHISSMALLERTHANTHETHICKNESSOFTHECFRP,THELASTPLIESOFTHECFRPHOLEARENOTINCONTACTWITHTHEALUMINUMBULGEPROMOTINGTHEONSETOFDELAMINATIONANDCONSEQUENTREDUCTIONINLOADCAPACITYTHEMECHANICALBEHAVIOROFCLINCHEDJOINTSISDETERMINEDBYSEVERALFACTORSINCLUDINGTHEGEOMETRYOFTHEJOINTS,THELENGTHOF184FLAMBIASE,DCKO/COMPOSITESTRUCTURES1642017180188FIG4CROSSSECTIONSOFTHEJOINTSPRODUCEDUNDERDIFFERENTPROCESSINGCONDITIONSFIG5EFFECTOFRESHAPINGONTHECONTACTBETWEENTHEALUMINUMBULGEANDCFRPHOLEBYRESHAPINGTHEAREASREFERTOSELECTIONSDEPICTEDINFIG4FLAMBIASE,DCKO/COMPOSITESTRUCTURES1642017180188185CONTACTARC,THEBULGEHEIGHT,NECKTHICKNESSANDUNDERCUTDIMENSIONS20,THEDAMAGETHATMAYDEVELOPDURINGTHEJOINTFORMATION36ANDSTRAINHARDENINGSINCETHEPROCESSISGENERALLYCARRIEDOUTATROOMTEMPERATUREASWELLASTHEDAMAGEOFTHECFRPNEARTHEHOLETOUNDERSTANDTHEINFLUENCEOFTHERESHAPINGTOOLSONTHEMECHANICALBEHAVIOROFTHEJOINTS,THECHARACTERISTICDIMENSIONS,NAMELYTHEUNDERCUTTS,NECKTHICKNESSTNWERECOMPAREDINFIG6COMPARINGTHECRITICALJOINTDIMENSIONS,ITISEVIDENTTHATTHEUNDERCUT,WHICHISMUCHSMALLERTHANTHENECKTHICKNESS,REPRESENTSTHEKEYPARAMETERTHATDETERMINESTHEMECHANICALBEHAVIOROFTHEJOINTSTHERESHAPINGFORCEISMAINLYEXERTEDONTHEALUMINUMSIDEWALLSOFTHEJOINTDEPENDINGONTHERESHAPINGVALUERD,THISMAYRESULTINDIFFERENTMATERIALFLOWSWHENSMALLVALUESOFRDAREADOPTED,THERESHAPINGSTEPPRODUCESANINCREASEINTHEUNDERCUTANDHIGHERCONTACTPRESSUREBETWEENTHEALUMINUMANDCFRPASALSOSHOWNINTHEMACROGRAPHDEPICTEDINFIG5WHENLARGEVALUESOFRDAREUSED,THEBULGEHEIGHTHREDUCESSINCETHEDIEPUSHESTHEALUMINUMBULGETOWARDSTHEJOINTAXISRATHERTHANEXPANDINGTHEUNDERCUT,ASSHOWNINFIG5CFIG6VARIATIONOFTHENECKTHICKNESSANDUNDERCUTBYADOPTINGDIFFERENTRESHAPINGTOOLSANDJOININGFORCES32MATERIALFLOWDURINGTHERESHAPINGSTEP,THEALUMINUMSIDEWALLISPARTIALLYINCONTACTWITHTHEPUNCHGUIDEDALUMINUMASSHOWNINFIG7,WHILETHEBOTTOMPARTOFTHEALUMINUMBULGEISLESSCONSTRAINEDFREEALUMINUMWHENLOWVALUESOFRDAREADOPTEDEGRD05MM,THEFREEALUMINUMREGIONISCHARACTERIZEDBYAREDUCEDHEIGHTTHUS,THISREGIONISMAINLYSUBJECTEDTOUPSETTINGTHATPROMOTESANINCREASEINTHEUNDERCUTANDCONTACTPRESSUREBETWEENTHEALUMINUMANDTHESURROUNDINGCFRP,ASSCHEMATIZEDINFIG7AONTHEOTHERHAND,WHENLARGERVALUESOFRDAREUSEDEGRD10MMANDRD20MMADIFFERENTMATERIALFLOWISPRODUCEDINDEED,UNDERSUCHCONDITIONS,THEGREATERHEIGHTOFTHEFREEALUMINUMREGIONINVOLVESALOWERSTIFFNESSTHUS,AHIGHERINSTABILITYISPRODUCEDTHATPROMOTESANINWARDBENDINGOFTHEALUMINUMBULGE,WHICHRESULTSINREDUCTIONOFTHEUNDERCUTTSANDTHEBULGEHEIGHTHTHEMATERIALFLOWPRODUCEDUNDERSUCHCONDITIONSISSCHEMATIZEDINFIG7BWHENTHEHIGHERLEVELSOFRESHAPINGFORCEWEREUSED,THEMATERIALFLOWISACCENTUATEDTHEN,ITRESULTEDINHIGHERINCREASEINTHEUNDERCUTWHENRD05MMANDAHIGHERREDUCTIONINTHEUNDERCUTFORRD10AND20MM33MECHANICALBEHAVIOROFTHEJOINTSLOADDISPLACEMENTCURVESOFCLINCHEDJOINTSMADEBYDIFFERENTTOOLSAREREPORTEDINFIG8ALLTHEJOINTSFAILEDBYPULLOUT,WHICHISATYPICALFAILUREMODEOFCLINCHEDCONNECTIONSCHARACTERIZEDBYRELATIVELYSMALLUNDERCUTSTHECURVESREPORTEDINFIG8SHAREACOMMONBEHAVIORESPECIALLYINTHEFIRSTPATH,WHICHSUGGESTSTHATTHESTIFFNESSOFTHEJOINTISNEGLIGIBLYINFLUENCEDBYTHERESHAPINGSTEPONTHEOTHERHAND,THEJOINTSARECHARACTERIZEDBYDIFFERENTVALUESOFSHEARSTRENGTHANDABSORBEDENERGY,WHICHDEMONSTRATESTHATTHERESHAPINGSTEPCANBEPOSITIVELYEMPLOYEDTOIMPROVETHEMECHANICALBEHAVIOROFCLINCHEDJOINTSBECAUSEOFTHEPULLOUTFAILUREMODE,LOADDISPLACEMENTCURVESSHOWSAGRADUALLOADREDUCTIONAFTERREACHINGTHEPEAKLOADSHEARSTRENGTHOFTHEJOINTUPTOTHECOMPLETELOSSOFTHECARRYINGLOADCAPABILITYTHISBEHAVIORISCOMMONLYPREFERABLEASCOMPAREDTOSTEEPERLOADREDUCTIONTRENDSBRITTLEBEHAVIOROFTHEJOINTASITENABLESMOREENERGYFIG7SCHEMATICOFMATERIALFLOWUSINGASMALLVALUEOFRDANDBLARGEVA
- 温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。
川公网安备: 51019002004831号