2010 Vol. 30, No. 6
Display Method:
2010, 30(6): 561-568.
doi: 10.11883/1001-1455(2010)06-0561-08
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Abstract:
Aninvestigationondynamicresponseofclampedsandwichbeamswithaluminumfoam coresandmonolithicbeamswasachievedbyusingaluminumfoamprojectileloading.LDVdeviceand Laserdisplacementtransducerwereappliedto measureimpactvelocityofprojectileanddeflectiontimehistoryofthemid- pointofbackfaceofthebeam,respectively.Andthentheeffectsofapplied impulse,face-sheetthickness,andcorethicknessontheresponseofstructureswerestudied.Deformationandfailuremodesofsandwichbeamsareexhibitedaccordingtoexperimentalinvestigation. The resultsindicatethatthestructuralresponseissensitivetotheconfigurationofsandwichstructures. Thepermanentdeflectionofthemid-pointofbackfaceispresentedproportionalrelationshipwithappliedimpulseandface- sheetthickness,respectively.Comparingwithmonolithicbeamsofthesame mass,theresultshowsthatsandwichbeamshaveasuperiorshockresistance.Theexperimentalresultsareofworthtooptimumdesignofcellularmetallicsandwichstructures
Aninvestigationondynamicresponseofclampedsandwichbeamswithaluminumfoam coresandmonolithicbeamswasachievedbyusingaluminumfoamprojectileloading.LDVdeviceand Laserdisplacementtransducerwereappliedto measureimpactvelocityofprojectileanddeflectiontimehistoryofthemid- pointofbackfaceofthebeam,respectively.Andthentheeffectsofapplied impulse,face-sheetthickness,andcorethicknessontheresponseofstructureswerestudied.Deformationandfailuremodesofsandwichbeamsareexhibitedaccordingtoexperimentalinvestigation. The resultsindicatethatthestructuralresponseissensitivetotheconfigurationofsandwichstructures. Thepermanentdeflectionofthemid-pointofbackfaceispresentedproportionalrelationshipwithappliedimpulseandface- sheetthickness,respectively.Comparingwithmonolithicbeamsofthesame mass,theresultshowsthatsandwichbeamshaveasuperiorshockresistance.Theexperimentalresultsareofworthtooptimumdesignofcellularmetallicsandwichstructures
2010, 30(6): 569-576.
doi: 10.11883/1001-1455(2010)06-0569-08
Abstract:
Thegenerationandflightoffragmentsarestochasticandcancausemoreseverehazards. Studyingonthedominoeffectstudycausedbythefragmentsfromexplosionishotspotanddifficulty. Basedondynamicanalysis,thepresentworkextendedthetwo-dimensionalfragmenttrajectoryequationintothree- dimensionalsystem,andtookwindintoaccount.ThepresentanalysistookacylindricaltankinMexicoCitywithboilingliquidexpandingvaporexplosionasanexample, andthetrajectoryoffragmentwassimulatedbyMonte- Carlomethod.Seenfromtheprobabilitiesoffragmentranges tobereachedwith/withoutwind,windhaslessimpactonthehazardcausedbyfragments.Theimpactprobabilityofafragmentonatargetwithnowindwasattained, impactprobabilitywiththetank showedtheincreaseofdistancebetweenthestrictexponentialdecaytrend,andthroughthisrelationship, thetankspacingincompliancewithsafetyrequirementscanbecalculated.Thepaperprovidesa methodwhichisofgreatsignificancefortheriskassessmentandcontroloffragmentsfromtheexplosionofcylindricaltanks.
Thegenerationandflightoffragmentsarestochasticandcancausemoreseverehazards. Studyingonthedominoeffectstudycausedbythefragmentsfromexplosionishotspotanddifficulty. Basedondynamicanalysis,thepresentworkextendedthetwo-dimensionalfragmenttrajectoryequationintothree- dimensionalsystem,andtookwindintoaccount.ThepresentanalysistookacylindricaltankinMexicoCitywithboilingliquidexpandingvaporexplosionasanexample, andthetrajectoryoffragmentwassimulatedbyMonte- Carlomethod.Seenfromtheprobabilitiesoffragmentranges tobereachedwith/withoutwind,windhaslessimpactonthehazardcausedbyfragments.Theimpactprobabilityofafragmentonatargetwithnowindwasattained, impactprobabilitywiththetank showedtheincreaseofdistancebetweenthestrictexponentialdecaytrend,andthroughthisrelationship, thetankspacingincompliancewithsafetyrequirementscanbecalculated.Thepaperprovidesa methodwhichisofgreatsignificancefortheriskassessmentandcontroloffragmentsfromtheexplosionofcylindricaltanks.
2010, 30(6): 577-582.
doi: 10.11883/1001-1455(2010)06-0577-06
Abstract:
Atheoryanalysisofmovementandstressstateofexplosionexpandingringhasbeencarried out.Theresultsshowthatone-dimensionalstresspresumemaybringoutthedepartureofvelocity andstressofring.Thedepartureofvelocityandstresshasbeenestimatedbytheoryanalysis.The stresscalculatedbyvelocityofoutersurfaceofringislargerthantheaveragestressonthesectionof ring.Thenumericalsimulationhasvalidatedtheresultsfromtheoryanalysis,anddeterminedthe rangeofstressdeparturecarriedbyone-dimensionalstresspresume.
Atheoryanalysisofmovementandstressstateofexplosionexpandingringhasbeencarried out.Theresultsshowthatone-dimensionalstresspresumemaybringoutthedepartureofvelocity andstressofring.Thedepartureofvelocityandstresshasbeenestimatedbytheoryanalysis.The stresscalculatedbyvelocityofoutersurfaceofringislargerthantheaveragestressonthesectionof ring.Thenumericalsimulationhasvalidatedtheresultsfromtheoryanalysis,anddeterminedthe rangeofstressdeparturecarriedbyone-dimensionalstresspresume.
2010, 30(6): 583-587.
doi: 10.11883/1001-1455(2010)06-0583-05
Abstract:
BasedonPKTangsopinionthatonlythehigh-pressuretermofJones-Wilkins-Leeequationofstate( JWLEOS)neededtobemodifiedwhenusedforoverdrivendetonation,themodified termoftheinternalenergyisentropiccurvewaspresentedandthemodifiedtermofthepressureisentropiccurvewasobtainedfromthedifferential ormoftheinternalenergyisentropiccurvebyapplying thefirstlawofthermodynamics.AndthreemodifiedJWLequationsofstateforoverdrivendetonation productsofJB-9014explosiveweregainedbyfittingsimultaneouslytheshockHugoniotpressureand soundvelocitydata.Resultsshowthat,themodifiedtermsgainedinthispapercanmodelHugoniot dataforoverdrivendetonationreasonablyaswellasPKTangs,andtheprecisionisalittleworseout oftherangeofexperimentaldata
BasedonPKTangsopinionthatonlythehigh-pressuretermofJones-Wilkins-Leeequationofstate( JWLEOS)neededtobemodifiedwhenusedforoverdrivendetonation,themodified termoftheinternalenergyisentropiccurvewaspresentedandthemodifiedtermofthepressureisentropiccurvewasobtainedfromthedifferential ormoftheinternalenergyisentropiccurvebyapplying thefirstlawofthermodynamics.AndthreemodifiedJWLequationsofstateforoverdrivendetonation productsofJB-9014explosiveweregainedbyfittingsimultaneouslytheshockHugoniotpressureand soundvelocitydata.Resultsshowthat,themodifiedtermsgainedinthispapercanmodelHugoniot dataforoverdrivendetonationreasonablyaswellasPKTangs,andtheprecisionisalittleworseout oftherangeofexperimentaldata
2010, 30(6): 588-592.
doi: 10.11883/1001-1455(2010)06-0588-05
Abstract:
Thedeflagrationtodetonationtransition(DDT)processesinstoichiometricthree-phasefuel/ airexplosives,whichincludenitromethane/aluminum powder/air,isopropylnitrate/aluminum powder/airandethylether/aluminumpowder/air,werestudiedexperimentallybyusingthemultiphasecombustionanddetonationexperimentalsystem. Andthecombustionanddetonationperformancesofdifferent3- phasemixtureswereanalyzed.Thegeneralregulationofthe3-phasemixtureDDT wasobtained.Theresultsshowthatthecombustionanddetonationperformancesofthe3-phasemixturevarywiththemassconcentration.
Thedeflagrationtodetonationtransition(DDT)processesinstoichiometricthree-phasefuel/ airexplosives,whichincludenitromethane/aluminum powder/air,isopropylnitrate/aluminum powder/airandethylether/aluminumpowder/air,werestudiedexperimentallybyusingthemultiphasecombustionanddetonationexperimentalsystem. Andthecombustionanddetonationperformancesofdifferent3- phasemixtureswereanalyzed.Thegeneralregulationofthe3-phasemixtureDDT wasobtained.Theresultsshowthatthecombustionanddetonationperformancesofthe3-phasemixturevarywiththemassconcentration.
2010, 30(6): 593-597.
doi: 10.11883/1001-1455(2010)06-0593-05
Abstract:
Therectangulardetonationflowfieldfilledwithhydrogen-airissimulatednumericallybased onmulticomponenttwo-dimensionalEulerequation,andeffectsofuniformincomingflowondetonationwavepropagationwerediscussed. Fromthenumericalresults,dependingontheflowvelocity, theapparentpropagationvelocityofadetonationwaveishigherintheupstreamdirectionandlowerin thedownstreamdirectionthanvC-J.Thepressureoftheupstream movingdetonationishigherthan thatofthedownstream movingdetonation.Asaresult,investigationofdetonationwavepropagation inaflowsystembyclassicalC-Jdetonationtheoryisunsuitable.
Therectangulardetonationflowfieldfilledwithhydrogen-airissimulatednumericallybased onmulticomponenttwo-dimensionalEulerequation,andeffectsofuniformincomingflowondetonationwavepropagationwerediscussed. Fromthenumericalresults,dependingontheflowvelocity, theapparentpropagationvelocityofadetonationwaveishigherintheupstreamdirectionandlowerin thedownstreamdirectionthanvC-J.Thepressureoftheupstream movingdetonationishigherthan thatofthedownstream movingdetonation.Asaresult,investigationofdetonationwavepropagation inaflowsystembyclassicalC-Jdetonationtheoryisunsuitable.
2010, 30(6): 598-606.
doi: 10.11883/1001-1455(2010)06-0598-09
Abstract:
Thebendingoftheprojectileintheprocessofhigh-speedpenetratingconcreteisstudiedby simplifyingtheprojectileasafree-freebeam.Thebending momentcausedbythetransverseload whichisgeneratedfromsmallangleofattackandpenetrationresistanceisanalyzedthroughtheoreticalwork. Theanalysisshowedthatthetheoreticalbendingconditionisdominatedbyinitialstatus, structureandmaterialoftheprojectile.Thecomputedresultsprovedthatthebendingofhigh-speed penetratingprojectileisaffectedbytheexistenceofsmallangleofattack.Thepenetrationexperiment alsoindicatesthatthebendingpositionandthebendingconditionobtainedfromexperimentresultsare wellagreedwiththeoreticalanalysis.
Thebendingoftheprojectileintheprocessofhigh-speedpenetratingconcreteisstudiedby simplifyingtheprojectileasafree-freebeam.Thebending momentcausedbythetransverseload whichisgeneratedfromsmallangleofattackandpenetrationresistanceisanalyzedthroughtheoreticalwork. Theanalysisshowedthatthetheoreticalbendingconditionisdominatedbyinitialstatus, structureandmaterialoftheprojectile.Thecomputedresultsprovedthatthebendingofhigh-speed penetratingprojectileisaffectedbytheexistenceofsmallangleofattack.Thepenetrationexperiment alsoindicatesthatthebendingpositionandthebendingconditionobtainedfromexperimentresultsare wellagreedwiththeoreticalanalysis.
2010, 30(6): 607-613.
doi: 10.11883/1001-1455(2010)06-0607-07
Abstract:
Thebasicprinciplesofchimneyblastingdemolitionwereintroduced.Aimedtothecollapsingprocessofchimneys, themechanicalmodelsweredevelopedtoderivethelargestrangesofchimneybendingmomentandshearstressbythemathematicalmethods. Andthecollapsingprocessesof chimneysweresimulatednumericallybyusingthefiniteelementsoftwareLS-DYNA3Dandthesimulatedresultswerecomparedwiththeactualcollapsingprocessofchimneys. ItisrevealedthatthefiniteelementsoftwareLS- DYNA3Dcanbeusedtostimulatethecollapsingprocessofchimneyblasting, forinstance,thepartsatthedistancesfromthegroundabout1/3,1/2,and2/3,wherethere arestressconcentrationphenomena,areeasilytobebrokenduringthecollapsingprocess.Thebroken partandtimeofthechimneylinkscloselytothecuttingshapeandthephysicalandmechanicalpropertiesofthestructureitself. Thereisobviousdifferencebetweenthebrickchimneyandreinforcedconcretechimney.
Thebasicprinciplesofchimneyblastingdemolitionwereintroduced.Aimedtothecollapsingprocessofchimneys, themechanicalmodelsweredevelopedtoderivethelargestrangesofchimneybendingmomentandshearstressbythemathematicalmethods. Andthecollapsingprocessesof chimneysweresimulatednumericallybyusingthefiniteelementsoftwareLS-DYNA3Dandthesimulatedresultswerecomparedwiththeactualcollapsingprocessofchimneys. ItisrevealedthatthefiniteelementsoftwareLS- DYNA3Dcanbeusedtostimulatethecollapsingprocessofchimneyblasting, forinstance,thepartsatthedistancesfromthegroundabout1/3,1/2,and2/3,wherethere arestressconcentrationphenomena,areeasilytobebrokenduringthecollapsingprocess.Thebroken partandtimeofthechimneylinkscloselytothecuttingshapeandthephysicalandmechanicalpropertiesofthestructureitself. Thereisobviousdifferencebetweenthebrickchimneyandreinforcedconcretechimney.
2010, 30(6): 614-621.
doi: 10.11883/1001-1455(2010)06-0614-08
Abstract:
Thethermoelasticcouplingstabilityoftheaxiallymovingbeamundertheactionofuniformlydistributedtangentialfollowerforceswasinvestig ted.Thedifferentialequationofmotionforthe axiallymovingbeamundertheactionofuniformlydistributedtangentialfollowerforceswasestablished, andtheeigenequationfortheaxiallymovingbeamwithtwokindsofboundaryconditionssubjectedtofollowerforceswasderivedbyanormalizedpowe seriesmethod.Thefirstthreeordersdimensionlesscomplexfrequenciesofthesystem werecalculated,andtheeffectsofthedimensionless movingspeed,thedimensionlessthermoelasticcouplingfactor,thedimensionlessfollowerforceson thestabilityoftheaxiallymovingbeaminthethermoelasticcouplingcasewereanalyzed.
Thethermoelasticcouplingstabilityoftheaxiallymovingbeamundertheactionofuniformlydistributedtangentialfollowerforceswasinvestig ted.Thedifferentialequationofmotionforthe axiallymovingbeamundertheactionofuniformlydistributedtangentialfollowerforceswasestablished, andtheeigenequationfortheaxiallymovingbeamwithtwokindsofboundaryconditionssubjectedtofollowerforceswasderivedbyanormalizedpowe seriesmethod.Thefirstthreeordersdimensionlesscomplexfrequenciesofthesystem werecalculated,andtheeffectsofthedimensionless movingspeed,thedimensionlessthermoelasticcouplingfactor,thedimensionlessfollowerforceson thestabilityoftheaxiallymovingbeaminthethermoelasticcouplingcasewereanalyzed.
2010, 30(6): 622-627.
doi: 10.11883/1001-1455(2010)06-0622-06
Abstract:
Accordingtothechaostheory,basedonavastamountofprimarydataofsmall-scalecompartmentfireexperiments, anewflashovercriterionwhichareindicatedbythetemperatureriserate areputforward.Bythetestedresultsoflarge-scalefires,thepracticalityofthecriterionisinitially verified.Theresultsshowthatthiscriterioncanbeusedtopredictthelikelihoodofflashoverinlargescalerealenclosurefires.
Accordingtothechaostheory,basedonavastamountofprimarydataofsmall-scalecompartmentfireexperiments, anewflashovercriterionwhichareindicatedbythetemperatureriserate areputforward.Bythetestedresultsoflarge-scalefires,thepracticalityofthecriterionisinitially verified.Theresultsshowthatthiscriterioncanbeusedtopredictthelikelihoodofflashoverinlargescalerealenclosurefires.
2010, 30(6): 628-632.
doi: 10.11883/1001-1455(2010)06-0628-05
Abstract:
Inallusiontolackresearchofrocketsledwater-brakehighspeedenteringintowater,the methodoffluid-solidcouplingwasusedtonumericallyresearch.Themodalitiesofwaterwerecalculatedsuchassupercavitation, uplist,spatterandpressure.Thevelocity,decelerationandresistance coefficientvariedwithtimeofwater-brakeweregained.Numericalresearchshowsasfollows:thesupercavitationgeneratedfrom water-brake'sknifebitandsideboardnoseaffectsthewaterresistance heavily,wateruplistaffectssubordinatelyandwaterspatterultimatelyhasnoeffect;steppedwaterentryconfigurationsofwater- breakcaneffectivelyreducepeakvalueofimpactforce.Thismethodaffordsbasesfordesigningrocketsledwater- brakeandreferencesforstudyingothercorrelativebodies highspeedwater-entry.
Inallusiontolackresearchofrocketsledwater-brakehighspeedenteringintowater,the methodoffluid-solidcouplingwasusedtonumericallyresearch.Themodalitiesofwaterwerecalculatedsuchassupercavitation, uplist,spatterandpressure.Thevelocity,decelerationandresistance coefficientvariedwithtimeofwater-brakeweregained.Numericalresearchshowsasfollows:thesupercavitationgeneratedfrom water-brake'sknifebitandsideboardnoseaffectsthewaterresistance heavily,wateruplistaffectssubordinatelyandwaterspatterultimatelyhasnoeffect;steppedwaterentryconfigurationsofwater- breakcaneffectivelyreducepeakvalueofimpactforce.Thismethodaffordsbasesfordesigningrocketsledwater- brakeandreferencesforstudyingothercorrelativebodies highspeedwater-entry.
2010, 30(6): 633-640.
doi: 10.11883/1001-1455(2010)06-0633-08
Abstract:
Accordingtothekinematicalmechanismcomplexityoftheimpactedpressurizedliquidcolumninthehighenergygasfracturingprocess, weassumesthatthecompletelycontactedgasliquidinterfaceexits. ThenbyusingaLagrangeanalyticalmethodforstudyingarandomliquidacross-section, adynamicmodelofthepressurizedliquidcolumnmovementlawissetup,whichcomprisescontinuityequation, momentumconservativeequationandenergyconservativeequation.Basedonthe pressureandvolumeconservationduringtheprocessofpowderconflagrationandpressurizedliquid columnmovement,acouplingnumericalmethodfordescribingthegas-liquidinterfacemovementlaw isestablished.Examplecalculationsshowthatwhenconsideringthemacroscopicalpropelandimpact compressiononthepressurizedliquidcolumncausedbydeflagration,dynamicenergydistributionof theliquiddistributionandpipecolumnfrictionresistance,theinterfaceascendingheightislimited (lessthan0.1mintheexampleconditions).Thisillustratesthatpressurizedliquidcolumnhasagood functionofbackingpressure.Butinfact,inthefracturingprocess,theinterfacecanreachahigher position(18.9m),whichshowsthatinthelaterprocess,hydraulicoscillationproducesanobvious synergisticeffect.
Accordingtothekinematicalmechanismcomplexityoftheimpactedpressurizedliquidcolumninthehighenergygasfracturingprocess, weassumesthatthecompletelycontactedgasliquidinterfaceexits. ThenbyusingaLagrangeanalyticalmethodforstudyingarandomliquidacross-section, adynamicmodelofthepressurizedliquidcolumnmovementlawissetup,whichcomprisescontinuityequation, momentumconservativeequationandenergyconservativeequation.Basedonthe pressureandvolumeconservationduringtheprocessofpowderconflagrationandpressurizedliquid columnmovement,acouplingnumericalmethodfordescribingthegas-liquidinterfacemovementlaw isestablished.Examplecalculationsshowthatwhenconsideringthemacroscopicalpropelandimpact compressiononthepressurizedliquidcolumncausedbydeflagration,dynamicenergydistributionof theliquiddistributionandpipecolumnfrictionresistance,theinterfaceascendingheightislimited (lessthan0.1mintheexampleconditions).Thisillustratesthatpressurizedliquidcolumnhasagood functionofbackingpressure.Butinfact,inthefracturingprocess,theinterfacecanreachahigher position(18.9m),whichshowsthatinthelaterprocess,hydraulicoscillationproducesanobvious synergisticeffect.
2010, 30(6): 641-646.
doi: 10.11883/1001-1455(2010)06-0641-06
Abstract:
Strainrateeffecttests,limitedstraintestsandcumulatedstraintestswereconductedona vanadium-basedalloy(V-5Cr-5Ti)respectivelybyusingasplit-Hopkinsonpressurebar(SHPB)systematroomtemperature. Theeffectsofstrainrateandstraincumulatingonthedynamiccompressive mechanicalpropertiesofV-5Cr-5Tiwereanalyzed.Themicrostructuresofthespecimensbeforeand afterdynamiccompressionwereinvestigatedbyapplyinganopticalmicroscope.TheexperimentalresultsshowthatthedynamicpropertiesofV- 5Cr-5Tiexhibitobvioussensitivitytothestrainratesand thestrainhistory,andtheeffectofstrainhistoryismoreobvious.Forspecimensathighstrainrates, thetwinsappearwhenthestrainissmallerthan0.20,andthetwinsdecreasewhilethestrainislarger than0.20.
Strainrateeffecttests,limitedstraintestsandcumulatedstraintestswereconductedona vanadium-basedalloy(V-5Cr-5Ti)respectivelybyusingasplit-Hopkinsonpressurebar(SHPB)systematroomtemperature. Theeffectsofstrainrateandstraincumulatingonthedynamiccompressive mechanicalpropertiesofV-5Cr-5Tiwereanalyzed.Themicrostructuresofthespecimensbeforeand afterdynamiccompressionwereinvestigatedbyapplyinganopticalmicroscope.TheexperimentalresultsshowthatthedynamicpropertiesofV- 5Cr-5Tiexhibitobvioussensitivitytothestrainratesand thestrainhistory,andtheeffectofstrainhistoryismoreobvious.Forspecimensathighstrainrates, thetwinsappearwhenthestrainissmallerthan0.20,andthetwinsdecreasewhilethestrainislarger than0.20.
2010, 30(6): 647-651.
doi: 10.11883/1001-1455(2010)06-0647-05
Abstract:
TheequationofstateofgasdetonationproductswasdescribedbyRosssmodificationof hard-spherevariationtheoryandtheimprovedone-fluidvanderWaalsmixturemodel.TheGibbsfree energyofdissociatedcarbonwascalculatedforthemostprobablestate,whichwasdeterminedbydistinguishingthefollowingfourstatesofcarbon: graphite,diamond,graphitelikeanddiamondlike. Theequilibriumcompositionsofdetonationproductsarecalculatedbysolvingchemicalequilibriumequationsbasedonminimizingfreeenergy. ThedetonationpropertiesattheCJpointofPBX9502explosivewerecalculatedwiththistheory. Theresultsshowsatisfactoryagreementwiththeexperimentaldata. Comparisonoftheisothermalpressure-densitycurvesdisplaysthattheresultscalculated withthepresenttheoryareingoodagreementwiththosebasedonSesamedatabaseathightemperature. Aslopeisfoundat5802Kisotherm.Thereasonisthatthecarbonphaseischangedatthis point.
TheequationofstateofgasdetonationproductswasdescribedbyRosssmodificationof hard-spherevariationtheoryandtheimprovedone-fluidvanderWaalsmixturemodel.TheGibbsfree energyofdissociatedcarbonwascalculatedforthemostprobablestate,whichwasdeterminedbydistinguishingthefollowingfourstatesofcarbon: graphite,diamond,graphitelikeanddiamondlike. Theequilibriumcompositionsofdetonationproductsarecalculatedbysolvingchemicalequilibriumequationsbasedonminimizingfreeenergy. ThedetonationpropertiesattheCJpointofPBX9502explosivewerecalculatedwiththistheory. Theresultsshowsatisfactoryagreementwiththeexperimentaldata. Comparisonoftheisothermalpressure-densitycurvesdisplaysthattheresultscalculated withthepresenttheoryareingoodagreementwiththosebasedonSesamedatabaseathightemperature. Aslopeisfoundat5802Kisotherm.Thereasonisthatthecarbonphaseischangedatthis point.
2010, 30(6): 652-657.
doi: 10.11883/1001-1455(2010)06-0652-06
Abstract:
Thedispersionofmetalparticlesbyexplosivewasinvestigatedexperimentallywithdifferent chargeformsofexplosiveand metalparticles:separationform (withandwithoutdispersant)and mixtureform.Theresultsshowthattheparticlesarepartlysinteredandarenotevendistributedin theseparationform withoutdispersant.Theparticlesaredispersedingood-distributionandnoparticleissinteredintheseparationform withdispersantaswellasinthemixtureform.Consideringthe numberdensityandthepenetrationontargetoftheparticles,thechargingmanufacturabilityandsafety, separationform withdispersantisbetterthantheothers.
Thedispersionofmetalparticlesbyexplosivewasinvestigatedexperimentallywithdifferent chargeformsofexplosiveand metalparticles:separationform (withandwithoutdispersant)and mixtureform.Theresultsshowthattheparticlesarepartlysinteredandarenotevendistributedin theseparationform withoutdispersant.Theparticlesaredispersedingood-distributionandnoparticleissinteredintheseparationform withdispersantaswellasinthemixtureform.Consideringthe numberdensityandthepenetrationontargetoftheparticles,thechargingmanufacturabilityandsafety, separationform withdispersantisbetterthantheothers.
2010, 30(6): 658-663.
doi: 10.11883/1001-1455(2010)06-0658-06
Abstract:
Toinvestigatethecaseoffragmentsdroppingandcombustionpropertychangingofbase bleedpropellantgrainresultingfromtheeffectofencroachmentanddesquamationcausedbythejetof ignition,thesemi-closedbombwasusedtosimulatethestageofrapiddepressurizationafterbase bleedprojectileflightoutofthenozzle.Theserialimagesofignitionandcombustionofbasebleed propellantgrainwererecordedbymeansofhighspeedvideosystem.Themathematicmodelofcombustionofbasebleedpropellantinthesemi- closedbombwasbuilt.Thechangesofaveragepressure, massflowrateandcombustiontimefordifferentqualityoftotalfragmentswerecalculatedandanalyzed. Thestudyresultsareasfollows:Thephenomenonofencroachmentanddesquamationhappen atinitialstagesofignition;Thefragmentsaredesquamatedfromthepartofbasebleedpropellant grainnotbeingignited;Theeffectofencroachmentanddesquamationiscausedbytheencroachment andimpactofignitionjet;Themassofallfragmentsis(7-9)percentoftheinitialmassofthebase bleedpropellant;Theactionofencroachmentanddesquamationaffectsseriouslytheconsistenciesof ignitionofigniterandcombustionofbasebleedpropellantgrain.Thecalculationresultsagreewell withtheexperimentalresults.
Toinvestigatethecaseoffragmentsdroppingandcombustionpropertychangingofbase bleedpropellantgrainresultingfromtheeffectofencroachmentanddesquamationcausedbythejetof ignition,thesemi-closedbombwasusedtosimulatethestageofrapiddepressurizationafterbase bleedprojectileflightoutofthenozzle.Theserialimagesofignitionandcombustionofbasebleed propellantgrainwererecordedbymeansofhighspeedvideosystem.Themathematicmodelofcombustionofbasebleedpropellantinthesemi- closedbombwasbuilt.Thechangesofaveragepressure, massflowrateandcombustiontimefordifferentqualityoftotalfragmentswerecalculatedandanalyzed. Thestudyresultsareasfollows:Thephenomenonofencroachmentanddesquamationhappen atinitialstagesofignition;Thefragmentsaredesquamatedfromthepartofbasebleedpropellant grainnotbeingignited;Theeffectofencroachmentanddesquamationiscausedbytheencroachment andimpactofignitionjet;Themassofallfragmentsis(7-9)percentoftheinitialmassofthebase bleedpropellant;Theactionofencroachmentanddesquamationaffectsseriouslytheconsistenciesof ignitionofigniterandcombustionofbasebleedpropellantgrain.Thecalculationresultsagreewell withtheexperimentalresults.
2010, 30(6): 664-668.
doi: 10.11883/1001-1455(2010)06-0664-05
Abstract:
Aseriesofexperimentswereconductedtoinvestigatethesynchronyofthemulti-pointring initiatorappliedtoashapedchargeandthepenetrationcapabilityoftheshapedchargeswiththemultipointringinitiatorsintoreinforcedconcr tetargets.Theoutputsynchronyofallpointsofthemultipointringinitiatorwasmeasuredbyusingthehigh- speedphotographyandfiberprobetechnique.Itis showedthattheoutputsynchronyofallpointsisgoodandthelongesttimedifferenceislessthan 0.1s.Theshapedchargeswereinitiatedtopenetrateintoreinforcedconcretetargetsbyapplyingthe multi-pointringinitiatorsandthecentralpointinitiation,respectively.Comparisonoftheexperimentalresultsshowsthatthemulti- pointringinitiatorscanimprovemarkedlythepenetrationcapability oftheshapedcharges.
Aseriesofexperimentswereconductedtoinvestigatethesynchronyofthemulti-pointring initiatorappliedtoashapedchargeandthepenetrationcapabilityoftheshapedchargeswiththemultipointringinitiatorsintoreinforcedconcr tetargets.Theoutputsynchronyofallpointsofthemultipointringinitiatorwasmeasuredbyusingthehigh- speedphotographyandfiberprobetechnique.Itis showedthattheoutputsynchronyofallpointsisgoodandthelongesttimedifferenceislessthan 0.1s.Theshapedchargeswereinitiatedtopenetrateintoreinforcedconcretetargetsbyapplyingthe multi-pointringinitiatorsandthecentralpointinitiation,respectively.Comparisonoftheexperimentalresultsshowsthatthemulti- pointringinitiatorscanimprovemarkedlythepenetrationcapability oftheshapedcharges.
2010, 30(6): 669-672.
doi: 10.11883/1001-1455(2010)06-0669-04
Abstract:
Theaggregationformationofa20-nm-sizenanometeraluminumoxideparticleissimulated bythefastcoagulationdynamicsinthecolloidtheory.Itsgrowthtimeis0.11s,thetimeisless than1.0swhichismaximumtimeofchemicalreactionofconventionaldetonation.Sothecalculationresultprovesthatthenanometeraluminumoxideparticlesactuallygenerateinthechemicalreactionzoneofdetonation. Itisconsistentwiththeexperimentalconclusion.Theparametersofdetonationcanchangethelengthofthechemicalreactionzoneaccordingtothemechanicsofdetonationreaction. Sothegrowthtimeofnanometeraluminumoxideinthechemicalreactionzonecanbecontrolled byartificiallychangingtheparametersofdetonation.Inthiswaythesizeofthenanometeraluminum oxideparticlecanbecontrolled.
Theaggregationformationofa20-nm-sizenanometeraluminumoxideparticleissimulated bythefastcoagulationdynamicsinthecolloidtheory.Itsgrowthtimeis0.11s,thetimeisless than1.0swhichismaximumtimeofchemicalreactionofconventionaldetonation.Sothecalculationresultprovesthatthenanometeraluminumoxideparticlesactuallygenerateinthechemicalreactionzoneofdetonation. Itisconsistentwiththeexperimentalconclusion.Theparametersofdetonationcanchangethelengthofthechemicalreactionzoneaccordingtothemechanicsofdetonationreaction. Sothegrowthtimeofnanometeraluminumoxideinthechemicalreactionzonecanbecontrolled byartificiallychangingtheparametersofdetonation.Inthiswaythesizeofthenanometeraluminum oxideparticlecanbecontrolled.
