ASTM D 6264-1998(3)

Standard Test Method for Measuring Damage Resistance of Fiber-Reinforced Polymer-Matrix Composite to Concentrated Quasi-Static Indentation Force

6.7.1TheQSItestprimarilyhasbeenusedfortestingcarbon- ber-reinforcedtapeandfabriclaminateswithpolymermatrices.Forothermaterials,aquitedifferentresponsemayoccur.

6.7.2Nonlaminated,3D ber-reinforced,ortextilecompos-itesmayfailbydifferentmechanismsthanlaminates.Themostcriticaldamagemaybeintheformofmatrixcrackingor berfailure,orboth,ratherthandelaminations.7.Apparatus

7.1TestingMachine—ThetestingmachineshallbeinconformancewithPracticesE4andshallsatisfythefollowingrequirements:

7.1.1TestingMachineHeads—Thetestingmachineshallhavebothanessentiallystationaryheadandamovablehead.7.1.2DriveMechanism—Thetestingmachinedrivemecha-nismshallbecapableofimpartingtothemovableheadacontrolledvelocitywithrespecttothestationaryhead.Thevelocityofthemovableheadshallbecapableofbeingregulatedasspeci edin11.6.

7.1.3LoadIndicator—Thetestingmachineload-sensingdeviceshallbecapableofindicatingthetotalloadbeingcarriedbythetestspecimen.Thisdeviceessentiallyshallbefreefrominertialagatthespeci edrateoftestingandshallindicatetheloadwithanaccuracyovertheloadrange(s)ofinterestofwithin61%oftheindicatedvalue.

7.1.4Grips—Thetopheadofthetestingmachineshallcarryagriptoholdtheindentersuchthatthedirectionofloadappliedtothespecimeniscoincidentwiththeaxisoftravel.Thegripshallapplysufficientpressuretopreventslippageoftheindenter.Thelowerheadshallhaveameansofattachinga atrigidsupport.

7.2FlatRigidSupport—A atrigidsurfaceshallbeat-tachedtothelowerheadandusedtosupportthespecimenortest xture.Thesupportsurfaceshallbenormaltotheaxisoftravelofthetestingmachineheadandhavealargeenoughsurfacetosupportcompletelythespecimenortest xture.Aconvenientmeansofprovidingthissurfaceisthroughtheuseofametal“T”inwhichthelowerpartofthe“T”isclampedinthelowergripsandthetoppartofthe“T”providesthesupportsurface.Iftherigidlybackedcon gurationistobeused,thissupportshallbemadefromsteelwithaminimumthicknessof12.7mm(0.5in.).

7.3Indenter—Theindentershallhaveasmoothhemispheri-caltipwithadiameterof12.760.1mm(0.50060.003in.)andahardnessof60to62HRCasspeci edinTestMethodsE18.Ifadifferentindenterisusedaspartofthetesting,theshapeanddimensionsshallbenoted.

7.4IndenterDisplacementIndicator—Theaxialdisplace-mentoftheindenterrelativetothesupport xturemaybeestimatedasthecrossheadtravel,providedthedeformationofthetestingmachineandsupport xtureislessthan2%ofthecrossheadtravel.Ifnot,theindenterdisplacementshallbeobtainedfromaproperlycalibratedexternalgageortransducerlocatedbetweentheindenterandthesupport xtureortherigidsupportsurface.Thedisplacementindicatorshallindicatethedisplacementwithanaccuracyof61%ofthethicknessofthespecimen.

7.5LoadVersusIndenterDisplacement(FVersusd)Record—AnX-Yplotter,orsimilardevice,shallbeusedtomakeapermanentrecordduringthetestofloadversusindenterdisplacement.Alternatively,thedatamaybestoreddigitallyandpostprocessed.

7.6SpecimenSupport—Thedamageresistancemaybedeterminedforaspecimenthatissimplysupportedorrigidlybacked.Forbothcon gurations,thespecimen’sfaceshallbeheldnormaltotheaxisoftheindenter.

7.6.1SimplySupportedCon guration—The xtureshallconsistofasingleplatewitha127.062.5mm(5.0060.10in.)diameteropeningmadefromastructuralmetalsuchasaluminumorsteel.Thetoprimoftheopeningshallberoundedwitharadiusof0.7560.25mm(0.0360.01in.).Theplateshallbesufficientlylargetosupporttheentirelowersurfaceofthespecimen,excludingthecircularopening.Thethicknessoftheplateshallbeaminimumof25mm(1.0in.)andgreaterthantheexpectedmaximumindenterdisplacement.Atypicalsupport xtureisshowninFig.2.

7.6.2RigidlyBackedCon guration—Thespecimenshallbeplaceddirectlyonthe atrigidsupportthatismountedinthelowerheadofthetestingmachine.Forthiscon guration,thesupportshallbemadefromsteelwithaminimumthicknessof12.7mm(0.5in.).

7.7Micrometers—Themicrometer(s)shalluseasuitablesizediameterball-interfaceonirregularsurfacessuchasthebag-sideofalaminate,anda atanvilinterfaceonmachinedorverysmoothtooledsurfaces.Theaccuracyoftheinstru-mentsshallbesuitableforreadingtowithin1%ofthesamplewidthandthickness.Fortypicalspecimengeometries,aninstrumentwithanaccuracyof62.5µm[60.0001in.]isdesirableforthicknessmeasurement,whileaninstrumentwithanaccuracyof625µm[60.001in.]isdesirableforwidthmeasurement.

7.8DentDepthIndicator—Thedentdepthcanbemeasuredusingadialdepthgage,adepthgagemicrometer,oraproperlycalibrateddisplacementtransducer.Themeasuringprobeshallhaveahemisphericaltipwithadiameterbetween1.5and5.0mm(0.06-0.20in.).Aninstrumentwithanaccuracyof625µm[60.001in.]isdesirablefordepthmeasurement.

8.SamplingandTestSpecimens

8.1Sampling—Testatleast vespecimenspercondition,unlessvalidresultscanbegainedthroughtheuseoffewerspecimens,suchasinthecaseofadesignedexperiment.Forstatisticallysigni cantdata,theproceduresoutlinedinPracticeE122shouldbeconsulted.Reportthemethodofsampling.8.2SpecimenLay-Up—Thelaminateshallbe atandhaveacrosssectionofconstantthickness.

8.2.1Forcomparisonscreeningofthedamageresistanceofdifferentmaterials,thefollowinglaminateissuggested.Aquasi-isotropiclay-upwithaspecimenthicknessintherangeof3.5to5.0mm(0.14to0.20in.)withatargetthicknessof4.2mm(0.17in.)shallbeobtainedasfollows:

8.2.1.1Tape—Laminateconstructionshallconsistoftheappropriatenumberofunidirectionalpliestoachieveatotalcuredthicknessnearestto4.2mm(0.17in.)withastackingsequenceof[45/0/ 45/90]NSwhereNisawholenumber.Ifthe“nearest”thicknessislessthan3.5mm(0.14in.),the

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