Designation:E2661/E2661M−15StandardPracticeforAcousticEmissionExaminationofPlate-likeandFlatPanelCompositeStructuresUsedinAerospaceApplications1ThisstandardisissuedunderthefixeddesignationE2661/E2661M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope*1.1Thispracticecoversacousticemission(AE)examina-tionormonitoringofpanelandplate-likecompositestructuresmadeentirelyoffiber/polymercomposites.1.2TheAEexaminationdetectsemissionsourcesandlocatestheregion(s)withinthecompositestructurewheretheemissionoriginated.WhenproperlydevelopedAE-basedcri-teriaforthecompositeitemareinplace,theAEdatacanbeusedfornondestructiveexamination(NDE),characterizationofprooftesting,documentationofqualitycontrolorfordecisionsrelativetostructural-testterminationpriortocomple-tionofaplannedtest.OtherNDEmethodsmaybeusedtoprovideadditionalinformationaboutlocateddamageregions.ForadditionalinformationseeX1.1inAppendixX1.1.3Thispracticecanbeappliedtoaerospacecompositepanelsandplate-likeelementsasapartofincominginspection,duringmanufacturing,afterassembly,continuously(duringstructuralhealthmonitoring)andatperiodicintervalsduringthelifeofastructure.1.4Thispracticeismeantforfiberorientationsthatincludecross-plies,angle-plylaminatesortwo-dimensionalwovenfabrics.Thispracticealsoappliesto3-Dreinforcement(forexample,stitched,z-pinned)whenthefibercontentinthethirddirectionislessthan5%(basedonthewholecomposite).1.5Thispracticeisdirectedtowardcompositematerialsthattypicallycontaincontinuoushighmodulusgreaterthan20GPa[3Msi]fibers.1.6ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.1.7This...
