2010 Vol. 30, No. 4
Display Method:
2010, 30(4): 337-341.
doi: 10.11883/1001-1455(2010)04-0337-05
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Abstract:
Basedonthemulticomponentthree-dimensionalEulerequation,thephenomenaofrotating detonationintheannularcombustorweresimulatednumerically,andthethree-dimensionalstructure oftherotatingdetonationwaveandtheeffectsofthelateralrarefactionwavesonthedetonationwave frontwerediscussed.Thenumericalresultsshowthattherotatingdetonationwavecanpropagate steadilyinthelayerofpremixedgas,andthedetonationwavefrontisdistortedduetothelateralrarefactionwaves. ComparedwiththeidealCJdetonation,theintensityandparametersofrotatingdetonationwavebothdeclinesomewhat.
Basedonthemulticomponentthree-dimensionalEulerequation,thephenomenaofrotating detonationintheannularcombustorweresimulatednumerically,andthethree-dimensionalstructure oftherotatingdetonationwaveandtheeffectsofthelateralrarefactionwavesonthedetonationwave frontwerediscussed.Thenumericalresultsshowthattherotatingdetonationwavecanpropagate steadilyinthelayerofpremixedgas,andthedetonationwavefrontisdistortedduetothelateralrarefactionwaves. ComparedwiththeidealCJdetonation,theintensityandparametersofrotatingdetonationwavebothdeclinesomewhat.
2010, 30(4): 342-348.
doi: 10.11883/1001-1455(2010)04-0342-07
Abstract:
Thevolume-acceleration modelwasintroducedtodeterminetheinitialconditionsforthe motionofanunderwaterexplosionbubble.AsubcodewritteninFortranlanguagewasdevelopedto definetheinitialandboundaryconditionsforthefluidfield.Bycombiningthefiniteelementanalysis softwareMSC.Dytranandtheself-developedsubcode,thedynamicbehaviorsofthebubbleweresimulatedincludingoscillation, collapse,jetandsoon.Thecomputationalvolume-timecurvesofthe bubbleinthispaperaremoreconsistentwiththeexperimentalresultsthanthosebytheboundaryintegralmethod. Thedynamiccharacteristicsofthebubble,whichconsistofvolume,maximalradius, period,jetvelocity,andsoon,havecloserelationswiththechargemassandwaterdepth.Theobtainedcurvesarehelpfulforthecorrelativetheoryresearchandengineeringcalculation.
Thevolume-acceleration modelwasintroducedtodeterminetheinitialconditionsforthe motionofanunderwaterexplosionbubble.AsubcodewritteninFortranlanguagewasdevelopedto definetheinitialandboundaryconditionsforthefluidfield.Bycombiningthefiniteelementanalysis softwareMSC.Dytranandtheself-developedsubcode,thedynamicbehaviorsofthebubbleweresimulatedincludingoscillation, collapse,jetandsoon.Thecomputationalvolume-timecurvesofthe bubbleinthispaperaremoreconsistentwiththeexperimentalresultsthanthosebytheboundaryintegralmethod. Thedynamiccharacteristicsofthebubble,whichconsistofvolume,maximalradius, period,jetvelocity,andsoon,havecloserelationswiththechargemassandwaterdepth.Theobtainedcurvesarehelpfulforthecorrelativetheoryresearchandengineeringcalculation.
2010, 30(4): 349-354.
doi: 10.11883/1001-1455(2010)04-0349-06
Abstract:
Numericalsimulationswerecarriedouttoinvestigatethecharacteristicsofstandingoblique detonationwave(ODW)fordifferentMach6.8,7.0and7.5inletflowsoverawedgeof30turning angle.NumericalresultsshowashockwaveatMach6.8and7.0appearsatthedownstreamofthe triplepointwhichisformedamongobliqueshockwave(OSW),ODWanddeflagrationwave,reflects fromthewedgewall,passesacrossthecontactsurfaceandinteractswithtransversewaveswhichoriginatingfromtheODWfront. Thisinteractionmakescellularstructureirregularandcomplex.At thesametime,anewfeatureshowsthetransversewavespropagatebothinone-waydirectionupstreamandintwo- waydirectiondownstreambehindtheODW.Thepropagationcharacteristicaffects thestabilityofobliquedetonationwave.
Numericalsimulationswerecarriedouttoinvestigatethecharacteristicsofstandingoblique detonationwave(ODW)fordifferentMach6.8,7.0and7.5inletflowsoverawedgeof30turning angle.NumericalresultsshowashockwaveatMach6.8and7.0appearsatthedownstreamofthe triplepointwhichisformedamongobliqueshockwave(OSW),ODWanddeflagrationwave,reflects fromthewedgewall,passesacrossthecontactsurfaceandinteractswithtransversewaveswhichoriginatingfromtheODWfront. Thisinteractionmakescellularstructureirregularandcomplex.At thesametime,anewfeatureshowsthetransversewavespropagatebothinone-waydirectionupstreamandintwo- waydirectiondownstreambehindtheODW.Thepropagationcharacteristicaffects thestabilityofobliquedetonationwave.
2010, 30(4): 355-360.
doi: 10.11883/1001-1455(2010)04-0355-06
Abstract:
TheJohnson-Cookconstitutiverelationsanddamagemodelwereintroducedintothereproducingkernelparticle( RKP)method,andanewinterfacecalculationmethodandacollocationmethodwereproposedtosolvetheproblemsofinterfaceandglidingparticles, realizetheboundaryconditionsandadjusttheparticlevelocityinthecomputationalprocess. TheimprovedRKP methodwas appliedtonumericallyanalyzetheobliquepenetrationprocessofasteelcylindricalpelletintoafixed steelplate.Inthecomputation,thepelletandtargetplateweredividedintokernelparticlesother thanelements.ComputationalresultsshowthattheimprovedRKP methodcanavoidthefiniteelementdeformationinthefiniteelementmethodandtheelementreconstructioninthedamageprocess andenhanceanalysisaccuracyandcomputationalspeed.AndtheimprovedRKPmethodcanbeused toconvenientlyanalyzethelargedeformationandhighstrainratephenomenainpenetrationprocess.
TheJohnson-Cookconstitutiverelationsanddamagemodelwereintroducedintothereproducingkernelparticle( RKP)method,andanewinterfacecalculationmethodandacollocationmethodwereproposedtosolvetheproblemsofinterfaceandglidingparticles, realizetheboundaryconditionsandadjusttheparticlevelocityinthecomputationalprocess. TheimprovedRKP methodwas appliedtonumericallyanalyzetheobliquepenetrationprocessofasteelcylindricalpelletintoafixed steelplate.Inthecomputation,thepelletandtargetplateweredividedintokernelparticlesother thanelements.ComputationalresultsshowthattheimprovedRKP methodcanavoidthefiniteelementdeformationinthefiniteelementmethodandtheelementreconstructioninthedamageprocess andenhanceanalysisaccuracyandcomputationalspeed.AndtheimprovedRKPmethodcanbeused toconvenientlyanalyzethelargedeformationandhighstrainratephenomenainpenetrationprocess.
2010, 30(4): 361-369.
doi: 10.11883/1001-1455(2010)04-0361-09
Abstract:
IntegratedwithrelativeSHPBtests,theadiabaticsheardeformationofspecimenisobservedbasedonaseriesofnumericalsimulationsofSHPBtestusing921Asteelpureshearhat- shaped specimens.Theinitiationandthepropagationofanadiabaticshearband(ASB)andtherelativedistributionoftemperaturefieldinthespecimenareanalyzed. ItisfoundthatASBisformedasthespread ofanunstablezonewithhightemperatureandhighstraininthetwoendsofshearzone.Thespread speedofanASBisrelatedtotheloadingrate,whilstthewidthofASBisnearlyindependentofthe loadingrate,andequalstoabout70m,i.e.,thewidthofthedesignedshearzone.AlltheASBsare deformedbandscorrespondingtovariousvaluesoftheloadingrate.
IntegratedwithrelativeSHPBtests,theadiabaticsheardeformationofspecimenisobservedbasedonaseriesofnumericalsimulationsofSHPBtestusing921Asteelpureshearhat- shaped specimens.Theinitiationandthepropagationofanadiabaticshearband(ASB)andtherelativedistributionoftemperaturefieldinthespecimenareanalyzed. ItisfoundthatASBisformedasthespread ofanunstablezonewithhightemperatureandhighstraininthetwoendsofshearzone.Thespread speedofanASBisrelatedtotheloadingrate,whilstthewidthofASBisnearlyindependentofthe loadingrate,andequalstoabout70m,i.e.,thewidthofthedesignedshearzone.AlltheASBsare deformedbandscorrespondingtovariousvaluesoftheloadingrate.
2010, 30(4): 370-376.
doi: 10.11883/1001-1455(2010)04-0370-07
Abstract:
ByamendingtheSHOCKcodeintheFortranchemicalkineticspackage,CHEMKIN Ⅲ,a computationalmodelwasbuiltfortheshockwave-inducedgasexplosioninashocktube.And,the detailedreactionmechanismsinvolving53speciesand325reactionswereadoptedinthemodelabove. Thebuiltcomputationalmodelwasusedtoanalyzetheevolvementsofthefollowingparameters: mixedgastemperature,shockwavevelocity,themolefractionsofreactants(CH4andO2),themole fractionsofactivecenters(O,H),andthemolefractionsofcatastrophicgases(CO,CO2,NOand NO2)intheprocessofgasexplosioninducedbyshockwave.Furthermore,theeffectsoftheinitial pressureandthemixedgascompositionbeforegasexplosiononthekineticcharacteristicsofgasexplosioninducedbyshockwavewerediscussed. TheresultsshowthatthemolefractionsofCO,CO2, NOandNO2areabout0.07,0.02,0.001and10-6,respectively,aftergasexplosion.WiththeincreaseoftheinitialpressureandthedecreaseoftheCH4fractioninthemixedgas, thedetonationtime ofgasexplosionshortens,thetemperaturedecreases,butthepressureincreasesaftergasexplosion. Meanwhile,themolefractionofCOdecreases,themolefractionofNOincreases.
ByamendingtheSHOCKcodeintheFortranchemicalkineticspackage,CHEMKIN Ⅲ,a computationalmodelwasbuiltfortheshockwave-inducedgasexplosioninashocktube.And,the detailedreactionmechanismsinvolving53speciesand325reactionswereadoptedinthemodelabove. Thebuiltcomputationalmodelwasusedtoanalyzetheevolvementsofthefollowingparameters: mixedgastemperature,shockwavevelocity,themolefractionsofreactants(CH4andO2),themole fractionsofactivecenters(O,H),andthemolefractionsofcatastrophicgases(CO,CO2,NOand NO2)intheprocessofgasexplosioninducedbyshockwave.Furthermore,theeffectsoftheinitial pressureandthemixedgascompositionbeforegasexplosiononthekineticcharacteristicsofgasexplosioninducedbyshockwavewerediscussed. TheresultsshowthatthemolefractionsofCO,CO2, NOandNO2areabout0.07,0.02,0.001and10-6,respectively,aftergasexplosion.WiththeincreaseoftheinitialpressureandthedecreaseoftheCH4fractioninthemixedgas, thedetonationtime ofgasexplosionshortens,thetemperaturedecreases,butthepressureincreasesaftergasexplosion. Meanwhile,themolefractionofCOdecreases,themolefractionofNOincreases.
2010, 30(4): 377-382.
doi: 10.11883/1001-1455(2010)04-0377-06
Abstract:
Complexmeasuredvelocitysignalsofblastingvibrationaretransformedintothesuperpositionofseveralsimpleharmonicwavesbythewaveletpac etdecompositionandreconstructiontechniques. Inthisway,theproblemofstructuraldynamicresponseundertheactionofblastingvelocity loadbecomestheproblemofthatunderaseriesofsimpleharmonicloads.Byintroducinganewconceptofvelocityfactorintothecomputationalmodelofblastingvibrationeffect, thecontributionof structuraltransientresponseisconsideredintostructuraldynamicresponse.Atthemeantime,normalizedenergyproportionisaddedtothecomputationalmodel, andonlydominantfrequenciesofrelativelylargeenergyproportionscanbeincludedwhenconsideringtheinfluenceofblastingloadfrequencies Then,onthebasisofthemodelabove,anewsafetycriterionofblastingvibrationeffectis putforward,whichcanreflecttherelationbetweenthestructuralvelocityresponsemagnitudeunder blastingloadstimulationandthefollowingparameters:structuralcharacteristics,amplitude,frequenciesincludingseveraldominantfrequencies, durationandenergyproportionofblastingload.In theend,bycombiningwithanactualengineeringcase,velocityresponseamplitudesarecalculatedby thecomputationalmodelputforwardinthispaperandthetemporalanalysismethod,respectively. Andthecomputationalresultsshowthatthiscomputationalmodelisfeasible.
Complexmeasuredvelocitysignalsofblastingvibrationaretransformedintothesuperpositionofseveralsimpleharmonicwavesbythewaveletpac etdecompositionandreconstructiontechniques. Inthisway,theproblemofstructuraldynamicresponseundertheactionofblastingvelocity loadbecomestheproblemofthatunderaseriesofsimpleharmonicloads.Byintroducinganewconceptofvelocityfactorintothecomputationalmodelofblastingvibrationeffect, thecontributionof structuraltransientresponseisconsideredintostructuraldynamicresponse.Atthemeantime,normalizedenergyproportionisaddedtothecomputationalmodel, andonlydominantfrequenciesofrelativelylargeenergyproportionscanbeincludedwhenconsideringtheinfluenceofblastingloadfrequencies Then,onthebasisofthemodelabove,anewsafetycriterionofblastingvibrationeffectis putforward,whichcanreflecttherelationbetweenthestructuralvelocityresponsemagnitudeunder blastingloadstimulationandthefollowingparameters:structuralcharacteristics,amplitude,frequenciesincludingseveraldominantfrequencies, durationandenergyproportionofblastingload.In theend,bycombiningwithanactualengineeringcase,velocityresponseamplitudesarecalculatedby thecomputationalmodelputforwardinthispaperandthetemporalanalysismethod,respectively. Andthecomputationalresultsshowthatthiscomputationalmodelisfeasible.
2010, 30(4): 383-389.
doi: 10.11883/1001-1455(2010)04-0383-07
Abstract:
Toinvestigatethewavepropagationfeaturesinanisotropicmaterialsunderplane-strainconditions, anelastic-plasticconstitutivemodelwasconstructedbycombiningtheHookeslawofanisotropicmaterial, theTsai-Hillyieldcriterion,theclassicfundamentalprinciplesofplasticmechanics andthemodifiedGrneisenequationofstateconsideringthenonlinearcompressibilityofvolumeat highpressures.Andbasedontwo-dimensionalmaterialdeformation,therotationofmaterialprincipal axesandthemodificationofobjectivestressratewerediscussed.Thenaself-developed,explicit,dynamic, finiteelementcodewasappliedtosimulatetheplane-stresswavepropagationincertainanisotropicfiber- enforcedcompositesduringcollision.Theresultsshowthatstresswavespropagatingin theabovematerialdisplaytwo-dimensional,anisotropicandelastic-plasticfeaturesunderplane-strain conditions.
Toinvestigatethewavepropagationfeaturesinanisotropicmaterialsunderplane-strainconditions, anelastic-plasticconstitutivemodelwasconstructedbycombiningtheHookeslawofanisotropicmaterial, theTsai-Hillyieldcriterion,theclassicfundamentalprinciplesofplasticmechanics andthemodifiedGrneisenequationofstateconsideringthenonlinearcompressibilityofvolumeat highpressures.Andbasedontwo-dimensionalmaterialdeformation,therotationofmaterialprincipal axesandthemodificationofobjectivestressratewerediscussed.Thenaself-developed,explicit,dynamic, finiteelementcodewasappliedtosimulatetheplane-stresswavepropagationincertainanisotropicfiber- enforcedcompositesduringcollision.Theresultsshowthatstresswavespropagatingin theabovematerialdisplaytwo-dimensional,anisotropicandelastic-plasticfeaturesunderplane-strain conditions.
2010, 30(4): 390-394.
doi: 10.11883/1001-1455(2010)04-0390-05
Abstract:
Theexplosivepentaerythritoltetranitrate(PETN)wasproportionallymixedwithnickel/ cobaltnitrate,carbamide,andabsoluteethylalcoholtoobtainwatersolubleexplosives.Theobtained watersolubleexplosiveswereignitedbythedetonatorsundernitrogenprotectioninexplosionvessels tosynthesizecarbon-encapsulatednickel/cobaltparticles.Theshape,compositionandstructureofthe detonationproductswerecharacterizedbyTEM,X-raydiffraction(XRD)andRamanspectroscopy. Andtheformationmechanismofthecarbon-encapsulatednanocrystalswastentativelydiscussed.The resultsshowthatthedetonationsootconsistsofmetalnanocrystalsascoresandamorphouscarbon, graphiteandalittlefullereneascarbon-coatinglayers.
Theexplosivepentaerythritoltetranitrate(PETN)wasproportionallymixedwithnickel/ cobaltnitrate,carbamide,andabsoluteethylalcoholtoobtainwatersolubleexplosives.Theobtained watersolubleexplosiveswereignitedbythedetonatorsundernitrogenprotectioninexplosionvessels tosynthesizecarbon-encapsulatednickel/cobaltparticles.Theshape,compositionandstructureofthe detonationproductswerecharacterizedbyTEM,X-raydiffraction(XRD)andRamanspectroscopy. Andtheformationmechanismofthecarbon-encapsulatednanocrystalswastentativelydiscussed.The resultsshowthatthedetonationsootconsistsofmetalnanocrystalsascoresandamorphouscarbon, graphiteandalittlefullereneascarbon-coatinglayers.
2010, 30(4): 395-400.
doi: 10.11883/1001-1455(2010)04-0395-06
Abstract:
Aimedatfragmentpenetrationintofluidcabinbulkhead,atheoreticalanalysismodelwas establishedtoexplorethepenetrationprocessofwater-backedtargets.Basedontheenergyanalysis,a formulafortheresidualvelocityofthefragmentafterthewater-backedtargetpenetrationwasderived bycombiningthemotionequationandtheDeMarremodel.Thederivedformulawasappliedtocalculatetheresidualvelocitiesofthefragmentswiththeinitialvelocitiesof1.0~ 1.6km/s.Andthepenetrationprocessofthefragmentsintothewater- backedtargetwasmodeledbyusingthenon-lineardynamicsanalysissoftware, AUTODYN.Theresidualvelocitiesbythederivedformulaareinagreementwiththosebythesoftware, AUTODYN.Theresidualvelocitiesobtainedabovewerecompared withthosebytheexistentformulaforthefragmentswiththesameinitialvelocitiesaftertheairbackedtargetpenetration. Comparisonshowsthatthefluidbehindthebulkheadcanpreventfragment penetrationtoacertainextent,andthattheresidualvelocityinthecaseoftheair-backedtargetpenetrationismarkedlylowerthanthatinthecaseofthewater- backedtargetpenetration.Thehigherthe initialvelocityofthefragment,thegreaterthefluidresistance,theclearerthevelocityattenuation.
Aimedatfragmentpenetrationintofluidcabinbulkhead,atheoreticalanalysismodelwas establishedtoexplorethepenetrationprocessofwater-backedtargets.Basedontheenergyanalysis,a formulafortheresidualvelocityofthefragmentafterthewater-backedtargetpenetrationwasderived bycombiningthemotionequationandtheDeMarremodel.Thederivedformulawasappliedtocalculatetheresidualvelocitiesofthefragmentswiththeinitialvelocitiesof1.0~ 1.6km/s.Andthepenetrationprocessofthefragmentsintothewater- backedtargetwasmodeledbyusingthenon-lineardynamicsanalysissoftware, AUTODYN.Theresidualvelocitiesbythederivedformulaareinagreementwiththosebythesoftware, AUTODYN.Theresidualvelocitiesobtainedabovewerecompared withthosebytheexistentformulaforthefragmentswiththesameinitialvelocitiesaftertheairbackedtargetpenetration. Comparisonshowsthatthefluidbehindthebulkheadcanpreventfragment penetrationtoacertainextent,andthattheresidualvelocityinthecaseoftheair-backedtargetpenetrationismarkedlylowerthanthatinthecaseofthewater- backedtargetpenetration.Thehigherthe initialvelocityofthefragment,thegreaterthefluidresistance,theclearerthevelocityattenuation.
2010, 30(4): 401-406.
doi: 10.11883/1001-1455(2010)04-0401-06
Abstract:
ShandongProvincialKeyLaboratoryofCivilEngineeringDisasterPreventionand Mitigation, ShandongUniversityofScienceandTechnology,Qingdao266510,Shandong,China
ShandongProvincialKeyLaboratoryofCivilEngineeringDisasterPreventionand Mitigation, ShandongUniversityofScienceandTechnology,Qingdao266510,Shandong,China
2010, 30(4): 407-412.
doi: 10.11883/1001-1455(2010)04-0407-06
Abstract:
Themovablecellularautomata(MCA)methodwasimprovedandappliedtosimulatethe penetrationprocessoftungstenlongrodprojectilesinto27SiMnMotargetplates.Atanimpactvelocityof1000m/ s,thesimulatedresultsshowthatdifferentaspectratioscorrespondtodifferentmaximalpenetrationdepthsandthemaximalpenetrationdepthincr aseswiththeincreaseoftheaspectratio, buttheaspectratiosover25affectweaklypenetrationdepthunderthegivenexperimentalconditions. Thecomputedtemperaturefieldsfortheprojectilesandtargetsareinagreementwiththeexperimentalresults. Themovablecellularautomata(MCA)methodcanbeusedtoeffectivelyanalyze thedamageprocessoftheprojectile-targetinteraction.
Themovablecellularautomata(MCA)methodwasimprovedandappliedtosimulatethe penetrationprocessoftungstenlongrodprojectilesinto27SiMnMotargetplates.Atanimpactvelocityof1000m/ s,thesimulatedresultsshowthatdifferentaspectratioscorrespondtodifferentmaximalpenetrationdepthsandthemaximalpenetrationdepthincr aseswiththeincreaseoftheaspectratio, buttheaspectratiosover25affectweaklypenetrationdepthunderthegivenexperimentalconditions. Thecomputedtemperaturefieldsfortheprojectilesandtargetsareinagreementwiththeexperimentalresults. Themovablecellularautomata(MCA)methodcanbeusedtoeffectivelyanalyze thedamageprocessoftheprojectile-targetinteraction.
2010, 30(4): 413-418.
doi: 10.11883/1001-1455(2010)04-0413-06
Abstract:
Theexistentshot-lineconceptwasextendedbasedonthevisualC~(+ +)and Matlab codes.Acomputationalmethodwasdevelopedbysettingupthecomputationalmodelofthedamage fieldparameters,whichconsistingoftheinitialvelocity,dispersiondirection,velocityattenuation, andsoon,forthepreformedorhalf-preformedfragmentwarheadattackingthetarget,andthetransformationofthefragmentpowerparametersinthespacecoordinate. Andanewcomputationalmethodwasachievedtopredicttheshot- linefielddistributionofthefragmentwarheadbyusingthecombinedprogram withvisualC~(++)andMATLAB.Acomputationalexamplewasgivenbyapplyingtheachievedcomputationalmethodtodeterminetheshot- linefielddistributionofthefragment warheadunderdifferentexplosionconditionsattackingtheplanetarget.Thecomputationalresultsdescribeddistinctlythedamagefielddistributionofthewarheadfragmentstotheplaneandreflectedvisuallythetra ectoriesandenergyattenuationsofallthewarheadfragments.Theachievedcomputationalmethodwasvalidatedbythecomparisonbetweenthecomputationaldatawiththeknownexperimentalresults. Thisresearchcanprovideanewreferenceforthewarheaddesignandterminaldamageeffectanalysis.
Theexistentshot-lineconceptwasextendedbasedonthevisualC~(+ +)and Matlab codes.Acomputationalmethodwasdevelopedbysettingupthecomputationalmodelofthedamage fieldparameters,whichconsistingoftheinitialvelocity,dispersiondirection,velocityattenuation, andsoon,forthepreformedorhalf-preformedfragmentwarheadattackingthetarget,andthetransformationofthefragmentpowerparametersinthespacecoordinate. Andanewcomputationalmethodwasachievedtopredicttheshot- linefielddistributionofthefragmentwarheadbyusingthecombinedprogram withvisualC~(++)andMATLAB.Acomputationalexamplewasgivenbyapplyingtheachievedcomputationalmethodtodeterminetheshot- linefielddistributionofthefragment warheadunderdifferentexplosionconditionsattackingtheplanetarget.Thecomputationalresultsdescribeddistinctlythedamagefielddistributionofthewarheadfragmentstotheplaneandreflectedvisuallythetra ectoriesandenergyattenuationsofallthewarheadfragments.Theachievedcomputationalmethodwasvalidatedbythecomparisonbetweenthecomputationaldatawiththeknownexperimentalresults. Thisresearchcanprovideanewreferenceforthewarheaddesignandterminaldamageeffectanalysis.
2010, 30(4): 419-423.
doi: 10.11883/1001-1455(2010)04-0419-05
Abstract:
Aneffectivenumericalsolverwasdevelopedforcompressiblemulti-componentfluidflows bycombiningalevelsetmethodfortheinterfacetracking,aRunge-kuttadiscontinuousfiniteelement methodforthediscretizationoftheEulerequationsandasimplefixmethodforpreventingspurious oscillationsneartheinterface.Incalculation,thespecific-heatratiooftheflowandanewsignfunctionweredefinedbyusingasmoothHeavisidefunction. Resultsshowthatthedevelopedmethodis feasibleforsolvingcompressiblemulti-componentfluidflows.
Aneffectivenumericalsolverwasdevelopedforcompressiblemulti-componentfluidflows bycombiningalevelsetmethodfortheinterfacetracking,aRunge-kuttadiscontinuousfiniteelement methodforthediscretizationoftheEulerequationsandasimplefixmethodforpreventingspurious oscillationsneartheinterface.Incalculation,thespecific-heatratiooftheflowandanewsignfunctionweredefinedbyusingasmoothHeavisidefunction. Resultsshowthatthedevelopedmethodis feasibleforsolvingcompressiblemulti-componentfluidflows.
2010, 30(4): 424-428.
doi: 10.11883/1001-1455(2010)04-0424-05
Abstract:
AluminumfibrewasaddedintoTNTandRDXexplosives,respectively,tosynthesizecompositeexplosiveswiththealuminum- fibremassfractionof0.2.Airblastexperimentswereconducted inasteelexplosion-containmentvesseltoinvestigatetheeffectsofaluminumfibreontheexplosiveenergyoutput. Resultsdisplaythattheoverpressureandexplosionheatofthealuminum-fibre-reinforcedcompositeTNTexplosivearriveat1.19and1.29timesashighasthoseofthepureTNTexplosive, respectively.Theoverpressureandexplosionheatofthealuminum-fibre-reinforcedcompositeRDXexplosivearriveat1.20and1.31timesashighasthoseofthepureRDXexplosive, respectively. Andtheexplosionheatofthealuminum-fibre-reinforcedcompositeRDXexplosiveis1.64 timesasmuchasthatofthepureTNTexplosive.Mechanicalstrengthtestswereperformedbya WDW4100almightytestsystemtoanalyzetheeffectsofaluminumfibreonthemechanicalstrengthof TNTexplosives.TestresultsshowthatthedamagestressofthecompositeTNTexplosiveisupto6. 87MPaandthecorrespondingstrainis0.043.Andaluminumfibrecanimprovethe mechanical strengthofexplosives.Thisresearchcanprovidereferenceforthedesignofhighexplosives.
AluminumfibrewasaddedintoTNTandRDXexplosives,respectively,tosynthesizecompositeexplosiveswiththealuminum- fibremassfractionof0.2.Airblastexperimentswereconducted inasteelexplosion-containmentvesseltoinvestigatetheeffectsofaluminumfibreontheexplosiveenergyoutput. Resultsdisplaythattheoverpressureandexplosionheatofthealuminum-fibre-reinforcedcompositeTNTexplosivearriveat1.19and1.29timesashighasthoseofthepureTNTexplosive, respectively.Theoverpressureandexplosionheatofthealuminum-fibre-reinforcedcompositeRDXexplosivearriveat1.20and1.31timesashighasthoseofthepureRDXexplosive, respectively. Andtheexplosionheatofthealuminum-fibre-reinforcedcompositeRDXexplosiveis1.64 timesasmuchasthatofthepureTNTexplosive.Mechanicalstrengthtestswereperformedbya WDW4100almightytestsystemtoanalyzetheeffectsofaluminumfibreonthemechanicalstrengthof TNTexplosives.TestresultsshowthatthedamagestressofthecompositeTNTexplosiveisupto6. 87MPaandthecorrespondingstrainis0.043.Andaluminumfibrecanimprovethe mechanical strengthofexplosives.Thisresearchcanprovidereferenceforthedesignofhighexplosives.
2010, 30(4): 429-432.
doi: 10.11883/1001-1455(2010)04-0429-04
Abstract:
Therelativepositionsofincidentwave,transmission waveandreflection wavecanbe changedbytheself-developedprogram.Whentherelativepositionofthewavesisadjusted,theselfdevelopedprogramgivestwoimages. Oneimagedisplaysincident,transmission,reflectionwavesand thedifferencebetweentransmissionandincidentwaves.Theotherimagelaysoutthethreestrainstresscurvesofthespecimen. Thethreecurvesareplottedseparatelythroughincidentandtransmissionwaves, incidentandreflectionwaves,andthethreewavesfromthefirstimage.Accordingtothe basicassumptionsoftheSHPBexperiment,thethreecurvesshouldbeconsistentintheplasticregion, andthedifferenceoftransmissionandincidentwavesshouldbeequaltothereflectivewave. Thetwoequivalentcharacteristicscanbeusedascriteriaoftreatingtheexperimentaldatacorrectlyor not.Thisexperimentaldatatreatmentmethodiscalledthethree-wavecheckingmethod.
Therelativepositionsofincidentwave,transmission waveandreflection wavecanbe changedbytheself-developedprogram.Whentherelativepositionofthewavesisadjusted,theselfdevelopedprogramgivestwoimages. Oneimagedisplaysincident,transmission,reflectionwavesand thedifferencebetweentransmissionandincidentwaves.Theotherimagelaysoutthethreestrainstresscurvesofthespecimen. Thethreecurvesareplottedseparatelythroughincidentandtransmissionwaves, incidentandreflectionwaves,andthethreewavesfromthefirstimage.Accordingtothe basicassumptionsoftheSHPBexperiment,thethreecurvesshouldbeconsistentintheplasticregion, andthedifferenceoftransmissionandincidentwavesshouldbeequaltothereflectivewave. Thetwoequivalentcharacteristicscanbeusedascriteriaoftreatingtheexperimentaldatacorrectlyor not.Thisexperimentaldatatreatmentmethodiscalledthethree-wavecheckingmethod.
2010, 30(4): 433-438.
doi: 10.11883/1001-1455(2010)04-0433-06
Abstract:
Toexplorethedynamicmechanicalpropertiesofhardenedsteel(45HRC),quasi-staticand dynamiccompressionexperimentswereperformedinthetemperaturerangefrom20℃to800℃and thestrainraterangefrom10-3s-1to104s-1 byusinganelectronicuniversaltestingmachineanda splitHopkinsonpressurebarsystem,respectively.Andthestress-straincurveswereexperimentally obtained.Theresultsindicatetheflowstressofhardened45steelisnotsensitivetostrainrate,but sensitivetotemperature.Theflowstressincreaseswiththeincreaseofstrainrateanddecreaseswith theincreaseoftemperature.Theconstitutiverelationshipofhardenedsteel(45HRC)underhightemperatureandhighstrainratewasfittedbytheimprovedJohnson- Cookconstitutiverelationshipin whichtheGaussianfunctionwasusedtodescribethetemperatureeffect.Thefittedcurveisingoodagreementwiththeexperimentaldata.
Toexplorethedynamicmechanicalpropertiesofhardenedsteel(45HRC),quasi-staticand dynamiccompressionexperimentswereperformedinthetemperaturerangefrom20℃to800℃and thestrainraterangefrom10-3s-1to104s-1 byusinganelectronicuniversaltestingmachineanda splitHopkinsonpressurebarsystem,respectively.Andthestress-straincurveswereexperimentally obtained.Theresultsindicatetheflowstressofhardened45steelisnotsensitivetostrainrate,but sensitivetotemperature.Theflowstressincreaseswiththeincreaseofstrainrateanddecreaseswith theincreaseoftemperature.Theconstitutiverelationshipofhardenedsteel(45HRC)underhightemperatureandhighstrainratewasfittedbytheimprovedJohnson- Cookconstitutiverelationshipin whichtheGaussianfunctionwasusedtodescribethetemperatureeffect.Thefittedcurveisingoodagreementwiththeexperimentaldata.
2010, 30(4): 439-444.
doi: 10.11883/1001-1455(2010)04-0439-06
Abstract:
ThecompressivebehaviorsofapressedPTFE/AlenergeticcompositematerialwereexperimentallyinvestigatedbysplitHopkinsonpressurebarsandquasi- staticbehaviorsbyauniversaltestingmachineatroomtemperature. Stress-straincurvesofthematerialwereobtainedinthestrainrate rangefrom10-3s-1to103 s-1.Accordingtotheanalysisonthecompressivebehavioratdifferent strainrates,theconstitutiverelationconsideringstrain-hardeningeffectandstrainrateeffectweredevelopedbasedontheJohnson- Cookplasticmodel.ThepenetrationofapressedPTFE/Alcomposite projectileintoasteeltargetwasnumericallysimulatedbyusingthedevelopedconstitutiverelation. Thesimulatedresultsareclosetotheexperimentalresults,whichvalidatesthereliabilityandrationalityofthedevelopedconstitutiverelation, andcanbeusedtoinstructtheapplicationofthePTFE/Al material.
ThecompressivebehaviorsofapressedPTFE/AlenergeticcompositematerialwereexperimentallyinvestigatedbysplitHopkinsonpressurebarsandquasi- staticbehaviorsbyauniversaltestingmachineatroomtemperature. Stress-straincurvesofthematerialwereobtainedinthestrainrate rangefrom10-3s-1to103 s-1.Accordingtotheanalysisonthecompressivebehavioratdifferent strainrates,theconstitutiverelationconsideringstrain-hardeningeffectandstrainrateeffectweredevelopedbasedontheJohnson- Cookplasticmodel.ThepenetrationofapressedPTFE/Alcomposite projectileintoasteeltargetwasnumericallysimulatedbyusingthedevelopedconstitutiverelation. Thesimulatedresultsareclosetotheexperimentalresults,whichvalidatesthereliabilityandrationalityofthedevelopedconstitutiverelation, andcanbeusedtoinstructtheapplicationofthePTFE/Al material.
2010, 30(4): 445-448.
doi: 10.11883/1001-1455(2010)04-0445-04
Abstract:
Theexperimentalsamplewiththedimensionsof25mm50mmwasformedwitha4-mmthickness2205duplexstainlesssteel( DSS)plateastheflyerbaseanda20-mm-thichness16MnRsteel plateasthebaseplatebyexplosivecombination.Theflyerplateandbaseplateweretreatedwithdifferentmethods, respectively.ThebondinginterfacemorphologywasobservedwithaNikonEpiphot 200inverted microscopeanda HitachiS-3000Nscanningelectron microscope (SEM).Thewhole bondinginterfaceismadeofstraightandvorticalbondzonesandcanbedividedintomeltandplastic deformationzones.AndEnergydispersivespectroscopyanalysisdisplaysthatthebondinginterface takesonasatisfactorymetallurgicalbond.TheexperimentalsampleswereannealedinanelectricresistancefurnaceSX- 4-10andthemicrohardnesswasmeasuredbyanHV-1000cleraometer.Afterthe samplewasheat-treatedat850℃for8handcooleduntil400℃,andcooledinair,inthe2205DSS platetherewas-phaseprecipitatedintheaustenite-ferriteinterspaceorinferrite.Andafterthesamplewasheat- treatedat700℃for8handcooleduntil400℃,andcooledinair,therewasnot-phase observedinthebondinginterface.Analysisofheattreatmentinfluencesonthemicrohardnessindicatesthatthemicrohardnessofthebaseandflyerplatesdecreaseswiththeincreas ngoftemperature andtimeofheattreatment.
Theexperimentalsamplewiththedimensionsof25mm50mmwasformedwitha4-mmthickness2205duplexstainlesssteel( DSS)plateastheflyerbaseanda20-mm-thichness16MnRsteel plateasthebaseplatebyexplosivecombination.Theflyerplateandbaseplateweretreatedwithdifferentmethods, respectively.ThebondinginterfacemorphologywasobservedwithaNikonEpiphot 200inverted microscopeanda HitachiS-3000Nscanningelectron microscope (SEM).Thewhole bondinginterfaceismadeofstraightandvorticalbondzonesandcanbedividedintomeltandplastic deformationzones.AndEnergydispersivespectroscopyanalysisdisplaysthatthebondinginterface takesonasatisfactorymetallurgicalbond.TheexperimentalsampleswereannealedinanelectricresistancefurnaceSX- 4-10andthemicrohardnesswasmeasuredbyanHV-1000cleraometer.Afterthe samplewasheat-treatedat850℃for8handcooleduntil400℃,andcooledinair,inthe2205DSS platetherewas-phaseprecipitatedintheaustenite-ferriteinterspaceorinferrite.Andafterthesamplewasheat- treatedat700℃for8handcooleduntil400℃,andcooledinair,therewasnot-phase observedinthebondinginterface.Analysisofheattreatmentinfluencesonthemicrohardnessindicatesthatthemicrohardnessofthebaseandflyerplatesdecreaseswiththeincreas ngoftemperature andtimeofheattreatment.
