Designation:D7248/D7248M−12StandardTestMethodforBearing/BypassInteractionResponseofPolymerMatrixCompositeLaminatesUsing2-FastenerSpecimens1ThisstandardisissuedunderthefixeddesignationD7248/D7248M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethoddeterminestheuniaxialbearing/bypassinteractionresponseofmulti-directionalpolymermatrixcom-positelaminatesreinforcedbyhigh-modulusfibersbyeitherdouble-sheartensileloading(ProceduresAandC)orsingle-sheartensileorcompressiveloading(ProcedureB)ofatwo-fastenerspecimen.Thescopeofthistestmethodislimitedtonetsection(bypass)failuremodes.Standardspecimenconfigurationsusingfixedvaluesoftestparametersarede-scribedforeachprocedure.Anumberoftestparametersmaybevariedwithinthescopeofthestandard,providedthattheparametersarefullydocumentedinthetestreport.Thecompositematerialformsarelimitedtocontinuous-fiberordiscontinuous-fiber(tapeorfabric,orboth)reinforcedcom-positesforwhichthelaminateisbalancedandsymmetricwithrespecttothetestdirection.Therangeofacceptabletestlaminatesandthicknessesaredescribedin8.2.1.1.2ThistestmethodisconsistentwiththerecommendationsofMIL-HDBK-17,whichdescribesthedesirableattributesofabearing/bypassinteractionresponsetestmethod.1.3Thetwo-fastenertestconfigurationsdescribedinthistestmethodaresimilartothoseinTestMethodD5961/D5961Maswellasthoseusedbyindustrytoinvestigatethebearingportionofthebearing/bypassinteractionresponseforboltedjoints,wherethespecimenmayproduceeitherabearingfailuremodeorabypassfailuremode.Shouldthetestspecimenfailinabearingfailuremoderatherthanthedesiredbypassmode,thenthetestshouldbeconsideredtobeabearingdominatedbearing/bypasstest,andthedatareductionandreportingproceduresofTestMethodD5961/D5961Mshouldbeusedinsteadofthosegiveninthisstandard.1.4ThevaluesstatedineitherSIunits...
