瑞利波反射理论探讨

,(,710038):,,,(),,,:;;;:TG115.28+5:A:100026656(2001)1120472203RESEARCHONREFLECTIONTHEORYOFRAYLEIGHWAVESZHANGBo,LIJian2jun(AirForceEngineeringUniversity,Xipan710038,China)Abstract:OnthebasisofRayleighwavetheory,assumingthesurfacewavespropagatingintheformofcylindricalwavesandconsideringthelawofparticledisplacementamplitudesattenuatingexponentiallybydepthandthepropertyofacousticfieldbeingbasicallywithintwowavelengths,theproblemofend(infiniteboundary)reflectedacousticpressurewassimpletohandle.Thereflectedacousticenergyfromcrackedsurfaceintheformofcylindricalwaveswasadoptedtodealwiththeproblemoftheacousticreflectionfromfinitecrackedsurface.Thus,theacousticpressurewhichwasdirectlyproportionaltosignalamplitudewasdeduced.Thetheoreticalresultsofsurfacewavereflectionweregivenandwellveri2fiedbyexperiments.Keywords:Ultrasonictesting;Surfacewave;Reflectedacousticpressure;Crack()[1,2],,11.11885,,,VR,x,z,1,:20002062261[3]u=Ae-az-be-czsint-2x(1)w=Be-az-be-czcost-2x(2)uxwzta,b,b,c,2742311200111NDTVol.23No.11Nov.2001©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.A,B(1),(2)u=Uzsin(t-kx)(3)w=Wzcos(t-kx)(4)UzxUz=Ae-az-be-czWzzWz=Be-az-be-czk=2(3),(4)u2U2z+w2W2z=1(5)(5),=0.29,UzW(0),WzW(0),z,22W(0)(z=0)z,2:(1)UzW(0)WzW(0)zz=2,WzW(0)1%(-40dB),UzW(0)1%z=2,(2)WzW(0)UzW(0)Wz,Wz(3)z=0.183,Uz=0,,Uzz=0.183,z,,,,VR=0.87+1.121+VS(6)VRVS,VR=0.926VS1.23,,O(,)P=BSxe-xe-az-be-cz(7)SOxP374:©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.3P=DRBS2xe-2xe-az-be-cz(8)RDO,OBB=20PWdz=DRBSW2xe-2x20e-az-be-czdz(9)WOxPCPC=RBSxe-xe-az-be-cz(10)OxJxJx=P2C2c(11)cL,nJJ=n0JxLdz0n2J=LR2B2S22cxe-2xn0e-az-be-cz2dz(12)O€J0€J0=Jxne-2x(13)OŠPCŠPC=D2cJ0(14)OCC=ŠPCWn(15)(10)(15)C=DRBSWLnxe-2xn0e-az-be-cz2dz12(16)(9),(16)()BC=x2Ln1220e-az-be-cz2dzn0e-az-be-cz2dz12(17),=0.29,a=5.429,b=1.750,c=2.376,=0.598mm(5MHz)n,,0.17(16)n0.17=7.487nn0e-az-be-cz2dz12(18)22.1CTS223,,5MHz(4),,42.2d=0.17,n=0.17,L=7mm,(17)1,(18)23,(18),1x/mm20lgBC/dBx/mm20lgBC/dB3020.52205022.73224021.76216023.5323(478)474:©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.,TDR,:(1),TDR(2)5minTDR,0151h(3)TDR,(4)TDR,(5)TDR,,TDR,,;,,TDR,,:[1],.[J].,1999,7(3):200-206.[2],.[J].,1999,15(4):1-6.[3]KaneWF,BeckTJ.Rapidslopemonitoring[J].CivilEngineering,1996,66(6):56-58.[4]OConnorKM.Developmentofsystemforhighwallmonitoringusingtimedomainreflectometry[R].Min2neapolis:USBureauofMinesTwinCitiesResearchCenter,1991.75.[5]AndrewsJR.Timedomainreflectometry[A].Proceed2ingsofSymposiumandWorkshoponTimeDomainRe2flectometryinEnvironmental,Infrastructure,andMin2ingApplications[C].NorthwesternUniversity,USBu2reauofMinesSpecialPublicationSP-1994,1994.4-13.[6]DowdingCH,SuMB,OConnorK.Principlesoftimedomainreflectometryappliedtomeasurementsofrockmassdeformation[J].InternationalJournalofRockMe2chanics,MiningScience,&GeomechanicsAbstract,1988,26:287-297.(474)2nd=nmm20lgn0.17/dBnd=nmm20lgn0.17/dB0.170.1001.500.9013.80.500.308.22.001.2015.11.000.6012.03nd=nmm20lgn0.17/dBnd=nmm20lgn0.17/dB0.170.1001.300.78140.270.1651.911.14150.700.4292.241.34151.150.69135,5d=(n)mm,v=20lgn0.17dBd()dBd50.08mm:[1]19.[M].:,1974.[2]LidingtonBH,etal.Crackdepthmeasurementsusingasinglesurfacewaveprobe[J].TheBritishJournalofNon2DestructiveTesting,1975,17(6):165.[3]H.,,.[M].:,1958.874:©1995-2004TsinghuaTongfangOpticalDiscCo.,Ltd.Allrightsreserved.