ASTM-C393-C393M-2006

Designation:C393/C393M–06StandardTestMethodforCoreShearPropertiesofSandwichConstructionsbyBeamFlexure1ThisstandardisissuedunderthefixeddesignationC393/C393M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.1.Scope1.1Thistestmethodcoversdeterminationofthecoreshearpropertiesofflatsandwichconstructionssubjectedtoflexureinsuchamannerthattheappliedmomentsproducecurvatureofthesandwichfacingplanes.Permissiblecorematerialformsincludethosewithcontinuousbondingsurfaces(suchasbalsawoodandfoams)aswellasthosewithdiscontinuousbondingsurfaces(suchashoneycomb).1.2ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Withinthetexttheinch-poundunitsareshowninbrackets.Thevaluesstatedineachsystemarenotexactequivalents;therefore,eachsystemmustbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnonconformancewiththestandard.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2C273TestMethodforShearPropertiesofSandwichCoreMaterialsC274TerminologyofStructuralSandwichConstructionsD883TerminologyRelatingtoPlasticsD3878TerminologyforCompositeMaterialsD5229/D5229MTestMethodforMoistureAbsorptionPropertiesandEquilibriumConditioningofPolymerMa-trixCompositeMaterialsD7249/D7249MTestMethodforFacingPropertiesofSandwichConstructionsbyLongBeamFlexureD7250/D7250MPracticeforDeterminingSandwichBeamFlexuralandShearStiffnessE4PracticesforForceVerificationofTestingMachinesE6TerminologyRelatingtoMethodsofMechanicalTest-ingE122PracticeforCalculatingSampleSizetoEstimate,WithaSpecifiedTolerableError,theAverageforaCharacteristicofaLotorProcessE177PracticeforUseoftheTermsPrecisionandBiasinASTMTestMethodsE456TerminologyRelatingtoQualityandStatisticsE1309GuideforIdentificationofFiber-ReinforcedPolymer-MatrixCompositeMaterialsinDatabasesE1434GuideforRecordingMechanicalTestDataofFiber-ReinforcedCompositeMaterialsinDatabases3.Terminology3.1Definitions—TerminologyD3878definestermsrelatingtohigh-modulusfibersandtheircomposites.TerminologyC274definestermsrelatingtostructuralsandwichconstruc-tions.TerminologyD883definestermsrelatingtoplastics.TerminologyE6definestermsrelatingtomechanicaltesting.TerminologyE456andPracticeE177definetermsrelatingtostatistics.Intheeventofaconflictbetweenterms,TerminologyD3878shallhaveprecedenceovertheotherterminologies.3.2Symbols:b=specimenwidthc=corethicknessCV=coefficientofvariationstatisticofasamplepopulationforagivenproperty(inpercent)d=sandwichtotalthicknessDF,nom=effectivesandwichflexuralstiffnessEf=effectivefacingchordmoduluse=measuringstraininfacingFu=facingultimatestrength(tensileorcompressive)Fc=corecompressionallowablestrengthFs=coreshearallowablestrengthFsult=coreshearultimatestrengthFsyield=coreshearyieldstrengthk=coreshearstrengthfactortoensurecorefailureL=lengthofloadingspan1ThistestmethodisunderthejurisdictionofASTMCommitteeD30onCompositeMaterialsandisthedirectresponsibilityofSubcommitteeD30.09onSandwichConstruction.CurrenteditionapprovedSept.1,2006.PublishedOctober2006.Originallyapprovedin1957.Lastpreviouseditionapprovedin2000asC393–00.2ForreferencedASTMstandards,visittheASTMwebsite,@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.1Copyright(C)ASTMInternational.100BarrHarbourDriveP.O.boxC-700WestConshohocken,Pennsylvania19428-2959,UnitedStatesCopyrightbyASTMInt'l(allrightsreserved);TueNov322:00:23EST2009Downloaded/printedbySGSNorthAmericaInc.pursuanttoLicenseAgreement.Nofurtherreproductionsauthorized.S=lengthofsupportspanlpad=lengthofloadingpadn=numberofspecimensP=appliedforcePmax=maximumforcecarriedbytestspecimenbeforefailureFZftu=ultimateflatwisetensilestrengthPmax=maximumforcecarriedbytestspecimenbeforefailureSn-1=standarddeviationstatisticofasamplepopulationforagivenpropertys=facingstressorstrengtht=facingthicknessx1=testresultforanindividualspecimenfromthesamplepopulationforagivenpropertyx=meanoraverage(estimateofmean)ofasamplepopu-lationforagivenproperty4.SummaryofTestMethod4.1Thistestmethodconsistsofsubjectingabeamofsandwichconstructiontoabendingmomentnormaltotheplaneofthesandwich.Forceversusdeflectionmeasurementsarerecorded.4.2Theonlyacceptablefailuremodesarecoreshearorcore-to-facingbond.Failureofthesandwichfacingprecedingfailureofthecoreorcore-to-facingbondisnotanacceptablefailuremode.UseTestMethodD7249todeterminefacingstrength.5.SignificanceandUse5.1Flexuretestsonflatsandwichconstructionmaybeconductedtodeterminethesandwichflexuralstiffness,thecoreshearstrengthandshearmodulu