2011 Vol. 31, No. 3

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Article
In-planedynamiccrushingoffunctionallylayeredmetalhoneycombs
LIU Ying, HE Zhang-quan, WU He-xiang, ZHANG Xin-chun
2011, 31(3): 225-331. doi: 10.11883/1001-1455(2011)03-0225-07
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Abstract:
Afunctionallylayeredhoneycombmodelisproposedtocontrolthedynamicenergyabsorptionofferedbyuniformhoneycombs. Thein-planedynamicresponsesarecontrolledbythevariation ofthecellradius.Thenumericalresultsshowthatthroughtheproperchoiceofthegradientcoefficient, theinitialforcepeakcanbereducedsignificantly,andtheenergyabsorptioncanbecontrolled. Moreover,thevaluesforthetransmittedstressesintotheprotectedstructurescanbegreatlyreduced. Thesefindingscanprovidevaluablesuggestionsinthemulti-objectiveoptimaldesignofhoneycombs.
Luminousfluxmethodformeasuringshearstrain ofthespecimeninSHPSB
ZHAO Peng-duo, LU Fang-yun, CHEN Rong, LI Jun-ling, LIN Yu-liang, TAN Duo-wang
2011, 31(3): 232-236. doi: 10.11883/1001-1455(2011)03-0232-05
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Abstract:
AtechniquebasedonluminousfluxmethodwasappliedtomeasureshearstraininSHPSB (splitHopkinsonpressurebar)experiment.Theopticalsetupconsistedofthreemajorcomponents:a collimationlaser,aphotoelectricsensingapparatusandtwoopticalbaffles.Resultsfromavalidexperimentandanuncertaintyanalysisshowedthatitwaseffectiveandaccuratetogettheshearstrain ofthespecimen.Theshearstrainmeasuredbytheopticalapparatuswascomparedwiththetheoretic ones.Itwasfoundandanalyzedthatthemeasuredshearstrainwaslessthanthatofthetheoryinvalue
Parametricandnonlinearfeatureextractionofnuclearexplosions andearthquakesbasedonVolterraseries
HAN Shao-qing, LI Xi-hai, WU Hai-jun, LIU Dai-zhi
2011, 31(3): 237-242. doi: 10.11883/1001-1455(2011)03-0237-06
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Abstract:
ARMAparameterscanbeusedasfeaturesfordiscriminationbetweennuclearexplosions andearthquakes.Currentmethodsforfeatureextractionarelinearandonlytakesadvantageofthe second-orderstatistic,sotheclassificationaccuracyofisnothigh.Tosolvethisproblem,amethod forextractingnonlinearfeaturesofnuclearexplosionsandearthquakeswasproposedbasedonthechaoticfeatureofseismicwaves. Firstly,thephasespaceofseismicwaveswasreconstructed.Secondly, theadaptivepredictionmodelbasedonVolterraserieswasestablishedinthephasespace.Finally,the modelparametersweretakenasthefeaturesofseismicsamples.Intheclassificationexperimentofof nuclearexplosionsandearthquakes,nonlinearfeaturesobtainedbetterperformancethanlinearfeatures. Investigatedresultsshowthatthecombinationoflinear,nonlinearandhigher-orderstatistical informationiscriticalfortheclassificationofnuclearexplosionsandearthquakes.
AnewcoupledSPH-FEMalgorithmand itsapplicationtoimpactdynamics
ZHANG Zhi-chun, QIANG Hong-fu, GAO Wei-ran
2011, 31(3): 243-249. doi: 10.11883/1001-1455(2011)03-0243-07
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Abstract:
Thecouplingofsmoothedparticlehydrodynamics(SPH)withthefiniteelementmethod (FEM)ispresentedtomakefulluseofthesuperiorityofSPHindealingwithlargedeformationand thehighaccuracyofFEM.ThecoupledSPH-FEMalgorithmemploysSPHparticlesinthehigherdistortionregionsandfiniteelementsinthelowerdistortionregions. Inthecoupledinterface,SPHparticlesareattachedtofiniteelements. BackgroundparticlesareassignedinthepositionofFEnodes, andFEnodesareaddedtoSPHneighborlist.TheboundaryeffectofSPHisavoided,andthecontinuityoftheinterfaceisguaranteed. Theperforationofacylindricalsteelprojectileimpactingaplate targetissimulatedin3DusingthecoupledSPH-FEMalgorithm.TheJohnson-Cookmaterialmodel withdamageeffectandGrneisenequationofstateareemployedforthetarget,andthecomputedresultsshowgoodagreementwiththeexperimentaldata.
Waterjetphenomenainducedbytheinteractionbetween underwaterexplosionbubblesandwaterbottomboundaries
WANG Bin, ZHANG Yuan-ping, WANG Yan-ping
2011, 31(3): 250-255. doi: 10.11883/1001-1455(2011)03-0250-06
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Abstract:
TheKelvinimpulseprinciplewasappliedtoanalyzethemajorinfluencefactorsintheformationofthewaterjetbytheinteractionbetweenanunderw terexplosionbubbleandawaterbottom boundary.Andaseriesofexperimentswereconductedinawatertanktoinvestigatethewaterjet phenomenainducedbytheinteractionbetweenbubblesandahorizontallyplacedsteelplate.Thedistancebetweentheexplosiveandthesteelplatewaschangedwiththedifferentexperimentalconditions. Theoscillationpicturesofthewaterjetswerecapturedbyahigh-speedcameraandthepulse pressuresofthebubbleswereobtainedbypressuresensorsatthepositionswiththedifferentdistances awayfromtheexplosionsource.Boththetheoreticalanalysisandtheexperimentalresultsshowthat theBjerknesforceincreasesmarkedlywiththedecreasingdistancebetweentheexplosiveandthesteel plate,andthecriticalcondition,fortheformationofthewaterjetbytheinteractionbetweenthebubbleandthehorizontallyplacedsteelplate, isthattheexplosiondistanceisshorterthanthemaximum bubbleradius.Andthewaterjethasadistinctorientationanditcanremarkablydamagethetarget.
Dynamicindentationexperimentbasedon thesplit-Hopkinsonpressurebarsystem
ZHANG Xin, HOU Bing, LI Yu-long
2011, 31(3): 256-262. doi: 10.11883/1001-1455(2011)03-0256-07
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Abstract:
Anewtechnologyfortestingdynamicpropertiesofmaterialswasproposedbydevelopingan experimentalsetupbasedonasplit-Hopkinsonpressurebarsystem.Theexperimentalsetupcanbe usedindynamicindentationexperimentstoobtaintheindentationdisplacementsofmaterialsandthe impactloadsufferedbythem.Tovalidatetheexperimentalsetup,theABAQUS/ExplicitFEcode wasusedtonumericallysimulatedynamicindentationexperiments.Dynamicindentationexperiments wereconductedonaluminumalloyLY12,puretitaniumandoxygen-freecopper.Thedynamicpropertiessuchasdynamichardnessandratesensitivitywereobtainedforthesethreekindsofmaterials. Thedynamicpropertiesobtainedbydynamicindentationexperimentsareconsistentwiththoseby otherexperimentalmethods.
Behaviorsofbubblejetsinducedbyunderwaterexplosion ofcylindricalchargesunderfree-fieldconditions
HUANG Chao, WANG Bin, ZHANG Yuan-ping
2011, 31(3): 263-267. doi: 10.11883/1001-1455(2011)03-0263-05
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Abstract:
UnderwaterexplosionexperimentswerecarriedoutforPETNcylindersinawatertankand elementarydataaboutbubblemotionsunderfree-fieldconditionswereobtainedbyusingthehighspeedphotographytechnology. Resultsshowthatthebubbledynamicsofcylindricalchargesdiffers fromthoseofsphericalones,andchargemountingmodesaffectmarkedlybubblebehaviors.Fora horizontallymountedcylindricalcharge,asymmetriccollapseisachievedduetotheasymmetricmotionofthebubbleinterface. Asaresult,anasymmetricjetisformedandthewidthofthejetvaries withthelength-diameterratioofthecharge.Ontheotherhand,foraverticallymountedcylindrical charge,asymmetricjetisgeneratedduetotheaxialsymmetricmotionofthebubbleinterface.Inthe caseofequal-weightcharges,thevelocityofthejetgeneratedbytheverticallymountedcylindrical chargeishigherthanthatgeneratedbythehorizontally-mountedone.
Athermo-viscoelasticrate-dependentconstitutiveequation forcementmortarwithdamage
TAO Jun-lin, LI Kui
2011, 31(3): 268-273. doi: 10.11883/1001-1455(2011)03-0268-06
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Abstract:
Basedona50-mm-diametersplitHopkinsonpressurebar(SHPB)systemandaself-developedconcrete- likematerialrapidheatingdevice,impactcompressiveexperimentswerecarriedout. Thestress-straincurvesatdifferenttemperatureandthreekindsofimpactvelocitieswereobtained. BasedontheZWTvisco-elasticconstitutivemodelanddamageevolutionofcementmortarfollowing Weibulldistribution,thedamagethermo-viscoelasticconstitutiveequationathighstrainrateswas proposed.Throughthenumericalfitting,theparametersoftheconstitutiveequationwereobtained. Comparisonsshowthatthemodelpredictionsagreewellwiththeexperimentresults.
Numericalanalysisofquasi-isentropiccompressionofRDX(210)crystal
ZHANG Hong-ping, LI Mu, ZHAO Jian-heng, SUN Cheng-wei, ZHU Wen-jun
2011, 31(3): 274-278. doi: 10.11883/1001-1455(2011)03-0274-05
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Abstract:
Aimedatquasi-isentropiccompressionexperiments,abackwardintegrationmodelwasproposedbyconsi- deringlinearelastic-plasticeffects.Thequasi-isentropiccompressionexperimentdata ofRDX(210)crystalfromtheZmachineofSandiaNationalLaboratorywerenumericallyanalyzed. ComparisonbetweenthenumericalresultsandthedatabyBaerM R,etaldisplaysthattheproposed backwardintegration modelcanbeusedtodescribethequasi-isentropiccompressionofRDX(210) crystal.AndthisintegrationmethodwasusedtocalculatetheinformationatanypositionintheRDX (210)sample,especiallyattheloadingsurface,stress-straincurvesandLagrangiansoundvelocities. Thequasi-isentropewasachievedbasedonthemathe-maticsearchprocessofparameters.
Identificationofdynamicconstitutiveparametersofahigh-strengthsteel andnumericalsimulation
XIE Heng, Lü Zhen-hua
2011, 31(3): 279-284. doi: 10.11883/1001-1455(2011)03-0279-06
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Abstract:
Theengineeringstress-engineeringstrainrelationsofN-1steelweremeasuredusingSHTB atdifferentstrainratesfrom10-3to103s-1.Theresultswereanalyzed,andtherate-hardeninglawof N-1steelwasdetermined.Thetruestressatthecenterofthefracturedcross-sectionwascalculated. Therelationbetweentruestrainandspecimensvaryingthicknesswithinthesmallestcross-section wasexplored,andthetruestrainatthecenterofthefracturedcross-sectionwasidentifiedwitha modifiedapproach.ThusthemodifiedJohnson-Cook (MJC)constitutivemodelparametersofN-1 steelwereidentified.Thebar-barimpacttensileexperimentswithrectangularcross-sectionspecimens werenumericallysimulatedtoverifytheproposedconstitutivemodelparameteridentificationmethod andsimulationmethod.Thesimulatedresultsaresatisfying.
Modelingandsimulationoflaser-inducedignition usingdetailedchemicalkinetics
TIAN Zhan-dong, ZHANG Zhen-yu, LU Fang-yun, ZHAOJian-heng
2011, 31(3): 285-289. doi: 10.11883/1001-1455(2011)03-0285-05
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Abstract:
Inordertoinvestigateignitioncharacteristicofenergeticmaterialsradiatedbylaser,agasphasereactionmodelwasestablishedusingdetailedchemicalkinetics. Inthemodel,45speciesand 232reactionstepswasusedtodescribegasphasemechanism.Thenthemodelwasusedformodeling theprocessoflaser-inducedignitionofRDX.Temperaturedistributionsinbothcondensedandgas phasewereobtainedtoanalysetheprocessofignitionofRDX.MoleFractionsofmainspecieswere presentedtoshowthechemicalreactionprocessinthegasphase.Thecalculatedignitiondelaytimes areconsistentwiththeresultsinliteratures.
Predictionmethodofthedirectgroundshockparametersofexplosion atdifferentburieddepthsinfreefieldoflimestone
ZHAO Hong-ling, HOU Ai-jun, TONG Huai-feng, WANG Ji-sheng
2011, 31(3): 290-294. doi: 10.11883/1001-1455(2011)03-0290-05
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Abstract:
Throughthefieldtests,thepropagationregularityofthedirectgroundshockproducedby theexplosionofconventionalchargeatdifferentburieddepthsinfreefieldoflimestonewasexplored. Thedirectgroundshockeffectofexplosionatdifferentburieddepthswasdescribedbytheprocessing engineeringmethodcalledtheburieddepthcoefficientofequivalentenergy.Theburieddepthcoefficientofequivalentenergyofstressandparticleaccelerationofexplosionatdifferentburieddepthsin limestonewereformulated,whichcouldbethepredictionformulaofthegroundshockparametersof explosionatdifferentburieddepthsinlimestonemediaaccordingtothescaleddistancechange.
Underwaterexplosioncalculationwithafieldseparationtechnique
GUO Jun, YANG Wen-shan, YAO Xiong-liang, ZAHNG A-man, REN Shao-fei
2011, 31(3): 295-299. doi: 10.11883/1001-1455(2011)03-0295-05
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Theunderwaterexplosionmechanismoffluid-structureinteractionwasexploredbasedon thespectralelement.Afieldseparationtechniquewasproposedtoavoidthedistortionphenomenonof thetotalfieldmodelproducedbythepropagationofincidentwaveinthefluidmesh.Andascatteredfieldnumericalmodelforunderwaterexplosionfluid- structurecouplingproblemswasestablishedby theoreticalderivation.Calculationresultsbyaself-developedcodeshowthatthescattered-fieldnumericalmodelisaneffectivesolutiontotheincident- wavedistortion,ithasahighercalculationaccuracythanthetotalfieldmodel, anditcanbeappliedtosolvefluid-solidcouplingproblemsduringunderwaterexplosion.
Experimentandnumericalsimulationforhighpressurecombustiblegasjet expansionprocessinabulk-loadedliquid
MANG Shan-shan, YU Yong-gang
2011, 31(3): 300-305. doi: 10.11883/1001-1455(2011)03-0300-06
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Abstract:
Inordertoinvestigatetheexpansioncharacteristicsofthehighpressurecombustiblegasjet inabulk-loadedliquidandtoexplorethecontrolmethodsforimproveingthejetstability,acylindrical four-stagestepped-wallchamberwasdesigned.Usingahigh-speedkinescopesystem,theexpansion andmixingprocessofthegasjetintheliquidwasobserved.Aseriesofphotosdescribingjetexpansionform wereobtained,theexpansionvelocityoftheTaylorcavitywasmeasuredandtheeffectsof thechamberwallshapeonthejetexpansionwerecompared.A2-Daxisymmetricgas-liquidtwo-phase turbulentflow modelwasdevelopedtosimulatethejetexpansionprocess.ThecalculatedjetexpansionshapeandexpansionvelocityoftheTaylorcavitywereconsistentwithexperimentalresults. Obtainedresultsshowthatvortexemergesatthechambersteps, whichinducesthejettoexpandradially thenrestrainsKelvin-Helmholtzinstability.Thestepped-wallchamberboundarycanimprovethejet stability.
Adamage-powerevaluationmethodoftheexplosive-involveddevice inaconfinedcontainerstoringliquid
GAO Hong-quan, LU Fang-yun, WANG Shao-long, YAN Peng, LUO Yong-feng, YUAN Wei, HU Jian
2011, 31(3): 306-310. doi: 10.11883/1001-1455(2011)03-0306-05
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Basedonthefactthatinanexperimentaldevicefilledwithexplosiveandfluoride,theexplosionofthecentralexplosivecoulddispersethefluorideoutofthedevice, thenthefluoridewouldintenselyreactwiththeliquidintheconfinedcontainerandreleaseplentifulenergy, threeexperiments withdifferentexplosiondepthswerecarriedoutinsmall-scaleconfinedcontainerstoevaluatethedamagepowerofthisdeviceaccordingtotheoverpressure- impulsecriterion.AndtheTNTequivalent massofthisdevicewascalculated.Theexperimentwiththeexplosiondepthof1.2mwasnumerically simulatedbyusingtheexperimentaldata.Themaximumdispersalvelocityofthetopcoverobtained bysimulationisclosetotheexperimentalresult.Itdisplaysthatthegivenevaluationmethodisfeasible.
Experimentonplasma-liquidinteraction inastepped-wallchamber
ZHANG Qi, YU Yong-gang, LU Xin, LIU Dong-yao
2011, 31(3): 311-316. doi: 10.11883/1001-1455(2011)03-0311-06
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Toexploretheinfluenceofthechamberboundaryshapeonthecombustioncontrolina bulk-loadedliquid-mediumelectrothermal-chemicalgun,theplasmajetpropagationintheliquidmediumwasexperimentallyinvestigatedbyusingahigh- speeddigitalcamera.Specialattentionwaspaidto theplasmajet-liquidmediuminteractionundertheconditionsofdifferentdischargevoltages,different nozzlediametersanddifferentdivergentboundaries.Thetime-sequencephotosoftheplasmajetpropagationintheliquidmedium wereobtained,fromthephotostheaxialdisplacementhistoriesofthe Taylorcavitywereachievedunderthedifferentconditions,andthecorrespondingpropagationvelocitiesoftheTaylorcavitywerecalculated. Sequentially,theinteractionmechanismbetweentheplasma jetandtheliquidmediumwasanalyzed.TheresultsindicatethatthoughtheaxialvelocityoftheTaylorcavityisfluctuant, asawholeitisdecrescent;andthatatthewallsteps,theradialturbulenceof theplasmajetisenhanced,whichcanstrengthentheentrainmenteffectofreflux.
Ignitioncharacteristicsofsemiconductorbridges withandwithoutLTNR
MA Peng, ZHANG Lin, ZHU Shun-guan, ZHANG Lei, CHEN Hou-he
2011, 31(3): 317-321. doi: 10.11883/1001-1455(2011)03-0317-05
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Abstract:Bytakingthepulsedischargeswithdifferentcapacitancesastheinputenergy,semiconductorbridges( SCB)withandwithoutleadtrinitroresorcinate(LTNR)wereexperimentallyinvestigated, respectively.Experimentalresultsshowthatthereexistdifferencesinignitionenergy,plasma secondpeakappearancetimeanditsdurationtimeaswellasitspeakvoltagebetweenthetwokindsof SCBs.TheintegralenergyofthebareSCBishigherthanthatoftheSCBwithLTNRatthesamecapacitanceanditchangeslinearlywithcapacitance, buttheintegralenergyoftheSCBwithLTNRis nearlychangeless.ThereasonliesinthefactthattheplasmaofthebareSCBisgeneratedintheair, butforthechargedSCBtheplasmageneratedisusedtoheatLTNRandthenthedecompositionheat ofLTNRcanmaintainthefollowingreaction.Furthermore,theplasmasecondpeakappearanceofthe bareSCBislater,thesecondpeakdurationtimeislonger,andthepeakvoltageofthesecondpeakis lowerthanthoseofthechargedSCBatthesamecapacitance.
Animprovedsideline/erodingalgorithm
ZHANG Feng-guo, HAN Bing, HE Chang-jiang
2011, 31(3): 322-325. doi: 10.11883/1001-1455(2011)03-0322-04
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Aslideline/erodingalgorithm,whichwasimplementedintothe2DLagrangianelasticityplasticityhydrodynamiccodeLTZ- 2D,wasimproved.Thecellerodingcriterionwaschangedfromthe accumulativeplasticstraintoanintegratedcriterionmadeoftheaccumulativeplasticstrain,thedimensionlessstiffnessfactorandtheangleoppositetheslideline. Andthepenetrationproblemswere numericallysimulatedbytheimprovedalgorithm.Calculatedresultsdisplaythattheimprovedalgorithmcanresolvetheinterfacebetweenthetwoimpactingbodiesandsmoothoutthecurvatureofth slideline.
Time-frequencyrepresentationanalysisinunderwaterexplosiveshockwave signalsbasedonanimprovedHHTmethod
CHENG Lei, HAN Yan, WANG Jian, DU Juan
2011, 31(3): 326-331. doi: 10.11883/1001-1455(2011)03-0326-06
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Abstract:
Basedonthecharactersofunderwaterexplosionshockwaves,animprovedHilbert-Huang transform (HHT)methodwasproposedbytakingtheadvantageofHHTinprocessingnon-stationarysignalsandcombiningwaveletdecompositionandcorrelationcoefficientfiltering. Intheimproved HHT method,firstsignalsaredividedintohigh-frequencysignalsandlow-frequencysignalsbywaveletdecomposition, andthenintrinsicmodefunction(IMF)componentsarefilteredbycorrelationcoefficients. Resultsshowthattheimproved HHT methodcanbeappliedtoeffectivelyanalyzethe time-frequencyinformationofunderwaterexplosionshockwavesignals.
ExplosiveconsolidationofW-Cualloyaslinermaterials anditsperformance
WANG Zhan-lei, LI Xiao-jie, ZHANG Cheng-jiao, YI Cai-hong, WANG Hai-tao, SUN Wei
2011, 31(3): 332-336. doi: 10.11883/1001-1455(2011)03-0332-05
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Abstract:
TheW-Cualloypowderswerepreparedbyhigh-energyball-milling.TheW-Cualloyaslinermaterialswasfabricatedbyexplosiveconsolidation. Theconsolidatedsamplehadatheoreticaldensityof99.6%. ThesamplewasdeterminedbyEPMA,andtheresultsshowedthatthecomposition anddistributionoftheelementswereuniform.ThesamplewasanalyzedbyXRDandtheWcrystallinesizesweremeasuredas26nm. ThesamplewasmachinedintoW-Cualloyliners,showinggood formingproperties.Quietarmor-piercingexperimentoftheW-Cualloylinerofshapedchargewithout aninsulatingboardindicatesthatthearmor-piercingcapabilityincreasesby31.8percentincomparisonwiththecopperliner.