Designation:D7766/D7766M−11StandardPracticeforDamageResistanceTestingofSandwichConstructions1ThisstandardisissuedunderthefixeddesignationD7766/D7766M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticeprovidesinstructionsformodifyinglami-natequasi-staticindentationanddrop-weightimpacttestmeth-odstodeterminedamageresistancepropertiesofsandwichconstructions.Permissiblecorematerialformsincludethosewithcontinuousbondingsurfaces(suchasbalsawoodandfoams)aswellasthosewithdiscontinuousbondingsurfaces(suchashoneycomb,trusscoresandfiber-reinforcedcores).1.2ThispracticesupplementsTestMethodsD6264/D6264M(forquasi-staticindentationtesting)andD7136/D7136M(fordrop-weightimpacttesting)withprovisionsfortestingsandwichspecimens.Severalimportanttestspecimenparameters(forexample,facingthickness,corethicknessandcoredensity)arenotmandatedbythispractice;however,repeatableresultsrequirethattheseparametersbespecifiedandreported.1.3Threetestproceduresareprovided.ProceduresAandBcorrespondtoD6264/D6264Mtestproceduresforrigidly-backedandedge-supportedtestconditions,respectively.Pro-cedureCcorrespondstoD7136/D7136Mtestprocedures.Allthreeproceduresaresuitableforimpartingdamagetoasandwichspecimeninpreparationforsubsequentdamagetolerancetesting.1.4Ingeneral,ProcedureAisconsideredtobethemostsuitableprocedureforcomparativedamageresistanceassessments,duetoreducedinfluenceofflexuralstiffnessandsupportfixturecharacteristicsupondamageformation.However,theselectionofatestprocedureandassociatedsupportconditionsshouldbedoneinconsiderationoftheintendedstructuralapplication,andassuchProceduresBandCmaybemoreappropriateforcomparativepurposesforsomeapplications.1.5ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemarenotexacte...
