2012 Vol. 32, No. 3
Display Method:
2012, 32(3): 225-230.
doi: 10.11883/1001-1455(2012)03-0225-06
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Abstract:
Theaxialstressandtheaxialdeformationofthechargeexplosiveinaprojectilewastheoreticallyanalyzedduringthepenetrationprocess. Thecorrespondingdistributionfunctionsalongtheaxis ofthechargeexplosivewereattainedbyconsideringtheelasticandplasticdeformationofthecharge explosive.Basedonthefriction-inducedheataswellastheheatconduction,thetemperaturedistributionalongtheaxisofthechargeexplosivewasobtained. Calculatedresultsshowthatthemaximum temperatureriseanditslocationinthechargeexplosivearedependentonthechargelengthandtheoverloadpeakinadditiontothephysicalpropert parametersoftheexplosive.Thecalculatedcritical chargelengthcanbetakenasareferenceforthechargedesign.Thisinvestigationcanprovideatheoreticalbasisforthechargedesignandthesafetyanalysisintheengineeringpracticeoftheprojectile penetration.
Theaxialstressandtheaxialdeformationofthechargeexplosiveinaprojectilewastheoreticallyanalyzedduringthepenetrationprocess. Thecorrespondingdistributionfunctionsalongtheaxis ofthechargeexplosivewereattainedbyconsideringtheelasticandplasticdeformationofthecharge explosive.Basedonthefriction-inducedheataswellastheheatconduction,thetemperaturedistributionalongtheaxisofthechargeexplosivewasobtained. Calculatedresultsshowthatthemaximum temperatureriseanditslocationinthechargeexplosivearedependentonthechargelengthandtheoverloadpeakinadditiontothephysicalpropert parametersoftheexplosive.Thecalculatedcritical chargelengthcanbetakenasareferenceforthechargedesign.Thisinvestigationcanprovideatheoreticalbasisforthechargedesignandthesafetyanalysisintheengineeringpracticeoftheprojectile penetration.
2012, 32(3): 231-236.
doi: 10.11883/1001-1455(2012)03-0231-06
Abstract:
Dynamicuniaxialcompressionandindirecttensile(Brazilian)testswereconductedforcertaintypicalplastic- bondedexplosivesonasplitHopkinsonpressurebar(SHPB),respectively.The stressequilibriumandconstantstrainrateoflowimpedancematerialswereachievedbyusingthe pulseshapertechnique,andthestress-straincurvesoftheplastic-bondedexplosiveswereobtainedby combiningthesemi-conductorstraingaugesandpiezoelectricityquartzgauges.Basedontheexperimentaldataobtained, thephenomenologicalconstitutivemodelforacertainplastic-bondedexplosive wasproposedbymodifyingtheSarginmodel.Thefractureprocessesontheexplosivesamplesurfaces werecapturedbyusingahigh-speedcamerainthedynamicBraziliantestsandthestrainfieldwascalculatedbythedigitalspecklecorrelationmethod. AndthemodifiedJohnson-Cookmodelswereobtainedforthreekindsoftheplastic- bondedexplosives.Theobtainedmodelsareconsistentwiththe experimentaldata.
Dynamicuniaxialcompressionandindirecttensile(Brazilian)testswereconductedforcertaintypicalplastic- bondedexplosivesonasplitHopkinsonpressurebar(SHPB),respectively.The stressequilibriumandconstantstrainrateoflowimpedancematerialswereachievedbyusingthe pulseshapertechnique,andthestress-straincurvesoftheplastic-bondedexplosiveswereobtainedby combiningthesemi-conductorstraingaugesandpiezoelectricityquartzgauges.Basedontheexperimentaldataobtained, thephenomenologicalconstitutivemodelforacertainplastic-bondedexplosive wasproposedbymodifyingtheSarginmodel.Thefractureprocessesontheexplosivesamplesurfaces werecapturedbyusingahigh-speedcamerainthedynamicBraziliantestsandthestrainfieldwascalculatedbythedigitalspecklecorrelationmethod. AndthemodifiedJohnson-Cookmodelswereobtainedforthreekindsoftheplastic- bondedexplosives.Theobtainedmodelsareconsistentwiththe experimentaldata.
Characteristiccurvemethodforanalyzingmovementofflyerplate
basedonuniversalequationofstateofexplosive
2012, 32(3): 237-242.
doi: 10.11883/1001-1455(2012)03-0237-06
Abstract:
Fromthephysicaldefinitionofperturbationpropagation(Machwaves),thecharacteristic equationsofatwo-dimensionalsupersonicflowwerededucedintotheformswhichwereuncorrelated withtheformulaofEOS.Meanwhile,anewPrantl-Meyerfunctionwasexpressedintoasimplevariablefunctionoffluiddensityalso. Basedoncharacteristicdifference,asolutionmethodofthetwo-dimensionalsupersonicflowwasbuiltup. Therefore,asanapplicationexampleofthesolutionmethod, themovementoftheflyerplatedrivenbyglancingdetonationwasanalyzed.Forcomparison,DetonationdrivesoftheTNTandemulsionexplosiveswerecalculatedwithJWLandpolytropicEOSs. The numericalresultsshowthatcharacteristicdifferencesolutionscompletelyagreewiththeexpanding worksofexplosiveEOSs.
Fromthephysicaldefinitionofperturbationpropagation(Machwaves),thecharacteristic equationsofatwo-dimensionalsupersonicflowwerededucedintotheformswhichwereuncorrelated withtheformulaofEOS.Meanwhile,anewPrantl-Meyerfunctionwasexpressedintoasimplevariablefunctionoffluiddensityalso. Basedoncharacteristicdifference,asolutionmethodofthetwo-dimensionalsupersonicflowwasbuiltup. Therefore,asanapplicationexampleofthesolutionmethod, themovementoftheflyerplatedrivenbyglancingdetonationwasanalyzed.Forcomparison,DetonationdrivesoftheTNTandemulsionexplosiveswerecalculatedwithJWLandpolytropicEOSs. The numericalresultsshowthatcharacteristicdifferencesolutionscompletelyagreewiththeexpanding worksofexplosiveEOSs.
2012, 32(3): 243-250.
doi: 10.11883/1001-1455(2012)03-0243-08
Abstract:
Theignition-growthreactivemodelandadesensitizingmodelwereintroducedintotheselfdevelopedtwo- dimensionalmulticomponentEulerianelastic-plastichydrodynamicscode(MEPH2Y), respectively.Numericalstudieswerecarriedoutonsomedetonativephenomenaincludingtheshock ignition,thediametereffectandtheformationofthedeadzone,withtheaidoftheadaptivemeshrefinementtechnique. Thenumericalresultsshowthatthecomputationcansimulatethemajorcharacteristicsoftheplanardetonationwaves, suchasthedetonationwavespeed,CJstate,vonNeumann spikestateandsoon.Andthediametereffectsoftheexplosivescanbesimulatedcorrectly.Under theconsiderationofthedesensitizingreactivemodel,thedeadzoneformationoftheinsensitivehigh explosivescanalsobereproduced.
Theignition-growthreactivemodelandadesensitizingmodelwereintroducedintotheselfdevelopedtwo- dimensionalmulticomponentEulerianelastic-plastichydrodynamicscode(MEPH2Y), respectively.Numericalstudieswerecarriedoutonsomedetonativephenomenaincludingtheshock ignition,thediametereffectandtheformationofthedeadzone,withtheaidoftheadaptivemeshrefinementtechnique. Thenumericalresultsshowthatthecomputationcansimulatethemajorcharacteristicsoftheplanardetonationwaves, suchasthedetonationwavespeed,CJstate,vonNeumann spikestateandsoon.Andthediametereffectsoftheexplosivescanbesimulatedcorrectly.Under theconsiderationofthedesensitizingreactivemodel,thedeadzoneformationoftheinsensitivehigh explosivescanalsobereproduced.
2012, 32(3): 251-258.
doi: 10.11883/1001-1455(2012)03-0251-08
Abstract:
Toidentifytheanti-explosionperformancesofreinforcedconcrete(RC)slabs,close-inexplosionexperimentswereconductedforsquareRCslabssupportedunidirectionally, inwhichtheRC slabswereloadedbyTNTcharges.BasedonthecommercialhydrocodeAUTODYN,athree-dimensionalsolidmodelincludingexplosive, airandRCslabwithconcreteandreinforcingbarsbeingseparatedwasdevelopedbyusingthegas- solidcoupledtechniquetosimulatethedynamicresponseofthe RCslabs.Inthenumericalsimulation,thestrainrateeffectsweretakenintoaccountonthedynamicalconstitutivebehaviorsofthesophisticatedconcreteandreinforcingbarmaterial .Sequentially,the correspondingdamagemechanismsandfailuremodesoftheRCslabswereanalyzedunderdifferent TNTchargeweights.ThedynamicalevolutionprocessofRCslabswasobservedrealisticallyfrom crackingandbreaking-upoftheconcrete,yieldingandrupturingofreinforcingbarstolocalperforation. ThedamageoftheRCslabsbythenumericalsimulationisingoodagreementwiththeexperimentalresults. AndwiththeincreaseoftheTNTchargeweights,thefailuremodeofRCslabsgraduallychangesfromoverallflexurefailuretolocalpunchingfailure
Toidentifytheanti-explosionperformancesofreinforcedconcrete(RC)slabs,close-inexplosionexperimentswereconductedforsquareRCslabssupportedunidirectionally, inwhichtheRC slabswereloadedbyTNTcharges.BasedonthecommercialhydrocodeAUTODYN,athree-dimensionalsolidmodelincludingexplosive, airandRCslabwithconcreteandreinforcingbarsbeingseparatedwasdevelopedbyusingthegas- solidcoupledtechniquetosimulatethedynamicresponseofthe RCslabs.Inthenumericalsimulation,thestrainrateeffectsweretakenintoaccountonthedynamicalconstitutivebehaviorsofthesophisticatedconcreteandreinforcingbarmaterial .Sequentially,the correspondingdamagemechanismsandfailuremodesoftheRCslabswereanalyzedunderdifferent TNTchargeweights.ThedynamicalevolutionprocessofRCslabswasobservedrealisticallyfrom crackingandbreaking-upoftheconcrete,yieldingandrupturingofreinforcingbarstolocalperforation. ThedamageoftheRCslabsbythenumericalsimulationisingoodagreementwiththeexperimentalresults. AndwiththeincreaseoftheTNTchargeweights,thefailuremodeofRCslabsgraduallychangesfromoverallflexurefailuretolocalpunchingfailure
2012, 32(3): 259-266.
doi: 10.11883/1001-1455(2012)03-0259-08
Abstract:
AdamageimagingmethodusingLambwaveandmatchingpursuitmethodforcontinuous on-linemonitoringofcompositewasproposed.First,asignalprocessingmethodisdevelopedusing matchingpursuits.ItcandecomposeLambsignalsintoalinearexpansionofseveralchirpletatoms withafastoperationspeed.Second,therelationshipbetweenLambwavesdispersionandchirplets chirprateisdeveloped.Itshowsthatthechirpletatomcanmatchthedispersionpulseaccurately,and itcanbeusedtoidentifythemodesofLambwaves.Third,accordingtothesignaldifferencebefore andafterdamage,adamageindexcanbegetfromthedifferencesintheenergycharacteristicsoflamb wave.TheimagethatindicatesthedamagecanbeobtainedbytheRAPIDalgorithm.Theexperimentalresultsdemonstratetheapplicabilityandeffectivenessoftheproposedmethod.
AdamageimagingmethodusingLambwaveandmatchingpursuitmethodforcontinuous on-linemonitoringofcompositewasproposed.First,asignalprocessingmethodisdevelopedusing matchingpursuits.ItcandecomposeLambsignalsintoalinearexpansionofseveralchirpletatoms withafastoperationspeed.Second,therelationshipbetweenLambwavesdispersionandchirplets chirprateisdeveloped.Itshowsthatthechirpletatomcanmatchthedispersionpulseaccurately,and itcanbeusedtoidentifythemodesofLambwaves.Third,accordingtothesignaldifferencebefore andafterdamage,adamageindexcanbegetfromthedifferencesintheenergycharacteristicsoflamb wave.TheimagethatindicatesthedamagecanbeobtainedbytheRAPIDalgorithm.Theexperimentalresultsdemonstratetheapplicabilityandeffectivenessoftheproposedmethod.
2012, 32(3): 267-272.
doi: 10.11883/1001-1455(2012)03-0267-06
Abstract:
Abstract:Undergroundexplosionexperimentswiththeexplosionequivalentof100kgTNTwereperformedindifferentgeologicalmediums, suchasloess,sand-gravelcompositeandgranite.Andthe correspondingsurfacegroundmotionsinducedbyundergroundexplosionswereobservedbyaseriesof seismometers.Byusingtheseobserveddata,thesourceparameterswereobtained,aswellasthe seismiccouplingefficiencyrepresentedbythesteadyvalueofreducedvelocitypotentialatlowfrequencies. Experimentalresultsdisplaythatfortheundergroundexplosionswiththesamescaleddepth ofburialandsameexplosionequivalent,theseismiccouplingefficiencywasstronglydependantonthe sourcemediumpropertyinsuchawaythatthemediumstrengthplaysthemostsignificantrolesindeterminingtheseismiccouplingeffectandthenthe orosityandthewatersaturation.Andbasedonthe experimentaldata,thefeasibilityoftheempiricalformulaproposedbyM.D.Denny,etalwasanalyzedinestimatingtheseismiccouplingeffectofundergroundexplosionswiththeexplosionequivalent of100kgTNT.
Abstract:Undergroundexplosionexperimentswiththeexplosionequivalentof100kgTNTwereperformedindifferentgeologicalmediums, suchasloess,sand-gravelcompositeandgranite.Andthe correspondingsurfacegroundmotionsinducedbyundergroundexplosionswereobservedbyaseriesof seismometers.Byusingtheseobserveddata,thesourceparameterswereobtained,aswellasthe seismiccouplingefficiencyrepresentedbythesteadyvalueofreducedvelocitypotentialatlowfrequencies. Experimentalresultsdisplaythatfortheundergroundexplosionswiththesamescaleddepth ofburialandsameexplosionequivalent,theseismiccouplingefficiencywasstronglydependantonthe sourcemediumpropertyinsuchawaythatthemediumstrengthplaysthemostsignificantrolesindeterminingtheseismiccouplingeffectandthenthe orosityandthewatersaturation.Andbasedonthe experimentaldata,thefeasibilityoftheempiricalformulaproposedbyM.D.Denny,etalwasanalyzedinestimatingtheseismiccouplingeffectofundergroundexplosionswiththeexplosionequivalent of100kgTNT.
2012, 32(3): 273-277.
doi: 10.11883/1001-1455(2012)03-0273-05
Abstract:
LiquidparaffinandRDXexplosiveweremixedintocopperacetateusedasaprecursor.The well-proportionedmixturewasinitiatedinadetonationreactioncontainerthatwasvacuumedtoprepareperfectsphericalnano- coppercrystalparticles.Themorphologyandcompositionofthedetonationsootwereanalyzedbytransmissionelectronmicroscopy (TEM)andX-raydiffraction (XRD). AndthecarbonstructuresinthedetonationsootwerecharacterizedbyRamanspectroscopy.Theresultsindicatethatthestructureofthecoppernano- particlespreparedbythedetonationtechniqueis sphericalwithasmoothsurface.Moreover,thediametersofthecoppernano-particlesaredistributed between150~200nm.Sothedetonationtechniquecanprovideasimpleandrapidwaytopreparecoppernano- particleswithagoodroundness.
LiquidparaffinandRDXexplosiveweremixedintocopperacetateusedasaprecursor.The well-proportionedmixturewasinitiatedinadetonationreactioncontainerthatwasvacuumedtoprepareperfectsphericalnano- coppercrystalparticles.Themorphologyandcompositionofthedetonationsootwereanalyzedbytransmissionelectronmicroscopy (TEM)andX-raydiffraction (XRD). AndthecarbonstructuresinthedetonationsootwerecharacterizedbyRamanspectroscopy.Theresultsindicatethatthestructureofthecoppernano- particlespreparedbythedetonationtechniqueis sphericalwithasmoothsurface.Moreover,thediametersofthecoppernano-particlesaredistributed between150~200nm.Sothedetonationtechniquecanprovideasimpleandrapidwaytopreparecoppernano- particleswithagoodroundness.
2012, 32(3): 278-282.
doi: 10.11883/1001-1455(2012)03-0278-05
Abstract:
Basedonthetwo-dimensionalaxisymmetricEulerequationscouplingwithchemicalreactions, thephenomenaofobliquedetonationinducedbyahypervelocityballinhydrogen-oxygen-nitrogen mixturewerenumericallystudiedbyusingwavepropagationalgorithm withSuperbeelimiter. Theresultsshowthatthestandingdetonationinducedbyaballshowthecompositestructureat Damkohlernumberconditionslightlylargerthanthethreshold,whosestructureiscomposedofa strongoverdrivenobliquedetonation,aweakoverdrivenobliquedetonation,areactingshockwave andainertshockwave.Thereweretwosubsoniczoneandasupersoniczoneintheflowpastasphere afterwave.Thesecondobliqueshockwavewasformedintheleewardsurfaceoftheball.
Basedonthetwo-dimensionalaxisymmetricEulerequationscouplingwithchemicalreactions, thephenomenaofobliquedetonationinducedbyahypervelocityballinhydrogen-oxygen-nitrogen mixturewerenumericallystudiedbyusingwavepropagationalgorithm withSuperbeelimiter. Theresultsshowthatthestandingdetonationinducedbyaballshowthecompositestructureat Damkohlernumberconditionslightlylargerthanthethreshold,whosestructureiscomposedofa strongoverdrivenobliquedetonation,aweakoverdrivenobliquedetonation,areactingshockwave andainertshockwave.Thereweretwosubsoniczoneandasupersoniczoneintheflowpastasphere afterwave.Thesecondobliqueshockwavewasformedintheleewardsurfaceoftheball.
2012, 32(3): 283-290.
doi: 10.11883/1001-1455(2012)03-0283-08
Abstract:
Accordingtothecharacteristicsoftransientplasmaejectorscreatedbyhypervelocityimpact, thesweepLangmuirprobe,thetripleLangmuirprobeandthecoilmeasurementsystemswere establishedtomeasuretheplasmacharacteristicparametersaswellasthemagneticinductionintensity inexpandingplasmacloud.Basedonthegivenlayoutandazimuthangleofthesensors,theelectromagneticcharacteristicmeasurementsofexpandingplasmacloudgeneratedbytheimpactof2024- T4 aluminumprojectilesagainstthe2024-T4aluminumtargetsinthelaboratorywerecarriedoutatthe twoimpactvelocities.Experimentalresultsshowthattheaverageelectrontemperature,electrondensity, andmagneticinductionintensityamplitudevalueare0.4~0.9eV,ontheorderof1012cm-3and 10~20nT,respectively.Byprocessingtheexperimentaldata,therelationshipsbetweenelectron temperature,electrondensityand magneticinductionintensitywereobtained,respectively,atthe givenpositionsoftheprobesandcoilsduringthewholephysicalprocessforthetwoexperiments.And theresultsmeasuredbythesweepLangmuirprobeandthetripleLangmuirprobewerecompared.
Accordingtothecharacteristicsoftransientplasmaejectorscreatedbyhypervelocityimpact, thesweepLangmuirprobe,thetripleLangmuirprobeandthecoilmeasurementsystemswere establishedtomeasuretheplasmacharacteristicparametersaswellasthemagneticinductionintensity inexpandingplasmacloud.Basedonthegivenlayoutandazimuthangleofthesensors,theelectromagneticcharacteristicmeasurementsofexpandingplasmacloudgeneratedbytheimpactof2024- T4 aluminumprojectilesagainstthe2024-T4aluminumtargetsinthelaboratorywerecarriedoutatthe twoimpactvelocities.Experimentalresultsshowthattheaverageelectrontemperature,electrondensity, andmagneticinductionintensityamplitudevalueare0.4~0.9eV,ontheorderof1012cm-3and 10~20nT,respectively.Byprocessingtheexperimentaldata,therelationshipsbetweenelectron temperature,electrondensityand magneticinductionintensitywereobtained,respectively,atthe givenpositionsoftheprobesandcoilsduringthewholephysicalprocessforthetwoexperiments.And theresultsmeasuredbythesweepLangmuirprobeandthetripleLangmuirprobewerecompared.
2012, 32(3): 291-296.
doi: 10.11883/1001-1455(2012)03-0291-06
Abstract:
Aimedathightemperatureandhighpressurecharacteristicsgeneratedfromtoroidalshock wavefocusing,adiscontinuousfiniteelementmethodwasusedtonumericallysimulatetoroidalshock wavefocusinginaco-axiscylindricaltube.Thesimulatedresultsindicatethatthediscontinuousfinite elementmethodcancaptureefficientlythecomplicatedflow-fieldwavestructureswhichincludesecondaryshock wave,vortexring,triplepointandsphericaldouble Machreflectionformedduring shockwavespropagatingintheco-axialcylindricalshocktube.Andfromthesimulatedresults,itcan befoundthattheinnerradiusofthetoroidalpipelinecanaffectmarkedlythevalueandlocationofthe peakpressurealongtheaxisline,andtheouterradiusofthetoroidalpipelineplaysaweakrole.The investigatedresultscanprovideatheoreticalguideforengineeringapplication.
Aimedathightemperatureandhighpressurecharacteristicsgeneratedfromtoroidalshock wavefocusing,adiscontinuousfiniteelementmethodwasusedtonumericallysimulatetoroidalshock wavefocusinginaco-axiscylindricaltube.Thesimulatedresultsindicatethatthediscontinuousfinite elementmethodcancaptureefficientlythecomplicatedflow-fieldwavestructureswhichincludesecondaryshock wave,vortexring,triplepointandsphericaldouble Machreflectionformedduring shockwavespropagatingintheco-axialcylindricalshocktube.Andfromthesimulatedresults,itcan befoundthattheinnerradiusofthetoroidalpipelinecanaffectmarkedlythevalueandlocationofthe peakpressurealongtheaxisline,andtheouterradiusofthetoroidalpipelineplaysaweakrole.The investigatedresultscanprovideatheoreticalguideforengineeringapplication.
2012, 32(3): 297-302.
doi: 10.11883/1001-1455(2012)03-0297-06
Abstract:
ByusinganelectronicuniversaltestingmachineandasplitHopkinsonpressurebardevice, aseriesofuniaxialcompressionexperimentswerecarriedouttoexplorethemechanicalbehaviorsofa 2DwovenC/SiCcompositeinthetemperaturerangefrom293to1273Kandthestrainraterange from10-4to103s-1.Theexperimentalresultsshowasfollows.Thecompositehasexcellenthigh temperaturemechanicalpropertiesinthetestedtemperaturerange.Thecompressivestrengthofthe compositedecreasesnomorethanthirtypercentat1273Kunderquasi-staticcompressionifcompared withthatatroomtemperature.Catastrophicbrittlefailureisnotobservedforthespecimenstestedat differentstrainrates.Withtheincreaseoftheexperimentaltemperature,thecompressivestrengthof the2DC/SiCcompositedecreases,butthedependenceofcompressivestrengthonstrainrateincreases. Atthetemperaturesabove1073K,thesensitivityfactorofcompressivestrengthonstrainrate increasesremarkably.Itisproposedthatthesharpincreaseinthedependenceofcompressivestrength onstrainrateisduetotheoxidationofthecomposites.
ByusinganelectronicuniversaltestingmachineandasplitHopkinsonpressurebardevice, aseriesofuniaxialcompressionexperimentswerecarriedouttoexplorethemechanicalbehaviorsofa 2DwovenC/SiCcompositeinthetemperaturerangefrom293to1273Kandthestrainraterange from10-4to103s-1.Theexperimentalresultsshowasfollows.Thecompositehasexcellenthigh temperaturemechanicalpropertiesinthetestedtemperaturerange.Thecompressivestrengthofthe compositedecreasesnomorethanthirtypercentat1273Kunderquasi-staticcompressionifcompared withthatatroomtemperature.Catastrophicbrittlefailureisnotobservedforthespecimenstestedat differentstrainrates.Withtheincreaseoftheexperimentaltemperature,thecompressivestrengthof the2DC/SiCcompositedecreases,butthedependenceofcompressivestrengthonstrainrateincreases. Atthetemperaturesabove1073K,thesensitivityfactorofcompressivestrengthonstrainrate increasesremarkably.Itisproposedthatthesharpincreaseinthedependenceofcompressivestrength onstrainrateisduetotheoxidationofthecomposites.
2012, 32(3): 303-308.
doi: 10.11883/1001-1455(2012)03-0303-06
Abstract:
Thegenerationcauseofimpactforceduringthemicro-detonationmachiningprocesswasintroduced. Themainprocessingparameterswereconfirmedby meansofsingle-factorexperiments. Basedonaboveparameters,anexponential-typeempiricalmodelforimpactforcewasbuiltbyemployingtheorthogonalexperimentsandtheregressionanalysis. Andtheinfluencesoftheprocessingparametersonimpactforcewereanalyzed. Investigatedresultsdisplaythat:theworkingcurrentandthe workingpressureaswellasthenozzlediameterofthemicro-detonationgeneratorarethemainprocessingparameterstodeterminetheimpactforcemagnitude. Theimpactforcedecreaseswithanincreaseintheworkingcurrentanditincreaseswithincreasesintheworkingpressureandthenozzlediameter. Ontheotherhand,theworkingpulsewidthandtheworkingdistancehaveinsignificantinfluencesontheimpactforcemagnitude. Andtheimpactforcemodelisconsistentwiththeexperimental results.Sotheresearchcanofferanimportantreferencefortheprocesscontrolofmicro-detonation machiningwithstrikingarc.
Thegenerationcauseofimpactforceduringthemicro-detonationmachiningprocesswasintroduced. Themainprocessingparameterswereconfirmedby meansofsingle-factorexperiments. Basedonaboveparameters,anexponential-typeempiricalmodelforimpactforcewasbuiltbyemployingtheorthogonalexperimentsandtheregressionanalysis. Andtheinfluencesoftheprocessingparametersonimpactforcewereanalyzed. Investigatedresultsdisplaythat:theworkingcurrentandthe workingpressureaswellasthenozzlediameterofthemicro-detonationgeneratorarethemainprocessingparameterstodeterminetheimpactforcemagnitude. Theimpactforcedecreaseswithanincreaseintheworkingcurrentanditincreaseswithincreasesintheworkingpressureandthenozzlediameter. Ontheotherhand,theworkingpulsewidthandtheworkingdistancehaveinsignificantinfluencesontheimpactforcemagnitude. Andtheimpactforcemodelisconsistentwiththeexperimental results.Sotheresearchcanofferanimportantreferencefortheprocesscontrolofmicro-detonation machiningwithstrikingarc.
2012, 32(3): 309-315.
doi: 10.11883/1001-1455(2012)03-0309-07
Abstract:
Basedontheexperimentaldataofanunderwatertargetsubjectedtounderwaterexplosion, thetime-frequencycharacteristicsofthemonitoredinterioraccelerationsignalswerestudiedbymeans ofwaveletanalysiswithhighresolvabilityandlocalization.Byusingthesesignals,theaccelerationtimecurvesandtheenergydistributionsindifferentblastingfrequencybandswereobtained. Theanalyzedresultsshowthatthewaveletenergyinagivenfrequencybandcancoinstantaneouslyreflectthe influencesofvibrationstrength,frequency,anddurationonthedamageeffectoftheunderwatertarget. Andthedistributionandattenuationdetailinformationoftheshockwaveandsecondarypressure waveindifferentfrequencybandswasobtainedbycombiningtheacceleration-timecurvesindifferent blastingfrequencybands.Thereby,theinfluencesoftheshockwaveandthesecondarypressurewave onthedamageeffectoftheunderwatertargetcanbeassessed,respectively.
Basedontheexperimentaldataofanunderwatertargetsubjectedtounderwaterexplosion, thetime-frequencycharacteristicsofthemonitoredinterioraccelerationsignalswerestudiedbymeans ofwaveletanalysiswithhighresolvabilityandlocalization.Byusingthesesignals,theaccelerationtimecurvesandtheenergydistributionsindifferentblastingfrequencybandswereobtained. Theanalyzedresultsshowthatthewaveletenergyinagivenfrequencybandcancoinstantaneouslyreflectthe influencesofvibrationstrength,frequency,anddurationonthedamageeffectoftheunderwatertarget. Andthedistributionandattenuationdetailinformationoftheshockwaveandsecondarypressure waveindifferentfrequencybandswasobtainedbycombiningtheacceleration-timecurvesindifferent blastingfrequencybands.Thereby,theinfluencesoftheshockwaveandthesecondarypressurewave onthedamageeffectoftheunderwatertargetcanbeassessed,respectively.
2012, 32(3): 316-322.
doi: 10.11883/1001-1455(2012)03-0316-07
Abstract:
Basedonthesmoothedparticlehydrodynamics(SPH)methodinLS-DYNAsoftware,the shapedchargejetprocesswassimulated.Andthemechanismoftheshapedchargejetwasdiscussed accordingtothenumericalsimulationresults.Toanalyzetheaccuracy,effectivenessandsuperiority aboutthismethod,aswellastheerrorbroughtbydifferentinitialnumbersN oftouchingneighbors perparticle,thenumericalsimulationresultswerecomparedwithtwo-dimensional(2D)finiteelementresultsandtheoreticalcalculations. Theinvestigatedresultsshowthatsomeproblems,suchas griddistortion,windingandcontactpenetrationwhichoftenhappeninthefiniteelementmethod,can beavoidedintheSPH method,sothecalculationprocessbytheSPH methodisstable,andthecalculationprecisionishigherthanthatbythe2Dfiniteelementmethod. Therelativeerrorofthejettip velocityandthejetlengthcalculatedbytheSPH methodcomparedwiththefiniteelementresultsand theoreticalcalculationsarebothlowerthanfivepercent,thereforetheSPH methodisadaptablein multi-material,largedeformationproblemssuchasshapedcharges.ThemostidealNisfrom600to 1800,inwhichtherelativeerrorislowerthan3%andthecomputationalefficiencyishigh.
Basedonthesmoothedparticlehydrodynamics(SPH)methodinLS-DYNAsoftware,the shapedchargejetprocesswassimulated.Andthemechanismoftheshapedchargejetwasdiscussed accordingtothenumericalsimulationresults.Toanalyzetheaccuracy,effectivenessandsuperiority aboutthismethod,aswellastheerrorbroughtbydifferentinitialnumbersN oftouchingneighbors perparticle,thenumericalsimulationresultswerecomparedwithtwo-dimensional(2D)finiteelementresultsandtheoreticalcalculations. Theinvestigatedresultsshowthatsomeproblems,suchas griddistortion,windingandcontactpenetrationwhichoftenhappeninthefiniteelementmethod,can beavoidedintheSPH method,sothecalculationprocessbytheSPH methodisstable,andthecalculationprecisionishigherthanthatbythe2Dfiniteelementmethod. Therelativeerrorofthejettip velocityandthejetlengthcalculatedbytheSPH methodcomparedwiththefiniteelementresultsand theoreticalcalculationsarebothlowerthanfivepercent,thereforetheSPH methodisadaptablein multi-material,largedeformationproblemssuchasshapedcharges.ThemostidealNisfrom600to 1800,inwhichtherelativeerrorislowerthan3%andthecomputationalefficiencyishigh.
2012, 32(3): 323-327.
doi: 10.11883/1001-1455(2012)03-0323-05
Abstract:
Inordertoobtaintheimpactparametersdominatingtheaccuracyandvalidityofgunrecoil simulationexperiments,thevirtualsimulationtestmodelforacertaingunwasdevelopedbasedon MSC.ADAMSsoftware.Andthedevelopedmodelwasappliedtonumericallysimulatethedynamic recoilandcounterrecoilofthegunandtoconducttheuniformdesignexperimentsfortheimpactparameters. Thenumericallysimulatedresultswerecomparedwiththeexperimentalones.Itisshown thattheimpactparametersobtainedbythedevelopedmodelarereasonableandthesimulationtestis valid.
Inordertoobtaintheimpactparametersdominatingtheaccuracyandvalidityofgunrecoil simulationexperiments,thevirtualsimulationtestmodelforacertaingunwasdevelopedbasedon MSC.ADAMSsoftware.Andthedevelopedmodelwasappliedtonumericallysimulatethedynamic recoilandcounterrecoilofthegunandtoconducttheuniformdesignexperimentsfortheimpactparameters. Thenumericallysimulatedresultswerecomparedwiththeexperimentalones.Itisshown thattheimpactparametersobtainedbythedevelopedmodelarereasonableandthesimulationtestis valid.
2012, 32(3): 328-332.
doi: 10.11883/1001-1455(2012)03-0328-05
Abstract:
TodevelopanignitionandgrowthreactionflowmodelforHNS-Ⅳexplosive,cylindertests wereconductedonHNS-ⅣexplosiveandtheexpansionprocessesofthecoppercylinderwallswererecordedbyaGSJhighspeedrotatingmirrorcamera, andparticlevelocitiesattheinterfacebetween HNS-ⅣexplosiveandLiFwindowweremeasuredwithlaservelocityinterferometry(VISAR).The correspondingnumericalsimulationswerecarriedoutbyANSYS/LS-DYNA,respectively.TheJWL equation-of-stateparametersforunreactedexplosivewerefittedtotheavailableshockHugoniotdata. Andbycombiningtheexperimentalresultsandnumericalsimulations,theJWLequation-of-stateparametersfordetonationproductweredetermined, aswellasreactiverateparametersforreactionignitionandgrowthin HNS-Ⅳ explosive.Investigatedresultsshowthatthedevelopedignitionand growthreactionflow modelcanbeusedtopicturethereactionprocessofHNS-Ⅳexplosive,andthe numericallysimulatedresultscanagreewiththeexperimentalones.
TodevelopanignitionandgrowthreactionflowmodelforHNS-Ⅳexplosive,cylindertests wereconductedonHNS-ⅣexplosiveandtheexpansionprocessesofthecoppercylinderwallswererecordedbyaGSJhighspeedrotatingmirrorcamera, andparticlevelocitiesattheinterfacebetween HNS-ⅣexplosiveandLiFwindowweremeasuredwithlaservelocityinterferometry(VISAR).The correspondingnumericalsimulationswerecarriedoutbyANSYS/LS-DYNA,respectively.TheJWL equation-of-stateparametersforunreactedexplosivewerefittedtotheavailableshockHugoniotdata. Andbycombiningtheexperimentalresultsandnumericalsimulations,theJWLequation-of-stateparametersfordetonationproductweredetermined, aswellasreactiverateparametersforreactionignitionandgrowthin HNS-Ⅳ explosive.Investigatedresultsshowthatthedevelopedignitionand growthreactionflow modelcanbeusedtopicturethereactionprocessofHNS-Ⅳexplosive,andthe numericallysimulatedresultscanagreewiththeexperimentalones.
2012, 32(3): 333-336.
doi: 10.11883/1001-1455(2012)03-0333-04
Abstract:
Drop-hammerloadexperimentswereperformedondifferentrocksamples.Bychangingthe drophammerweight,dropheightandpistonrodspacermaterial,transientshockpressurepulsesin therocksampleswererecordedbythepressuregauges.Experimentalresultsindicatethatthepropertiesoftherocksundergothefollowingchangesinducedbydilatancy:( 1)thepermeabilityoftherocks increasesinvaryingdegrees,andthedensertherockis,thegreatertheincreasemultipleofthepermeabilityis;( 2)theelasticmodulusandelasticlimitdecreasewiththeincreaseofrockvolume;(3) thepropagationvelocitiesoflongitudinalandtransversewavesdecreaseintherocks;(4)theporosities intherocksincreaseduetotheextensionofthenew-producedorinherentmicro-cracksintherocks.
Drop-hammerloadexperimentswereperformedondifferentrocksamples.Bychangingthe drophammerweight,dropheightandpistonrodspacermaterial,transientshockpressurepulsesin therocksampleswererecordedbythepressuregauges.Experimentalresultsindicatethatthepropertiesoftherocksundergothefollowingchangesinducedbydilatancy:( 1)thepermeabilityoftherocks increasesinvaryingdegrees,andthedensertherockis,thegreatertheincreasemultipleofthepermeabilityis;( 2)theelasticmodulusandelasticlimitdecreasewiththeincreaseofrockvolume;(3) thepropagationvelocitiesoflongitudinalandtransversewavesdecreaseintherocks;(4)theporosities intherocksincreaseduetotheextensionofthenew-producedorinherentmicro-cracksintherocks.
