2013 Vol. 33, No. 2
column
Display Method:
2013, 33(2): 113-119.
doi: 10.11883/1001-1455(2013)02-0113-07
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Abstract:
Toexploretheeffectsoftheinitialdefectsonthefragmentationprocessesofmaterialsat highstrainrates,anexplicitFEMcodewasusedtosimulatethedynamicfragmentationprocessesof thinelastic-plasticbarsundergoinguniformhighstrain-ratetensiledeformations.Thethinbarwas prescribedwithperiodically-distributedgeometricaldefects.Numericalsimulationsdisplaythatthe barswiththeinitialdefectsusuallybreakintopiecesearlierthanthosewithoutdefects.Forthethin barswiththeperiodically-distributeddefects,thereexistsastrain-rateregioninwhichthefragmentationprocessiscompletelycontrolledbythedefects. Thisfragmentationprocessiscalledthedefectcontrolledfragmentationprocess. Thespacingandthesizeofthedefectsalsoaffectthefragmentation processbymovingthestrain-rateregionofthedefect-controlledfragmentation.Theeffectsofthe combineddefectdistributionontheductilefragmentationprocesswerealsodiscussed.
Toexploretheeffectsoftheinitialdefectsonthefragmentationprocessesofmaterialsat highstrainrates,anexplicitFEMcodewasusedtosimulatethedynamicfragmentationprocessesof thinelastic-plasticbarsundergoinguniformhighstrain-ratetensiledeformations.Thethinbarwas prescribedwithperiodically-distributedgeometricaldefects.Numericalsimulationsdisplaythatthe barswiththeinitialdefectsusuallybreakintopiecesearlierthanthosewithoutdefects.Forthethin barswiththeperiodically-distributeddefects,thereexistsastrain-rateregioninwhichthefragmentationprocessiscompletelycontrolledbythedefects. Thisfragmentationprocessiscalledthedefectcontrolledfragmentationprocess. Thespacingandthesizeofthedefectsalsoaffectthefragmentation processbymovingthestrain-rateregionofthedefect-controlledfragmentation.Theeffectsofthe combineddefectdistributionontheductilefragmentationprocesswerealsodiscussed.
2013, 33(2): 120-125.
doi: 10.11883/1001-1455(2013)02-0120-06
Abstract:
Basedonthehydrodynamic-elastoplasticmodel,theequationswereestablishedtocharacterizetheimpactpropertiesoftheAlfoamsunderexplosiveloading, whichweretransformedintodiscreteLagrangedifferenceformsinuniformgrid. TheshockresponsesoftheAlfoamsinwaterandair werenumericallycalculatedbytheself-developedone-dimensionalcode,respectively.Thenumerical resultsareinagreementwiththetheoreticalsolutionsandtheexperimentalones.Underthesameexplosiveloading, thelowerthedensityoftheAlfoam,thelowerthepeakpressureinit.Andundera contactexplosiveloading,thepropertiesofthematerialssurroundingtheAlfoamcanmarkedlyaffect thepressureonitsouterside.WhenairisoutsidetheAlfoam,thepressureintheAlfoamadjacent toairtakesonadownwardtrend.WhenwaterisoutsidetheAlfoam,thecorrespondingpressure takesonanupwardtrend.
Basedonthehydrodynamic-elastoplasticmodel,theequationswereestablishedtocharacterizetheimpactpropertiesoftheAlfoamsunderexplosiveloading, whichweretransformedintodiscreteLagrangedifferenceformsinuniformgrid. TheshockresponsesoftheAlfoamsinwaterandair werenumericallycalculatedbytheself-developedone-dimensionalcode,respectively.Thenumerical resultsareinagreementwiththetheoreticalsolutionsandtheexperimentalones.Underthesameexplosiveloading, thelowerthedensityoftheAlfoam,thelowerthepeakpressureinit.Andundera contactexplosiveloading,thepropertiesofthematerialssurroundingtheAlfoamcanmarkedlyaffect thepressureonitsouterside.WhenairisoutsidetheAlfoam,thepressureintheAlfoamadjacent toairtakesonadownwardtrend.WhenwaterisoutsidetheAlfoam,thecorrespondingpressure takesonanupwardtrend.
2013, 33(2): 126-132.
doi: 10.11883/1001-1455(2013)02-0126-07
Abstract:
Twokindsoftypicalsoftrockmaterials,mudstoneandsandymudstone,werechosenasthe researchedobjectives.Andtheiruniaxialdynamiccompressivepropertiesweretestedbyusingasplit Hopkinsonpressurebarsystem.Theobtainedstress-straincurvestakeoncomplexdynamiccharacteristicssuchasdistinctstrainhardeningandplasticfloweffects. Withaviewtotheaboveexperimentalresults, aviscoelasticstatisticaldamagemodelwasproposedbasedontheZhu-Wang-Tangmodel byconsideringtheinfluencesofdefectsinsoftrockmaterials.Theproposedmodelwasmadeupof twoMaxwellelementsandonestatisticaldamageelementinparallelconnection,inwhichthetwo Maxwellelementswithdifferentrelaxingtimesreflectingtheviscoelasticresponsesofsoftrockmaterialsatlowandhighstrainrates, respectively,andthestatisticaldamageelementtakingtheplaceof thenonlinearspringintheZhu-Wang-Tangmodel.Theexperimentaldatawerefittedtotheproposed model.Thefittedstress-traincurvesatdifferentstrainratesareinagreementwiththeexperimental ones
Twokindsoftypicalsoftrockmaterials,mudstoneandsandymudstone,werechosenasthe researchedobjectives.Andtheiruniaxialdynamiccompressivepropertiesweretestedbyusingasplit Hopkinsonpressurebarsystem.Theobtainedstress-straincurvestakeoncomplexdynamiccharacteristicssuchasdistinctstrainhardeningandplasticfloweffects. Withaviewtotheaboveexperimentalresults, aviscoelasticstatisticaldamagemodelwasproposedbasedontheZhu-Wang-Tangmodel byconsideringtheinfluencesofdefectsinsoftrockmaterials.Theproposedmodelwasmadeupof twoMaxwellelementsandonestatisticaldamageelementinparallelconnection,inwhichthetwo Maxwellelementswithdifferentrelaxingtimesreflectingtheviscoelasticresponsesofsoftrockmaterialsatlowandhighstrainrates, respectively,andthestatisticaldamageelementtakingtheplaceof thenonlinearspringintheZhu-Wang-Tangmodel.Theexperimentaldatawerefittedtotheproposed model.Thefittedstress-traincurvesatdifferentstrainratesareinagreementwiththeexperimental ones
2013, 33(2): 133-139.
doi: 10.11883/1001-1455(2013)02-0133-07
Abstract:
Thediscontinuoussmoothedparticlehydrodynamics(DSPH)methodwasdiscussedabout itssensitivitytotheparticleuniformityneartheboundary.Andthereasonsforthehighcalculation precisionbytheDSPH methodwereanalyzedbydeducingitsformulasfromtheexistentdiscontinuous SPHformulas.Byusingamodelforonerigidbodyimpactinganother,theDSPH methodwasapplied tophysicalproblemstocalculatethecorrespondingdensity,strainrateandenergy.Theinfluencesof theDSPH methodonthecalculatedresultswereexplored.
Thediscontinuoussmoothedparticlehydrodynamics(DSPH)methodwasdiscussedabout itssensitivitytotheparticleuniformityneartheboundary.Andthereasonsforthehighcalculation precisionbytheDSPH methodwereanalyzedbydeducingitsformulasfromtheexistentdiscontinuous SPHformulas.Byusingamodelforonerigidbodyimpactinganother,theDSPH methodwasapplied tophysicalproblemstocalculatethecorrespondingdensity,strainrateandenergy.Theinfluencesof theDSPH methodonthecalculatedresultswereexplored.
2013, 33(2): 140-147.
doi: 10.11883/1001-1455(2013)02-0140-08
Abstract:
Aimedtothepoormatchofthetraditionalwaveletpackettransform withthemeasured blastingvibrationsignalinthechoiceofwaveletbase,amethodwasproposedfortheconstructionof secondgenerationwaveletsbasedoninterpolationsubdivision.Andthefrequencyaliasresultedbydot interlacedsamplingwasovercomebyusinganalgorithm withfrequencyshift.Throughmulti-resolutiondecompositionofmeasuredsignals, energydistributionineveryfrequencybandwasobtained,by whichthedistributionfeaturesoftheblastingseismicsignalswereanalyzed.Analysisresultsshow thatthealgorithmfortheSGWPtransformcanreflecttheenergydistributionoftheblastingseismic signalsanditisaneffectiveapproachtoestimatingthestructuresafetyunderblastingvibrationconditions
Aimedtothepoormatchofthetraditionalwaveletpackettransform withthemeasured blastingvibrationsignalinthechoiceofwaveletbase,amethodwasproposedfortheconstructionof secondgenerationwaveletsbasedoninterpolationsubdivision.Andthefrequencyaliasresultedbydot interlacedsamplingwasovercomebyusinganalgorithm withfrequencyshift.Throughmulti-resolutiondecompositionofmeasuredsignals, energydistributionineveryfrequencybandwasobtained,by whichthedistributionfeaturesoftheblastingseismicsignalswereanalyzed.Analysisresultsshow thatthealgorithmfortheSGWPtransformcanreflecttheenergydistributionoftheblastingseismic signalsanditisaneffectiveapproachtoestimatingthestructuresafetyunderblastingvibrationconditions
2013, 33(2): 148-155.
doi: 10.11883/1001-1455(2013)02-0148-08
Abstract:
Basedonthecoldenergymixturetheory,theequationsofstateweregivenforthecompactionmultifunctionalenergeticstructuralmaterials( MESMs)undershockcompressionbyusingthe Hugoniotrelationsofthecomponents.AndcombiningtheabovemethodandtheWu-Jingmodel,the equationsofstatewereproposedfortheporousMESMsundershockcompressionalongtheisobaric paths.Toverifytheaccuracyofthecalculations,theHugoniotrelationswerecalculatedforthetypicalmetalparticlemixture( W/Cu)andthetypicalMESMs(Al/Ni,Ni/TiandAl/Fe2O3/epoxy),respectively. Thetheoreticalcalculationsagreewellwiththecorrespondingexperimentalresults.The shockcompressioncharacteristicsoftheMESMscanbeevidentlyinfluencedbytheirporositiesand theproportionsofthecomponentsinthem.
Basedonthecoldenergymixturetheory,theequationsofstateweregivenforthecompactionmultifunctionalenergeticstructuralmaterials( MESMs)undershockcompressionbyusingthe Hugoniotrelationsofthecomponents.AndcombiningtheabovemethodandtheWu-Jingmodel,the equationsofstatewereproposedfortheporousMESMsundershockcompressionalongtheisobaric paths.Toverifytheaccuracyofthecalculations,theHugoniotrelationswerecalculatedforthetypicalmetalparticlemixture( W/Cu)andthetypicalMESMs(Al/Ni,Ni/TiandAl/Fe2O3/epoxy),respectively. Thetheoreticalcalculationsagreewellwiththecorrespondingexperimentalresults.The shockcompressioncharacteristicsoftheMESMscanbeevidentlyinfluencedbytheirporositiesand theproportionsofthecomponentsinthem.
2013, 33(2): 156-162.
doi: 10.11883/1001-1455(2013)02-0156-07
Abstract:
Two-dimensional(2D)plain-wovenC/SiCcompositeplatesandduralumin (LY12)plates wereimpactedbymylar-filmflyerplateswhichwereloadedbyanelectricalgunto3.4-9.5m/s,respectively. Thefreeinterfacialvelocitiesoftheexperimentalplates were measured withalaser Dopplervelocimeterandtheimpact-induceddebriscloudswerecollectedwithpreparedfoamplates. Andthedamageareasoftheexperimentalplateswereinspectedbyusinganultrasonicscanningsystem. Basedontheaboveexperimentalresults,themechanicalresponsesofthe2Dplain-wovenC/SiC compositesunderhypervelocityimpactwereanalyzed.Theaboveexperimentalresultsshowthatwith theincreaseoftheimpactintensity,thefreeinterfacialvelocitiesofthe2Dplain-wovenC/SiCcompositeplatesincrease, thelocaldamageareasincrease,andthedebrisclouds-affectedregionsinthe preparedfoamplatesincrease.AndcomparedwiththeLY12platessubjectedtotheimpactofthe sameintensity,theintensitiesofthedebriscloudsfromthe2Dplain-wovenC/SiCcompositeplates arelower,theiraffectingregionsinthefoamplatesarelarger,andtheareicimpactenergiesarelower. Sothe2Dplain-wovenC/SiCcompositescanmarkedlydecreasethedamagewhichwillbesuffered byprotectedobjectsanditcanbeusedasanidealprotective materialinspacedebrisprotection shields.
Two-dimensional(2D)plain-wovenC/SiCcompositeplatesandduralumin (LY12)plates wereimpactedbymylar-filmflyerplateswhichwereloadedbyanelectricalgunto3.4-9.5m/s,respectively. Thefreeinterfacialvelocitiesoftheexperimentalplates were measured withalaser Dopplervelocimeterandtheimpact-induceddebriscloudswerecollectedwithpreparedfoamplates. Andthedamageareasoftheexperimentalplateswereinspectedbyusinganultrasonicscanningsystem. Basedontheaboveexperimentalresults,themechanicalresponsesofthe2Dplain-wovenC/SiC compositesunderhypervelocityimpactwereanalyzed.Theaboveexperimentalresultsshowthatwith theincreaseoftheimpactintensity,thefreeinterfacialvelocitiesofthe2Dplain-wovenC/SiCcompositeplatesincrease, thelocaldamageareasincrease,andthedebrisclouds-affectedregionsinthe preparedfoamplatesincrease.AndcomparedwiththeLY12platessubjectedtotheimpactofthe sameintensity,theintensitiesofthedebriscloudsfromthe2Dplain-wovenC/SiCcompositeplates arelower,theiraffectingregionsinthefoamplatesarelarger,andtheareicimpactenergiesarelower. Sothe2Dplain-wovenC/SiCcompositescanmarkedlydecreasethedamagewhichwillbesuffered byprotectedobjectsanditcanbeusedasanidealprotective materialinspacedebrisprotection shields.
2013, 33(2): 163-168.
doi: 10.11883/1001-1455(2013)02-0163-06
Abstract:
Basedonthetwo-dimensionalringsystem,acomputationalmodelwasdevelopedfordensity- gradedcircularhoneycomb materialsbychangingthewallthicknessesoftherings.Andfurther discussionwascarriedoutfortheinfluencesofthedensitygradientvariationontheenergy-absorption performancesofthedensity-gradedhoneycombmaterialsimpactedbytherigidplateatdifferentvelocities. Theresultsshowthatforthehoneycombmaterialwiththerelativedensitydecreasingfromthe impactendtothefixedend,underahigh-velocityimpact,thehigherthedensitygradient,themore theenergyabsorbedperunitmass.
Basedonthetwo-dimensionalringsystem,acomputationalmodelwasdevelopedfordensity- gradedcircularhoneycomb materialsbychangingthewallthicknessesoftherings.Andfurther discussionwascarriedoutfortheinfluencesofthedensitygradientvariationontheenergy-absorption performancesofthedensity-gradedhoneycombmaterialsimpactedbytherigidplateatdifferentvelocities. Theresultsshowthatforthehoneycombmaterialwiththerelativedensitydecreasingfromthe impactendtothefixedend,underahigh-velocityimpact,thehigherthedensitygradient,themore theenergyabsorbedperunitmass.
2013, 33(2): 169-174.
doi: 10.11883/1001-1455(2013)02-0169-06
Abstract:
Penetrationexperimentswereconductedbylaunchinghemispherical-nosesolidsteelprojectilesintothinconcretetargets. Basedontheaboveexperiments,someproblemscorrelatedwiththe theoreticalmodelandnumericalmodelwerediscussed.Inthepenetrationexperiments,thestrain,the accelerationandthedeforminghistoryofthetargetsweremeasuredbystraingauges,accelerometers andahigh-peedcamera,respectively.Experimentalresultsshowthatthetargetboundariesaremain factorsaffectingthestresswavereflectionandthepenetrationresponsesinthetargets.Andthepenetrationcanbedividedintothefollowingthreestages: thestresswavepropagationmustbeconsidered intheinitialstage;thestresswavepropagationandthefragmentflyingarethemainresponsesinthe secondstage;andthestresswavepropagationdisappearsandthefragmentsflyingbecomesthemain responseinthethirdstage.
Penetrationexperimentswereconductedbylaunchinghemispherical-nosesolidsteelprojectilesintothinconcretetargets. Basedontheaboveexperiments,someproblemscorrelatedwiththe theoreticalmodelandnumericalmodelwerediscussed.Inthepenetrationexperiments,thestrain,the accelerationandthedeforminghistoryofthetargetsweremeasuredbystraingauges,accelerometers andahigh-peedcamera,respectively.Experimentalresultsshowthatthetargetboundariesaremain factorsaffectingthestresswavereflectionandthepenetrationresponsesinthetargets.Andthepenetrationcanbedividedintothefollowingthreestages: thestresswavepropagationmustbeconsidered intheinitialstage;thestresswavepropagationandthefragmentflyingarethemainresponsesinthe secondstage;andthestresswavepropagationdisappearsandthefragmentsflyingbecomesthemain responseinthethirdstage.
2013, 33(2): 175-180.
doi: 10.11883/1001-1455(2013)02-0175-06
Abstract:
Toinvestigatetheshockwavepropagationandthebubblemotionofunderwaterexplosion fromabottomcharge,principleexperimentsofunderwaterexplosionwereconductedinawatertank. High-speedcameraswereusedtocapturethegasbubbleformationandcollapse,andpressuretransducerstorecordpressuretimehistoriesatseverallocations. Comparedwiththeloadingcharacteristics ofthefree-fieldunderwaterexplosion,someconclusionswereobtained.Underwaterexplosionfroma bottomchargehasaseriescomplexloadingeffects:shockwavereflection,bubblesharpexpansion, bubblejetting,andsoon.Duetothebottominfluence,thebubbleshapeandbubblemigrationare significantlydifferentfromthoseofthefree-fieldunderwaterexplosion,andtheshockwavepropagationtakesonanexponentialdecay, buthasnotthesecondpressurewave.Forthepointsnearthebottomofthewatertank, theincidentwavecanbestrengthenedbytheshockwavereflectedfromthe bottom.
Toinvestigatetheshockwavepropagationandthebubblemotionofunderwaterexplosion fromabottomcharge,principleexperimentsofunderwaterexplosionwereconductedinawatertank. High-speedcameraswereusedtocapturethegasbubbleformationandcollapse,andpressuretransducerstorecordpressuretimehistoriesatseverallocations. Comparedwiththeloadingcharacteristics ofthefree-fieldunderwaterexplosion,someconclusionswereobtained.Underwaterexplosionfroma bottomchargehasaseriescomplexloadingeffects:shockwavereflection,bubblesharpexpansion, bubblejetting,andsoon.Duetothebottominfluence,thebubbleshapeandbubblemigrationare significantlydifferentfromthoseofthefree-fieldunderwaterexplosion,andtheshockwavepropagationtakesonanexponentialdecay, buthasnotthesecondpressurewave.Forthepointsnearthebottomofthewatertank, theincidentwavecanbestrengthenedbytheshockwavereflectedfromthe bottom.
2013, 33(2): 181-185.
doi: 10.11883/1001-1455(2013)02-0181-05
Abstract:
Abstract:Basedontheminimum mean-squareerrorapproach,acomputationalmethodwasproposed forlocatingthepositionsofunderwaterexplosionsources.Theverificationexperimentsshowthatthe proposedlocationmethodcanmeetwiththetestrequirementswhenthequantityoftheeffectivedata observedbythepressuresensorsisnotlessthanfour.Satisfactorycomputationalresultscanstillbe obtainedeveniftheaccuraciesofseveraltestdataareweak.Theinfluencingfactorsofthecomputationalerrorwerediscussedasfollows: veracitiesoftestdata,positionturbulenceoftestpoints,accuraciesofmodelparametersandquantityoftestpoints. Consequently,somesuggestionswereputforwardaboutthelocationcomputationforunderwaterexplosionsources.
Abstract:Basedontheminimum mean-squareerrorapproach,acomputationalmethodwasproposed forlocatingthepositionsofunderwaterexplosionsources.Theverificationexperimentsshowthatthe proposedlocationmethodcanmeetwiththetestrequirementswhenthequantityoftheeffectivedata observedbythepressuresensorsisnotlessthanfour.Satisfactorycomputationalresultscanstillbe obtainedeveniftheaccuraciesofseveraltestdataareweak.Theinfluencingfactorsofthecomputationalerrorwerediscussedasfollows: veracitiesoftestdata,positionturbulenceoftestpoints,accuraciesofmodelparametersandquantityoftestpoints. Consequently,somesuggestionswereputforwardaboutthelocationcomputationforunderwaterexplosionsources.
2013, 33(2): 186-193.
doi: 10.11883/1001-1455(2013)02-0186-08
Abstract:
Basedonthe60-mm-diameterexplosively-formedprojectile(EFP)warheadwithanarc-cone liner,amultipleexplosively-formedprojectile(MEFP)warheadwasdesignedbyfixinganejectable cross-shapedreseauinaproperplaceinfrontofthelinerasthecuttingdevice.Andthearmor-piercing effectofthedesignedMEFPwarheadwasinvestigatedbycarryingoutstatic-explosiontests.Theresultsindicatethatthedesignedwarheadcanbecutinto5EFPswhichhaveacertainmassanddirection, andcanpenetratethrougha6-mm-thick45steeltarget.Itiseffectivetoincreasedamageelementsanddamagearea. TheprocessoftheMEFPspenetratingthroughthe45steeltargetswasnumericallyanalyzedbyusingLS- DYNA3D.TheballisticlimitingvelocityformulaoftheEFPswith differentsizesandstructureswereobtainedbyprocessingthesimulateddataofthecenterEFPpenetratingthroughthe45steeltarget
Basedonthe60-mm-diameterexplosively-formedprojectile(EFP)warheadwithanarc-cone liner,amultipleexplosively-formedprojectile(MEFP)warheadwasdesignedbyfixinganejectable cross-shapedreseauinaproperplaceinfrontofthelinerasthecuttingdevice.Andthearmor-piercing effectofthedesignedMEFPwarheadwasinvestigatedbycarryingoutstatic-explosiontests.Theresultsindicatethatthedesignedwarheadcanbecutinto5EFPswhichhaveacertainmassanddirection, andcanpenetratethrougha6-mm-thick45steeltarget.Itiseffectivetoincreasedamageelementsanddamagearea. TheprocessoftheMEFPspenetratingthroughthe45steeltargetswasnumericallyanalyzedbyusingLS- DYNA3D.TheballisticlimitingvelocityformulaoftheEFPswith differentsizesandstructureswereobtainedbyprocessingthesimulateddataofthecenterEFPpenetratingthroughthe45steeltarget
2013, 33(2): 194-199.
doi: 10.11883/1001-1455(2013)02-0194-06
Abstract:
Byadoptingthestoragetesttechniquesunderbadenvironments,ashockwaverecordersystem wasdesignedwithMCUandCPLDasthemaincontrolchips.Therecordersystemhasinsideand outsidetriggerfunctions,inwhichtheopticalfibersareusedtotransmitthetriggeredsignals.And thehighanti-interferenceabilityofthetriggercircuitscanensuretherecordersystemhavethesame timestandardsandbetriggeredreliably.Theshocktubecalibrationexperimentandthewarshipexperimentwereconducted. Andtheshockwavesignalswererecordedsuccessfullybytherecordersystem. Sothedesignedrecordersystemhasgoodpracticabilityandreliability.
Byadoptingthestoragetesttechniquesunderbadenvironments,ashockwaverecordersystem wasdesignedwithMCUandCPLDasthemaincontrolchips.Therecordersystemhasinsideand outsidetriggerfunctions,inwhichtheopticalfibersareusedtotransmitthetriggeredsignals.And thehighanti-interferenceabilityofthetriggercircuitscanensuretherecordersystemhavethesame timestandardsandbetriggeredreliably.Theshocktubecalibrationexperimentandthewarshipexperimentwereconducted. Andtheshockwavesignalswererecordedsuccessfullybytherecordersystem. Sothedesignedrecordersystemhasgoodpracticabilityandreliability.
2013, 33(2): 200-206.
doi: 10.11883/1001-1455(2013)02-0200-07
Abstract:
Aimedtothesecurityestimationofcylindricalexplosionvessels,theradialdistortionatthe centersectionofthevesselwasnumericallycalculated.Whentheinitialparametersaresetwithrandomerrors, thefinalsimulationresultschangeobviously.Someessentialparametersaresampledby theMonte-Carlomethod,sothattheuncertaintyoftheseparameterscanbeconsideredinthecalculationprocess, andtheresultsactuallyarethesamplesoftheradialdistortionofthevessel.Basedon thestatisticalanalysisofthesamples,theconfidenceintervalestimationmethodforthesecurityprobabilityofcylindricalexplosionvesselswasproposed. Thevalidityandaccuracyofthemethodwerealsoillustratedbyexamples.
Aimedtothesecurityestimationofcylindricalexplosionvessels,theradialdistortionatthe centersectionofthevesselwasnumericallycalculated.Whentheinitialparametersaresetwithrandomerrors, thefinalsimulationresultschangeobviously.Someessentialparametersaresampledby theMonte-Carlomethod,sothattheuncertaintyoftheseparameterscanbeconsideredinthecalculationprocess, andtheresultsactuallyarethesamplesoftheradialdistortionofthevessel.Basedon thestatisticalanalysisofthesamples,theconfidenceintervalestimationmethodforthesecurityprobabilityofcylindricalexplosionvesselswasproposed. Thevalidityandaccuracyofthemethodwerealsoillustratedbyexamples.
2013, 33(2): 207-211.
doi: 10.11883/1001-1455(2013)02-0207-05
Abstract:
Theappearanceofinsensitiveammunitionhascreatednewrequirementsfortheboosterpelletsofthedetonationtrain. Traditionalcylindricalboosterpelletshavemuchdifficultyinmeetinginsensitiveammunitionsdemandofreliabledetonation. Thedesigntheoryofhigh-effect-boostercharge structure,initiationprocess,initiationforce,andthehighoutputoflittlequantity,offerscientific supportforthedevelopmentofinsensitiveammunitionintechnique.So,aspecialboosterpelletwas designedthroughthecombineduseofshockinitiationtheory,effectivechargetheory,shapedcharge effectaswellascornereffecttheory.Theinitiationcapacityofthespecialboosterpelletwasstudied byusingthevaried-compositionmethodandaxialsteeldentmethodofmaincharge.Theresultsshow thattheinitiationcapacityofthespecialboosterpelletisbetterthanthatofthecylindricalboosterpellet. Theinitiationcapacityofthespecialboosterpelletisaffectedbytheareaeffectcoefficientandincreaseswiththeincreaseoftheareaeffectco fficient.Thespecialboosterpelletcanmeetthedemands oftheinsensitiveammunition.
Theappearanceofinsensitiveammunitionhascreatednewrequirementsfortheboosterpelletsofthedetonationtrain. Traditionalcylindricalboosterpelletshavemuchdifficultyinmeetinginsensitiveammunitionsdemandofreliabledetonation. Thedesigntheoryofhigh-effect-boostercharge structure,initiationprocess,initiationforce,andthehighoutputoflittlequantity,offerscientific supportforthedevelopmentofinsensitiveammunitionintechnique.So,aspecialboosterpelletwas designedthroughthecombineduseofshockinitiationtheory,effectivechargetheory,shapedcharge effectaswellascornereffecttheory.Theinitiationcapacityofthespecialboosterpelletwasstudied byusingthevaried-compositionmethodandaxialsteeldentmethodofmaincharge.Theresultsshow thattheinitiationcapacityofthespecialboosterpelletisbetterthanthatofthecylindricalboosterpellet. Theinitiationcapacityofthespecialboosterpelletisaffectedbytheareaeffectcoefficientandincreaseswiththeincreaseoftheareaeffectco fficient.Thespecialboosterpelletcanmeetthedemands oftheinsensitiveammunition.
2013, 33(2): 212-216.
doi: 10.11883/1001-1455(2013)02-0212-05
Abstract:
Tostudythedischargecharacteristicsofferroelectricceramicsashighpowerpulsesupplyof miniatureelectromagneticpulsebombs,thenumericalalgorithmoftheshockwaveontheferroelectricceramicsimpactedbyanexplosive- drivenflyerwasbroughtforward.Theimpactloadsofdifferentcharginglengthswerecalculated. ThedepolarizationdischargemodelforPZT95/5loadedbya highvoltageenergystoragecapacitorwasestablished.Theexperimentaldeviceforthedepolarization dischargeofPZT95/5wasdesigned.Theexperimentalresultsshowthat5mmcharginglengthcan meetthetransitionpressureofferroelectricceramics.Theenergystoragecapacitorenlargesthedischargepulsewidthto20swhentheelectricalparametersoftheloadare0.2and18H. Thedepolarizationdischargeenergyincreaseswiththegrowthofthenumberoftheferroelectricceramicsin parallelconnection.Thedischarginglossrateisabout15%.
Tostudythedischargecharacteristicsofferroelectricceramicsashighpowerpulsesupplyof miniatureelectromagneticpulsebombs,thenumericalalgorithmoftheshockwaveontheferroelectricceramicsimpactedbyanexplosive- drivenflyerwasbroughtforward.Theimpactloadsofdifferentcharginglengthswerecalculated. ThedepolarizationdischargemodelforPZT95/5loadedbya highvoltageenergystoragecapacitorwasestablished.Theexperimentaldeviceforthedepolarization dischargeofPZT95/5wasdesigned.Theexperimentalresultsshowthat5mmcharginglengthcan meetthetransitionpressureofferroelectricceramics.Theenergystoragecapacitorenlargesthedischargepulsewidthto20swhentheelectricalparametersoftheloadare0.2and18H. Thedepolarizationdischargeenergyincreaseswiththegrowthofthenumberoftheferroelectricceramicsin parallelconnection.Thedischarginglossrateisabout15%.
2013, 33(2): 217-221.
doi: 10.11883/1001-1455(2013)02-0217-04
Abstract:
Atwo-dimensionalLagrangianelastic-plastichydrodynamicfiniteelementcodenamedLTZ- 2Dwasusedtonumericallyexploretheinfluencesoftheaggregatestructuresonthepenetration processesoftheconcretetargetsimpactedbytheprojectilesaswellasthecorrespondingtargetdamage. Andthedimensionsoftheaggregatestructureswereconsideredtobemuchlessthanthoseofthe projectiles.Comparedwithevenconcretetargets,forathinaggregateconcreteplate,whentheimpactvelocityisrelativelylow, theaggregatestructurewillresisttheprojectile,butwhentheimpact velocityishighenough,theresidualvelocitywillbehigherduetothedamageareaincreaseintheback oftheconcreteplate.However,forthickconcretetargets,theinfluencesoftheaggregatestructures onthepenetratingprocesscanbeignored.
Atwo-dimensionalLagrangianelastic-plastichydrodynamicfiniteelementcodenamedLTZ- 2Dwasusedtonumericallyexploretheinfluencesoftheaggregatestructuresonthepenetration processesoftheconcretetargetsimpactedbytheprojectilesaswellasthecorrespondingtargetdamage. Andthedimensionsoftheaggregatestructureswereconsideredtobemuchlessthanthoseofthe projectiles.Comparedwithevenconcretetargets,forathinaggregateconcreteplate,whentheimpactvelocityisrelativelylow, theaggregatestructurewillresisttheprojectile,butwhentheimpact velocityishighenough,theresidualvelocitywillbehigherduetothedamageareaincreaseintheback oftheconcreteplate.However,forthickconcretetargets,theinfluencesoftheaggregatestructures onthepenetratingprocesscanbeignored.
2013, 33(2): 221-224.
doi: 10.11883/1001-1455(2013)02-0221-04
Abstract:
SevenkindsofRDX-basedhighexplosivesampleswithdifferentdensitieswerepreparedto studytheinfluencesofexplosivechargedensitiesoncook-offresponse.Theslowcook-offexperiments wereconductedbyusingthecook-offbombswiththelength-diameterratioofabout1.2attherateof (10.2)℃/min.Theresultsindicatethatapressureburstoccursinthetestsat94.5%theoretical maximumdensityandadeflagrationoccursat70%theoreticalmaximumdensity.Thetestsundergoa deflagrationtodetonationtransition (DDT)atabout80%theoreticalmaximumdensityandtheresponseisviolent. Theresultswillsupplyahelpforreducingthehotcook-offvulnerabilityofammunitionaswellasthestudyontheslowcook- offmechanism.
SevenkindsofRDX-basedhighexplosivesampleswithdifferentdensitieswerepreparedto studytheinfluencesofexplosivechargedensitiesoncook-offresponse.Theslowcook-offexperiments wereconductedbyusingthecook-offbombswiththelength-diameterratioofabout1.2attherateof (10.2)℃/min.Theresultsindicatethatapressureburstoccursinthetestsat94.5%theoretical maximumdensityandadeflagrationoccursat70%theoreticalmaximumdensity.Thetestsundergoa deflagrationtodetonationtransition (DDT)atabout80%theoreticalmaximumdensityandtheresponseisviolent. Theresultswillsupplyahelpforreducingthehotcook-offvulnerabilityofammunitionaswellasthestudyontheslowcook- offmechanism.
