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1、Designation:D7249D7249M?121StardTestMethodfFacingPropertiesofSwichConstructionsbyLongBeamFlexure1ThisstardisissuedunderthefixeddesignationD7249D7249Mthenumberimmediatelyfollowingthedesignationindicatestheyearofiginaladop

2、tioninthecaseofrevisiontheyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperepsilon()indicatesaneditialchangesincethelastrevisionreapproval.ε1NOTE—Figure6wascrectededitiallyinMarch2014.1.Scope

3、1.1Thistestmethodcoversdeterminationoffacingpropertiesofflatswichconstructionssubjectedtoflexureinsuchamannerthattheappliedmomentsproducecurvatureoftheswichfacingplanesresultincompressivetensilefcesinthefacings.Permissib

4、lecematerialfmsincludethosewithcontinuousbondingsurfaces(suchasbalsawoodfoams)aswellasthosewithdiscontinuousbondingsurfaces(suchashoneycomb).1.2ThevaluesstatedineitherSIunitsinchpoundunitsaretoberegardedseparatelyasstard

5、.Thevaluesstatedineachsystemmaynotbeexactequivalentstherefeeachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnonconfmancewiththestard.1.2.1Withinthetexttheinchpoundunitsareshowninbra

6、ckets.1.3Thisstarddoesnotpurpttoaddressallofthesafetyconcernsifanyassociatedwithitsuse.Itistheresponsibilityoftheuserofthisstardtoestablishappropriatesafetyhealthpracticesdeterminetheapplicabilityofregulatylimitationspri

7、touse.NOTE1—AlternateproceduresfdeterminingthecompressivestrengthofunidirectionalpolymermatrixcompositesmaterialsinaswichbeamconfigurationmaybefoundinTestMethodD5467D5467M.2.ReferencedDocuments2.1ASTMStards:2C274Terminol

8、ogyofStructuralSwichConstructionsC393TestMethodfFlexuralPropertiesofSwichConstructionsD3878TerminologyfCompositeMaterialsD5229D5229MTestMethodfMoistureAbsptionPropertiesEquilibriumConditioningofPolymerMatrixCompositeMate

9、rialsD5467D5467MTestMethodfCompressivePropertiesofUnidirectionalPolymerMatrixCompositeMaterialsUsingaSwichBeamD7250D7250MPracticefDeterminingSwichBeamFlexuralShearStiffnessE6TerminologyRelatingtoMethodsofMechanicalTestin

10、gE122PracticefCalculatingSampleSizetoEstimateWithSpecifiedPrecisiontheAveragefaacteristicofaLotProcessE177PracticefUseoftheTermsPrecisionBiasinASTMTestMethodsE251TestMethodsfPerfmanceacteristicsofMetallicBondedResistance

11、StrainGagesE456TerminologyRelatingtoQualityStatisticsE1309GuidefIdentificationofFiberReinfcedPolymerMatrixCompositeMaterialsinDatabasesE1434GuidefRecdingMechanicalTestDataofFiberReinfcedCompositeMaterialsinDatabases3.Ter

12、minology3.1Definitions—TerminologyD3878definestermsrelatingtohighmodulusfiberstheircomposites.TerminologyC274definestermsrelatingtostructuralswichconstructions.TerminologyC393definestermsrelatingtoplastics.TerminologyE6d

13、efinestermsrelatingtomechanicaltesting.TerminologyE456PracticeE177definetermsrelatingtostatistics.IntheeventofaconflictbetweentermsTerminologyD3878shallhaveprecedenceovertheotherterminologies.3.2Symbols:b=specimenwidthc=

14、cethicknessCV=coefficientofvariationstatisticofasamplepopulationfagivenproperty(inpercent)d=swichtotalthickness1ThistestmethodisunderthejurisdictionofASTMCommitteeD30onCompositeMaterialsisthedirectresponsibilityofSubcomm

15、itteeD30.09onSwichConstruction.CurrenteditionapprovedAug.12012.PublishedDecember2012.iginallyapprovedin2006.Lastpreviouseditionapprovedin2006asD7249D7249M–06.DOI:10.1520D7249_D7249M12.2FreferencedASTMstardsvisittheASTMwe

16、bsitewww.astm.gcontactASTMCustomerServiceat.FAnnualBookofASTMStardsvolumeinfmationrefertothestard’sDocumentSummarypageontheASTMwebsite.Copyright?ASTMInternational100BarrHarbDrivePOBoxC700WestConshohockenPA194282959.Unite

17、dStates1instrument(s)shallhaveanaccuracyof625m[60.001in.]fthicknessmeasurementanaccuracyof6250m[60.010in.]flengthwidthmeasurement.NOTE4—Theaccuraciesgivenabovearebasedonachievingmeasurementsthatarewithin1%ofthesampleleng

18、thwidththickness.7.2LoadingFixtures7.2.1StardConfiguration—Thestardloadingfixtureshallconsistofa4pointloadingconfigurationwithtwosupptbarsthatspanthespecimenwidthlocatedbelowthespecimentwoloadingbarsthatspanthespecimenwi

19、dthlocatedonthetopofthespecimen(Fig.1)Thefceshallbeappliedverticallythroughtheloadingbarswiththesupptbarsfixedinplaceinthetestmachine.Thestardloadingfixtureshallhavethecenterlinesofthesupptbarsseparatedbyadistanceof560mm

20、[22.0in.]thecenterlinesoftheloadingbarsseparatedbyadistanceof100mm[4.0in.].7.2.2NonStardConfigurations—Allotherloadingfixtureconfigurations(seeFig.2)areconsiderednonstarddetailsofthefixturegeometryshallbedocumentedinthet

21、estrept.Figs.35showtypicaltestfixtures.Nonstard34pointloadingconfigurationshavebeenretainedwithinthisstarda)fhisticalcontinuitywithpreviousversionsofTestMethodC393b)becausesomeswichpaneldesignsrequiretheuseofnonstardload

22、ingconfigurationstoachievefacesheetfailuremodesc)loaddeflectiondatafromnonstardconfigurationsmaybeusedwithStardPracticeD7250D7250Mtoobtainswichbeamflexuralshearstiffnesses.7.2.3SupptLoadingBars—Thebarsshallbedesignedtoal

23、lowfreerotationofthespecimenattheloadingsupptpoints.Thebarsshallhavesufficientstiffnesstoavoidsignificantdeflectionofthebarsunderloadanyobviousbowingofthebarsanygapsoccurringbetweenthebarsthetestspecimenduringloadingshal

24、lbeconsideredsignificantdeflection.Therecommendedconfigurationhasa25mm[1.0in.]wideflatsteelloadingblocktocontactthespecimen(throughrubberpressurepads)isloadedviaeitheracylindricalpivot(seeFig.3)aVshapedbarridinginaVgroov

25、einthetopoftheflatbottomedsteelloadingpad.ThetipsoftheVshapedloadingbarsshallhaveaminimumradiusof3mm[0.12in.].TheVgrooveintheloadingpadshallhavearadiuslargerthantheloadingbartiptheangularopeningofthegrooveshallbesuchthat

26、thesidesoftheloadingbarsdonotcontactthesidesoftheVgrooveduringthetest.Loadingbarsconsistingof25mm[1.0in.]diametersteelcylindersmayalsobeusedbutthereisagreaterriskoflocalspecimencrushingwithcylindricalbars.Alsotheloadsupp

27、tspanlengthstendtoincreaseasthespecimendeflectswhencylindricalloadingbarswithoutVgroovedloadingpadsareused(e.g.rollingsuppts).7.2.4PressurePads—RubberpressurepadshavingaSheAdurometerof60awidthof25mm[1.0in.]anominalthickn

28、essof3mm[0.125in.]spanningthefullwidthofthespecimenshallbeusedbetweentheloadingbarsspecimentopreventlocaldamagetothefacings.7.3TestingMachine—ThetestingmachineshallbeinaccdancewithPracticesE4shallsatisfythefollowingrequi

29、rements:7.3.1TestingMachineConfiguration—Thetestingmachineshallhavebothanessentiallystationaryheadamovablehead.7.3.2DriveMechanism—Thetestingmachinedrivemechanismshallbecapableofimpartingtothemovableheadacontrolledveloci

30、tywithrespecttothestationaryhead.Thevelocityofthemovableheadshallbecapableofbeingregulatedinaccdancewith11.4.7.3.3FceIndicat—ThetestingmachinefcesensingdeviceshallbecapableofindicatingthetotalfcebeingFIG.1TestSpecimenFix

31、tureConfigurationSupptSpan(S)LoadSpan(L)Stard4Point560mm[22.0in.]100mm[4.0in.]NonStard3Point(span)S0.04Point(QuarterSpan)SS24Point(ThirdSpan)SS3FIG.2LoadingConfigurationsFIG.3Stard4PointLoadingConfigurationD7249D7249M?12

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