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17thWorldConferenceonNondestructiveTesting,25-28Oct2008,Shanghai,ChinatheNDTStudyofMetalCompositeMaterialTubeJunmingLIN1,JilinREN2,LuBAI21.Eddysun(Xiamen)ElectronicCo.,Ltd.,Xiamen361001,ChinaWeb:，，，，theKeyLaboratoryofNondestructiveTesting,MinistryofEducation，，，，NanchangJiangxi,330063,ChinaE-mail:jlren@tom.comWeb:，ETandthespecial-purposesensorsareusedtocarryoutthetestingoftheparentmetalandthecompoundlayer.Accordingtopracticaltesting,theconclusioncanbeobtainedthatthiskindofintegrationmethodisadvantageousfortesting,whichisprovidedwithaccurateresults,clearsignalsandconvenientoperationetc..Keywords:ultrasonictechnology,eddycurrenttesting,compositematerialtube,special-purposesensors1.SummaryAtpresent,interiorly,compositematerialsaremainlyusedinaviationandspaceflight,automobileindustry,chemicalindustry,textileindustry,machinemanufactureandiatrologyfield.Itiscloselylinkedwithpeople’slives.Therefore,testingofcompositematerialsisveryimportant.Butiftestingwithasingletestingmethod,theaimoftestingthewholecompositematerial(includingsurfaceandcompoundlayer)cannotbeachieved.Thusinstrumentsintegratedwithmulti-testingtoolsareneededtocarryouttesting.2.CompositematerialCompositematerialisakindofcombinationmaterialwhichadoptingonekindofmaterialasmatrix，andtheotherkindofmaterialasreinforcement.Differentmaterialscanlearnfromother’sadvantageousperformanceandoffsetone’sdisadvantageousaspects,socooperationeffectcanbeachieved,whichmakesthesyntheticalperformanceofcompositematerialbetterthantheoriginalmaterials.Thuscompositematerialcanmeetallkindsofdemands.Itsmatrixisdividedintotwokinds,includingmetalandnon-metal.Theoften-usedmetalmatrixincludesaluminium,magnesium,copper,titaniumortheiralloy.Nonmetalmatrixmainlyincludessyntheticresin,rubber,porcelain,graphiteandcarbonetc.Thereinforcementmaterialmainlyincludesfiberglass,fibercarbon,fiberboron,aramidfiberreinforcedplastic,fibercarborundum,fiberasbestus,crystalbeard,tinselandhardgranule.Compositematerialsaremainlyappliedinthefollowingdomains.Firstly,it’susedinaviationandspaceflightfield.Onaccountofgoodheatstabilityandhighspecificstrengthandspecificstiffnessofcompositematerial,itcanbeusedtofabricatewingsandfrontframesofairplanes,antennasupportconfiguration,solarbatterywingandcrust,crustofhugecarrierrocket,crustofengineandconfigurationcomponentofspaceshuttlesetc..Secondly,it’susedinautomobileindustry.Sincecompositematerialsisprovidedwithspeciallibrationdampcharacteristic,itcandecreaseliberationandnoiseandhasgoodanti-fatiguecapability.It’seasytofixafterdamageandconvenientforintegralfiguration.Thusitcanbeusedinthefabricationofautomobilebodywork,stressedcomponents,transmissionshaft,enginerackanditsinteriorcomponents.Thirdly,it’susedinchemicalindustry,textileindustry,machiningmanufacturefields.Materialscompoundedwithfibercarbonandcolophonyareprovidedwithgoodcorrosionresistingproperty.Soitcanbeusedinfabricationofchemicalindustrialequipment,textilemachines,papermachines,copycat,highspeedmachinetoolandexactitudeapparatusetc..Fourthly,it’susediniatrology.Fibercarboncompositematerialisprovidedwithexcellentmechanicsperformanceandspecialcharacteristicofnon-absorbabilityofXray,soitcanbeusedtofabricatemedicalX-raymachineandreshapingracketc..Fibercarboncompositematerialalsohasbiologystructurecompatibilityandbloodcompatibility.Ithasgoodstabilityinbiologicalcircumstance.Thusitcanbeusedasbiologicalmedicalmaterial.Furthermore,itcanbeusedasphysicalsportsfabricationmaterialandarchitecturematerial.3.TheoryofUltrasonicTestingTheprincipleofUltrasonicTesting(UT)isshowninFigure1.Ultrasonictransducerisadoptedastransmitterwhichexcitatedstresswaveinsidetheworkpiece.Andinthesamesurface,ultrasonictransducersarealsosetasreceiversateveryfixeddistance.Thetestingpurposeisevaluatingtherelativeefficiencyofstresswavepropagationinsidetheworkpiece.Thebasicpropertyoftestingisadaptedtostresswaveenergytransformation,soitcanbettertestthetransmissionanddistributingofkineticandstressenergy.Theworkpremiseisthat,inthecourseofloading,moreeffectivestressenergyandstressisindicatingtheincreaseofinnerresistance.Thishypothesisisbasedontheconceptofinteractionalstresswave,whichthoughtthatspontaneousstresswaveinthebeginningofrupturewillhelpcrazerapidlyunlesstheirenergy’sexpendingonothermechanismssuchasmicro-crackplasticdeformation.Thatistosay,therapideffectiveconsumptionofstresswaveenergyremovingfromthecrackconcentrationsideneedsthepremiseofenergynotconcentratingorpitchingintodisastrousrupture.Theimportantmeaninginthehypothesisisthatthewaveattenuationcharacteristicofmaterialisveryimportant.Asforcompositematerial,lowattenuationisusuallyreferredtohighintensionandanti-attackability.UTisusuallyreferredtothetestingmethodwhichusingapairofultrasonicpiezoelectrictransducerstosendandreceivetheultrasonicwavetransmissioninthecomponent.Asendingpulsetransducerischosenastheproducingofwave