2010 Vol. 30, No. 1
Display Method:
2010, 30(1): 1-6.
doi: 10.11883/1001-1455(2010)01-0001-06
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Abstract:
Aseriesofpenetrationtestsonconcretetargetsbysteelprojectilesatnormalincidencewere carriedoutbyusinghigh-velocitypenetrationequipments.Thepenetrationability,stabilityanddeformation/ fractureoftheprojectilesunderhigh-velocityimpactwereinvestigated.Itisshownthat transitionofsteelprojectilesfromrigidtodeformablestate,curvedtrajectory,projectileserosion andbending/failurearetypicalphenomenaobservedinhigh-speedpenetrationofconcretetargets.
Aseriesofpenetrationtestsonconcretetargetsbysteelprojectilesatnormalincidencewere carriedoutbyusinghigh-velocitypenetrationequipments.Thepenetrationability,stabilityanddeformation/ fractureoftheprojectilesunderhigh-velocityimpactwereinvestigated.Itisshownthat transitionofsteelprojectilesfromrigidtodeformablestate,curvedtrajectory,projectileserosion andbending/failurearetypicalphenomenaobservedinhigh-speedpenetrationofconcretetargets.
2010, 30(1): 7-11.
doi: 10.11883/1001-1455(2010)01-0007-05
Abstract:
Theequivalentstressesofhemisphericalshock-wavestrapstructurewerecalculatedbythe finiteelementprogramLS-DYNAfordifferentconstraintformsandcomparedwiththeexperimental results.Theresultsshowthatthestressconcentrationhappensontheshellneartheentranceandexhaustportandthelocalstressesarefarhigherthanthose fotherparts.Inadditiontothesiteof stressconcentration,themaximumstressisatthethree-fourthoftheheightforthescalespherical shellmodel.Theoverallstressleveldecreasessignificantlyforthesphericalshellwiththefreebottom. Usingthefreebasetoplacethesphericalshellcanfurtherenhanceitscapacityagainstspherical implosion.Contrastingwiththeexperiments,themaximumstresslocationisinlinewiththenumericalresultsafterreinforcingpartsofstressconcentration. Byusingthefreebasetoplacethespherical shellonthegroundinthedesign,itcannotonlyimprovetheanti-explosioncapacityofspherical shells,butalsosavethefoundationtreatment,substantiallyreducesthecostofhemisphericalshock wavestrapstructures.
Theequivalentstressesofhemisphericalshock-wavestrapstructurewerecalculatedbythe finiteelementprogramLS-DYNAfordifferentconstraintformsandcomparedwiththeexperimental results.Theresultsshowthatthestressconcentrationhappensontheshellneartheentranceandexhaustportandthelocalstressesarefarhigherthanthose fotherparts.Inadditiontothesiteof stressconcentration,themaximumstressisatthethree-fourthoftheheightforthescalespherical shellmodel.Theoverallstressleveldecreasessignificantlyforthesphericalshellwiththefreebottom. Usingthefreebasetoplacethesphericalshellcanfurtherenhanceitscapacityagainstspherical implosion.Contrastingwiththeexperiments,themaximumstresslocationisinlinewiththenumericalresultsafterreinforcingpartsofstressconcentration. Byusingthefreebasetoplacethespherical shellonthegroundinthedesign,itcannotonlyimprovetheanti-explosioncapacityofspherical shells,butalsosavethefoundationtreatment,substantiallyreducesthecostofhemisphericalshock wavestrapstructures.
2010, 30(1): 12-16.
doi: 10.11883/1001-1455(2010)01-0012-05
Abstract:
Theinitialstageofdetonationproductsdrivingwaterwastestedbyashadowphotography techniquewithahighspeedrotatingframecamera.Thephotographsoftheinterfacebetweendetonationproductsandwaterwereacquiredclearly. TestwassimulatedbyusingLS-DYNA.Theresults shownumericalsimulationaboutpositionandvelocityofinterface,shockwavetrajectory,isaccordantwiththetest. Parametersacquiredcanbeusedintheimprovedtest.Accordingtothetheoretical analysis,themaximuminstantaneoustemperatureofwaterdrivenbydetonationproductisabout342 K,whichislowerthanthephasechangetemperatureattheexperimentalpressure.
Theinitialstageofdetonationproductsdrivingwaterwastestedbyashadowphotography techniquewithahighspeedrotatingframecamera.Thephotographsoftheinterfacebetweendetonationproductsandwaterwereacquiredclearly. TestwassimulatedbyusingLS-DYNA.Theresults shownumericalsimulationaboutpositionandvelocityofinterface,shockwavetrajectory,isaccordantwiththetest. Parametersacquiredcanbeusedintheimprovedtest.Accordingtothetheoretical analysis,themaximuminstantaneoustemperatureofwaterdrivenbydetonationproductisabout342 K,whichislowerthanthephasechangetemperatureattheexperimentalpressure.
2010, 30(1): 17-20.
doi: 10.11883/1001-1455(2010)01-0017-04
Abstract:
WiththeL-J(Lennard-Jones12-6)potentialfunction,theshockHugoniotsofwaterwere calculatedbyusingVLWequationofstate.Thecalculationresultsagreewellwiththeexperimental datawhenthepotentialparameter/Kis120andb0is30.42.VLW EOScancharacterizetheshock HugoniotofwatermoreaccuratelythanBKW EOS.
WiththeL-J(Lennard-Jones12-6)potentialfunction,theshockHugoniotsofwaterwere calculatedbyusingVLWequationofstate.Thecalculationresultsagreewellwiththeexperimental datawhenthepotentialparameter/Kis120andb0is30.42.VLW EOScancharacterizetheshock HugoniotofwatermoreaccuratelythanBKW EOS.
2010, 30(1): 21-26.
doi: 10.11883/1001-1455(2010)01-0021-06
Abstract:
Vibrationattenuationandtopographiceffectweremonitoredneartheexplosionplaceof50t explosive.Basedontherecordedvibrationsignals,theattenuationsofverticalvelocityandaccelerationwereanalyzedwiththeSadauskasformula. Therapidattenuationofvibrationwasrelatedwith thelayeredmoderate-hardnessrocksandthelocalterrainandgully.Thetime-frequencydistribution ofthevibrationwasobtainedbythediscretewavelettransform (db8wavelet).Thefrequencyofvibrationenergyconcentrationwasreducedandthedurationofthevibrationwasprolongedwiththeincreaseofthedistancefromt eexplosioncenter.AccordingtotheChineseSeismicIntensityScale,the vibrationintensityclosetotheexplosioncenterisuptoⅦ,however,theblastingvibrationintensity decayfasterthantheattenuationofearthquakeintensity.Thetopographiceffectwasdiscussedby comparingthevibrationrecordsatdifferentlocationsofa14-m-highhill.Duetothefocusingvibrationenergyofthehill, thepeakaccelerationonthetopofthehillis2.4timeslargerthanthatatthe footofthehill,andthespecialfrequencybandswiththeenlargedamplitudeisrelatedwiththesize andtheheightofthehill.Thefigureofparticlemotionsindicatesthatthelateralswingandrotational motiongraduallyincreasefromthefoottothetopofthehill.
Vibrationattenuationandtopographiceffectweremonitoredneartheexplosionplaceof50t explosive.Basedontherecordedvibrationsignals,theattenuationsofverticalvelocityandaccelerationwereanalyzedwiththeSadauskasformula. Therapidattenuationofvibrationwasrelatedwith thelayeredmoderate-hardnessrocksandthelocalterrainandgully.Thetime-frequencydistribution ofthevibrationwasobtainedbythediscretewavelettransform (db8wavelet).Thefrequencyofvibrationenergyconcentrationwasreducedandthedurationofthevibrationwasprolongedwiththeincreaseofthedistancefromt eexplosioncenter.AccordingtotheChineseSeismicIntensityScale,the vibrationintensityclosetotheexplosioncenterisuptoⅦ,however,theblastingvibrationintensity decayfasterthantheattenuationofearthquakeintensity.Thetopographiceffectwasdiscussedby comparingthevibrationrecordsatdifferentlocationsofa14-m-highhill.Duetothefocusingvibrationenergyofthehill, thepeakaccelerationonthetopofthehillis2.4timeslargerthanthatatthe footofthehill,andthespecialfrequencybandswiththeenlargedamplitudeisrelatedwiththesize andtheheightofthehill.Thefigureofparticlemotionsindicatesthatthelateralswingandrotational motiongraduallyincreasefromthefoottothetopofthehill.
2010, 30(1): 27-32.
doi: 10.11883/1001-1455(2010)01-0027-06
Abstract:
Abstract:BytakingtheblastingexcavationoftheHongyanhenuclearpowerplantfoundationforexample, themechanicalpropertiesoftherockmasswereanalysedinthedifferentregionsofthenuclear islands,andthedamagedepthdifferencesoftherockmasswerediscussedfordifferentlayersunder excavation.Itwaspointedoutthatthecontrolmethodandsafetythresholdshouldbebroughtforward bythepracticalrockblasting.Basedonblastingvibrationsurveyingandsoundwavetestingconducted inconstructionsite,therelationshipbetweendamagezonesizeandpeakparticlevelocitywasinvestigatedfortherockmassatagivendistancefromthecentreofthechar ingarea,andthecorresponding empiricalformulawasestablished.Accordingly,thesafetythresholdofblastingvibrationwasgiven forthedifferentrockstratainnuclearislandsandthedifferentexcavationschemewasdetermined withthedifferentallowabledamagedepth.Resultsprovethatthemethodandthresholdareapplicable toholdthedamagedepthofrockandtoensuretheintegrityofthebedrockunderblastingexcavation.
Abstract:BytakingtheblastingexcavationoftheHongyanhenuclearpowerplantfoundationforexample, themechanicalpropertiesoftherockmasswereanalysedinthedifferentregionsofthenuclear islands,andthedamagedepthdifferencesoftherockmasswerediscussedfordifferentlayersunder excavation.Itwaspointedoutthatthecontrolmethodandsafetythresholdshouldbebroughtforward bythepracticalrockblasting.Basedonblastingvibrationsurveyingandsoundwavetestingconducted inconstructionsite,therelationshipbetweendamagezonesizeandpeakparticlevelocitywasinvestigatedfortherockmassatagivendistancefromthecentreofthechar ingarea,andthecorresponding empiricalformulawasestablished.Accordingly,thesafetythresholdofblastingvibrationwasgiven forthedifferentrockstratainnuclearislandsandthedifferentexcavationschemewasdetermined withthedifferentallowabledamagedepth.Resultsprovethatthemethodandthresholdareapplicable toholdthedamagedepthofrockandtoensuretheintegrityofthebedrockunderblastingexcavation.
2010, 30(1): 33-38.
doi: 10.11883/1001-1455(2010)01-0033-06
Abstract:
TheconventionalsplitHopkinsonpressurebar(SHPB)hassomelimitationswhenthespecimenissofttissue. The modificationsarenecessarytoensurethereliabilityofSHPBexperiment whichisbasedonone-dimensionalanduniformityassumptions.Pulseshaperswereusedtoachieve stressequilibriuminspecimensandconstantstrainrates.Thequartzcrystalforcetransducerswere introducedforcheckingthedynamicstressequilibriumandobtainingthestresssignals.Theadditional axialstressinducedbyradialinertiaeffectatthebeginningofthedynamicloadingwassubtractedwith anequation.Thestressstraincurvesformuscleswereobtainedatvariousloadingdirectionsandvariousstrainrates. Theresultsshowthatthestressstraincurvesisconcaveupwardasaviscoelasticmaterial. Theleastsignificantdifferencemethodisusedtoexplainthatmechanicalpropertiesofmuscle aresensitivetostrainrateandloadingdirection.Thecompressivestrengthalongthefiberdirectionis weakerthanthatalongtheperpendiculardirectionbecausefibersareinclinedtobucklingwhencompressionloadingsarealongfiberdirections
TheconventionalsplitHopkinsonpressurebar(SHPB)hassomelimitationswhenthespecimenissofttissue. The modificationsarenecessarytoensurethereliabilityofSHPBexperiment whichisbasedonone-dimensionalanduniformityassumptions.Pulseshaperswereusedtoachieve stressequilibriuminspecimensandconstantstrainrates.Thequartzcrystalforcetransducerswere introducedforcheckingthedynamicstressequilibriumandobtainingthestresssignals.Theadditional axialstressinducedbyradialinertiaeffectatthebeginningofthedynamicloadingwassubtractedwith anequation.Thestressstraincurvesformuscleswereobtainedatvariousloadingdirectionsandvariousstrainrates. Theresultsshowthatthestressstraincurvesisconcaveupwardasaviscoelasticmaterial. Theleastsignificantdifferencemethodisusedtoexplainthatmechanicalpropertiesofmuscle aresensitivetostrainrateandloadingdirection.Thecompressivestrengthalongthefiberdirectionis weakerthanthatalongtheperpendiculardirectionbecausefibersareinclinedtobucklingwhencompressionloadingsarealongfiberdirections
2010, 30(1): 39-44.
doi: 10.11883/1001-1455(2010)01-0039-06
Abstract:
TheparametersofJohnson-CookmodelweremodifiedforOFHCcopperbythedataofexpandingringexperiment. Thenumericalvelocityofringisconsistentwiththeexperimentalresult. Withthewidthofringincreasingunder8mm,thepeakvalueofvelocityincreases.However,while thewidthisover8mm,thepeakvalueofvelocityarrivesataconstant,buttheslopeofvelocityvaries withthewidthofring.Whilethewidthofringistwiceofthickness,thestressstateinexpandingring satisfiestheone-dimensionalstressassunption.Theresearchshowsthatthestressstateinexpanding ringisinfluencedbythesizeofringwhileexplosiveloading.
TheparametersofJohnson-CookmodelweremodifiedforOFHCcopperbythedataofexpandingringexperiment. Thenumericalvelocityofringisconsistentwiththeexperimentalresult. Withthewidthofringincreasingunder8mm,thepeakvalueofvelocityincreases.However,while thewidthisover8mm,thepeakvalueofvelocityarrivesataconstant,buttheslopeofvelocityvaries withthewidthofring.Whilethewidthofringistwiceofthickness,thestressstateinexpandingring satisfiestheone-dimensionalstressassunption.Theresearchshowsthatthestressstateinexpanding ringisinfluencedbythesizeofringwhileexplosiveloading.
2010, 30(1): 45-50.
doi: 10.11883/1001-1455(2010)01-0045-06
Abstract:
Aimattheproblemofannulusmulti-pointinitiationcircuitsappliedinmultimodeshaped charges,theLS-DYNAcodewasusedtoexploretheinitiationsynchronizationprecisionofsixpoints initiationcircuithowtoaffecttheparametersforthepenetratorsformation,suchasvelocityand length-diameterratio,bychangingthedelaypointsandtime.Thechangelawofacrossvelocitygrads wasobtained,whichwasthemainreasonthatcausedthepenetratorbend.Whenthedelaytimeis within200ns,thepenetratorcannotbendanditsformationparametersarenotchanged.Experimentalresultsshowtheexperimentaldataareinagreementwiththesimulations.
Aimattheproblemofannulusmulti-pointinitiationcircuitsappliedinmultimodeshaped charges,theLS-DYNAcodewasusedtoexploretheinitiationsynchronizationprecisionofsixpoints initiationcircuithowtoaffecttheparametersforthepenetratorsformation,suchasvelocityand length-diameterratio,bychangingthedelaypointsandtime.Thechangelawofacrossvelocitygrads wasobtained,whichwasthemainreasonthatcausedthepenetratorbend.Whenthedelaytimeis within200ns,thepenetratorcannotbendanditsformationparametersarenotchanged.Experimentalresultsshowtheexperimentaldataareinagreementwiththesimulations.
2010, 30(1): 51-57.
doi: 10.11883/1001-1455(2010)01-0051-07
Abstract:
Areactivepowerconcrete(RPC)shelterplatewasproposedtodevelopanewprotective technologyforresistingpenetrationweapons.Ballisticexperimentswiththeimpactvelocitiesof320~ 705m/swerecarriedoutbyusingsemi-armour-piercingprojectileswiththediameterof57mmtoinvestigatetheanti- penetrationcapacitiesofRPCshelterplateswithirregularbarriersontheirsurfaces comprisingyaw-inducinglayersandbasalplates.Someexperimentalresultswereobtainedsuchas failurecharacteristics,deflexionanglesand maximalpenetrationdepthsofprojectiles,andfailure modesoftargets.Andthesimplifiedcalculationalformulaforpenetrationdepthwasgiven.ThepenetrationpowersoftheprojectileswereweakenedobviouslybyirregularbarriersconsistingofRPCwith highstrengthandexcellenttoughness.Differentbucklingdeformationsandfracturesoccurredwhen projectilesimpactedonirregularbarriers.Thetrajectoriesweredeflexedandpenetrationdepthswere reducedgreatly.Thedeflexionanglesofprojectilesincreasedfirstlyanddecreasedsubsequentlywith theincreaseoftheimpactvelocity,themaximaldeflexionanglewas61.4inthecaseof505m/simpactvelocity. Therewerenotanyimpactcraterswithlargesizeoranyscabbingafterballisticexperiments, andtheintegralitiesoftargetsweregoodforasmallquantityofcracks.Thecalculationalresultsareingoodagreementwiththeexperimentaldata, andthesimplifiedformulaisfeasible.
Areactivepowerconcrete(RPC)shelterplatewasproposedtodevelopanewprotective technologyforresistingpenetrationweapons.Ballisticexperimentswiththeimpactvelocitiesof320~ 705m/swerecarriedoutbyusingsemi-armour-piercingprojectileswiththediameterof57mmtoinvestigatetheanti- penetrationcapacitiesofRPCshelterplateswithirregularbarriersontheirsurfaces comprisingyaw-inducinglayersandbasalplates.Someexperimentalresultswereobtainedsuchas failurecharacteristics,deflexionanglesand maximalpenetrationdepthsofprojectiles,andfailure modesoftargets.Andthesimplifiedcalculationalformulaforpenetrationdepthwasgiven.ThepenetrationpowersoftheprojectileswereweakenedobviouslybyirregularbarriersconsistingofRPCwith highstrengthandexcellenttoughness.Differentbucklingdeformationsandfracturesoccurredwhen projectilesimpactedonirregularbarriers.Thetrajectoriesweredeflexedandpenetrationdepthswere reducedgreatly.Thedeflexionanglesofprojectilesincreasedfirstlyanddecreasedsubsequentlywith theincreaseoftheimpactvelocity,themaximaldeflexionanglewas61.4inthecaseof505m/simpactvelocity. Therewerenotanyimpactcraterswithlargesizeoranyscabbingafterballisticexperiments, andtheintegralitiesoftargetsweregoodforasmallquantityofcracks.Thecalculationalresultsareingoodagreementwiththeexperimentaldata, andthesimplifiedformulaisfeasible.
2010, 30(1): 58-64.
doi: 10.11883/1001-1455(2010)01-0058-07
Abstract:
Basedonthenon-linearfinite-elementprocedureofLS-DYNA,theJohnson-Holmquist- Cook(JHC)modelwasadoptedtoinvestigatethedamageevolutionoftheconcreteneartheblasthole inthecasesofdifferentchargingstructuresanddifferentair-deckedratios.Thecalculationresultsfor threechargingstructuresshowthatthereisagradualchangefromcompression-shearfailuretotensile failurewiththeincreaseofair-deckedratioandthatdifferentair-deckedchargingstructurescanbeappliedtodifferentblastingpurposes. Forbenchblasting,thehighestutilizationratioofexplosionenergybelongstothetopair- deckedchargingstructure.Whentheair-deckedratioreaches40%,thefailuremodeoftheconcreteelementchangesfromcompression- shearfailuretotensilefailureinthemiddleoftheblasthole. Itisindicatedthatacertainreasonableair-deckedratioexistsanditcanbeused toimprovetheutilizationratioofblastingenergy.Forpresplittingblastingandsmoothblasting,the bestblastingeffectbelongstothemiddleair-deckedchargingstructure.Detonatingmannerscanaffect benchblastingmorestronglythanpresplittingblastingandsmoothblasting.
Basedonthenon-linearfinite-elementprocedureofLS-DYNA,theJohnson-Holmquist- Cook(JHC)modelwasadoptedtoinvestigatethedamageevolutionoftheconcreteneartheblasthole inthecasesofdifferentchargingstructuresanddifferentair-deckedratios.Thecalculationresultsfor threechargingstructuresshowthatthereisagradualchangefromcompression-shearfailuretotensile failurewiththeincreaseofair-deckedratioandthatdifferentair-deckedchargingstructurescanbeappliedtodifferentblastingpurposes. Forbenchblasting,thehighestutilizationratioofexplosionenergybelongstothetopair- deckedchargingstructure.Whentheair-deckedratioreaches40%,thefailuremodeoftheconcreteelementchangesfromcompression- shearfailuretotensilefailureinthemiddleoftheblasthole. Itisindicatedthatacertainreasonableair-deckedratioexistsanditcanbeused toimprovetheutilizationratioofblastingenergy.Forpresplittingblastingandsmoothblasting,the bestblastingeffectbelongstothemiddleair-deckedchargingstructure.Detonatingmannerscanaffect benchblastingmorestronglythanpresplittingblastingandsmoothblasting.
2010, 30(1): 65-69.
doi: 10.11883/1001-1455(2010)01-0065-05
Abstract:
Inordertoforecasttheoreticallythedeformationshapeofadeformabledirectionalwarhead onthegiveninitialconditions,thestructureofthedeformabledirectionalwarheadondeformingphase wassimplifiedasthesingle-layercylindricalshellwithadeformingcharge,andthecylindricalshell wasregardedasrigid-perfectlyplasticmaterial.A modelforanalyzingthedeformationshapeofthe deformabledirectionalwarheadwasestablishedbyusingthefive-plastic-hingedisplacementmodeof thecylindricalshellandtheprincipleofrigid-perfectlyplastic.Thetheoreticalresultsbythismodelagreewellwiththeexperimentalresults.
Inordertoforecasttheoreticallythedeformationshapeofadeformabledirectionalwarhead onthegiveninitialconditions,thestructureofthedeformabledirectionalwarheadondeformingphase wassimplifiedasthesingle-layercylindricalshellwithadeformingcharge,andthecylindricalshell wasregardedasrigid-perfectlyplasticmaterial.A modelforanalyzingthedeformationshapeofthe deformabledirectionalwarheadwasestablishedbyusingthefive-plastic-hingedisplacementmodeof thecylindricalshellandtheprincipleofrigid-perfectlyplastic.Thetheoreticalresultsbythismodelagreewellwiththeexperimentalresults.
2010, 30(1): 70-74.
doi: 10.11883/1001-1455(2010)01-0070-05
Abstract:
Theparametersoftheohmresistancemodelweredeterminedfromelectricexplosionexperimentsofsmallcopperfoilaccordingtotheexperimentalr sults.ByreferringtotheSesameEOSdata base,acalculationmethodforprocessoffoilelectricexplosionandflyerdrivingwasestablished,with whichEDF1.0programwasaccomplished.Thecalculatedprofilesofcurrent,voltageandflyervelocityreproducedtheprocessoffoilelectricexplosionandflyerdriving, andthecalculatedlinearrelation betweenflyervelocitiesandexplodingcurrentdensitieswasinaccordancewiththeelectricGurney model.
Theparametersoftheohmresistancemodelweredeterminedfromelectricexplosionexperimentsofsmallcopperfoilaccordingtotheexperimentalr sults.ByreferringtotheSesameEOSdata base,acalculationmethodforprocessoffoilelectricexplosionandflyerdrivingwasestablished,with whichEDF1.0programwasaccomplished.Thecalculatedprofilesofcurrent,voltageandflyervelocityreproducedtheprocessoffoilelectricexplosionandflyerdriving, andthecalculatedlinearrelation betweenflyervelocitiesandexplodingcurrentdensitieswasinaccordancewiththeelectricGurney model.
2010, 30(1): 75-79.
doi: 10.11883/1001-1455(2010)01-0075-05
Abstract:
Theshockinitiationthresholdundertheconditionof50%initiationprobabilitywasmeasuredforthecomposites, whichwerecomposedofnano-TATBandonesensitiveexplosive,underthe impactofathinplasticflayerplateacceleratedbyelectricallyexplodingfoils.Severalviewpointswere discussedontherelationshipbetweenthemicrostructuralparametersofnano-TATBandtheshockinitiationthresholdofitscomposites. Numericalmodelingofgranulatingprocesses,topographycharacterizationofmoldingpowdersurfacesandshockinitiationthresholdtestswerecarriedouttoexplore thedetonationprocessofthecompositeexplosive.Researchedresultsindicatethatthedistributionof sensitiveexplosiveparticlesonthesurfaceofcompositesmoldingpowderandthesizeofnano-gridding- TATBconglomerationmaybethemostimportantfactorofdeterminingtheshort-pulsepress andtimeactingonthesensitiveexplosiveparticles.
Theshockinitiationthresholdundertheconditionof50%initiationprobabilitywasmeasuredforthecomposites, whichwerecomposedofnano-TATBandonesensitiveexplosive,underthe impactofathinplasticflayerplateacceleratedbyelectricallyexplodingfoils.Severalviewpointswere discussedontherelationshipbetweenthemicrostructuralparametersofnano-TATBandtheshockinitiationthresholdofitscomposites. Numericalmodelingofgranulatingprocesses,topographycharacterizationofmoldingpowdersurfacesandshockinitiationthresholdtestswerecarriedouttoexplore thedetonationprocessofthecompositeexplosive.Researchedresultsindicatethatthedistributionof sensitiveexplosiveparticlesonthesurfaceofcompositesmoldingpowderandthesizeofnano-gridding- TATBconglomerationmaybethemostimportantfactorofdeterminingtheshort-pulsepress andtimeactingonthesensitiveexplosiveparticles.
2010, 30(1): 80-84.
doi: 10.11883/1001-1455(2010)01-0080-05
Abstract:
Anewmethodforvelocityprofiledataprocessingofupdatedinstantaneousdisplacementinterferometerisdevelopedinthispaper, whichmainlyaimsattheDPS(displacementpinsystem)in ChinaandPDV (photonDopplervelocimeter)inAmerica.Thismethodisbasedontheideaofrevivifyingmeasuredsignalbynon- linearregressionanalysis(NLRA),andthemainanalyzingprocessis presented.ComparingwiththetraditionalPick-Peaksmethodwhichisbasedondiscretedataprocessingidea, itcanobtainhigheraccuracyforvelocityprofileandhasastrongerabilitytodistinguishits details,especiallywhenitisusedtodealwithelasitc-plasticlowpressureimpactresponseofmaterials. Atlast,thecharacteristicsofthismethodarediscussedindetailbycalculatingthefree-surface velocityprofilesofSnand45steelundergoingalowpressureplanarimpactandmeasuredwithDPS.
Anewmethodforvelocityprofiledataprocessingofupdatedinstantaneousdisplacementinterferometerisdevelopedinthispaper, whichmainlyaimsattheDPS(displacementpinsystem)in ChinaandPDV (photonDopplervelocimeter)inAmerica.Thismethodisbasedontheideaofrevivifyingmeasuredsignalbynon- linearregressionanalysis(NLRA),andthemainanalyzingprocessis presented.ComparingwiththetraditionalPick-Peaksmethodwhichisbasedondiscretedataprocessingidea, itcanobtainhigheraccuracyforvelocityprofileandhasastrongerabilitytodistinguishits details,especiallywhenitisusedtodealwithelasitc-plasticlowpressureimpactresponseofmaterials. Atlast,thecharacteristicsofthismethodarediscussedindetailbycalculatingthefree-surface velocityprofilesofSnand45steelundergoingalowpressureplanarimpactandmeasuredwithDPS.
2010, 30(1): 85-90.
doi: 10.11883/1001-1455(2010)01-0085-06
Abstract:
Asamainenergyreleasefromunderwaterexplosion,blastcancauselocaldistortionofwarshipstructure, whereas,howthehullwillactagainstshockwavedeservesanadvancedresearch.The hullwassimplifiedasarigid,perfectlyplasticuniformbeamfloatingonwater.Theformulaofthe wallpressureonthewetsurfaceofthebeam wasattainedandmodifiedaccordingtotestdatawhere thefluid-structureinteractionwasconsidered.Inordertostudydynamicresponseofship-likebeams subjectedtounderwaterexplosionlocatedcloselyunderthemid-spanofthebeam,ahypothesiswas putforwardthatthesphericalshockwavespreadingonthehullwascomposedofaseriesofmoving, instantaneous,localplaneshockwaves,andtheresponseofthebeamsubjectedtosphericalshockwave wasequivalenttointegralresponsesduetoalltheplaneshockwaves.Basedonthissimplification,a theoreticalmethodwasproposedtodescribehowthebeamactedagainstunderwaterexplosionatany standoff.Finally,thetwomodelsofship-likebeamswereusedintheteststoverifytheproposed method.Resultsshowthatthetestdatabasicallyagreewiththoseoftheoreticalanalysis.Duringthe durationofshockwaveloadingonthebeam,themid-spanofthebeamtakesaback-and-forthmovement. Shockwavesplayasmallerroleinmakingbeamsbulkmovementthanthatincausinglocaldistortion.
Asamainenergyreleasefromunderwaterexplosion,blastcancauselocaldistortionofwarshipstructure, whereas,howthehullwillactagainstshockwavedeservesanadvancedresearch.The hullwassimplifiedasarigid,perfectlyplasticuniformbeamfloatingonwater.Theformulaofthe wallpressureonthewetsurfaceofthebeam wasattainedandmodifiedaccordingtotestdatawhere thefluid-structureinteractionwasconsidered.Inordertostudydynamicresponseofship-likebeams subjectedtounderwaterexplosionlocatedcloselyunderthemid-spanofthebeam,ahypothesiswas putforwardthatthesphericalshockwavespreadingonthehullwascomposedofaseriesofmoving, instantaneous,localplaneshockwaves,andtheresponseofthebeamsubjectedtosphericalshockwave wasequivalenttointegralresponsesduetoalltheplaneshockwaves.Basedonthissimplification,a theoreticalmethodwasproposedtodescribehowthebeamactedagainstunderwaterexplosionatany standoff.Finally,thetwomodelsofship-likebeamswereusedintheteststoverifytheproposed method.Resultsshowthatthetestdatabasicallyagreewiththoseoftheoreticalanalysis.Duringthe durationofshockwaveloadingonthebeam,themid-spanofthebeamtakesaback-and-forthmovement. Shockwavesplayasmallerroleinmakingbeamsbulkmovementthanthatincausinglocaldistortion.
2010, 30(1): 91-95.
doi: 10.11883/1001-1455(2010)01-0091-05
Abstract:
DOP(depthofpenetration)testswereperformedtostudytheballisticpenetrationcharacteristicsofconfinedAD95ceramictargetsbytungstenlongrods. Basedontheexperimentaldata,numericalsimulationsoftungstenlongrodspenetrationinto45steelandconfinedAD95ceramictargets werecompared,usingLS-DYNAsoftware.Thecomputationalresultsareingoodagreementwiththe experimentalresults.ThematerialconstantsofAD95ceramicwereobtainedfortheJH-2model.The responseofconfinedAD95ceramictargetswasinvestigatedbyfiniteelementsimulations.
DOP(depthofpenetration)testswereperformedtostudytheballisticpenetrationcharacteristicsofconfinedAD95ceramictargetsbytungstenlongrods. Basedontheexperimentaldata,numericalsimulationsoftungstenlongrodspenetrationinto45steelandconfinedAD95ceramictargets werecompared,usingLS-DYNAsoftware.Thecomputationalresultsareingoodagreementwiththe experimentalresults.ThematerialconstantsofAD95ceramicwereobtainedfortheJH-2model.The responseofconfinedAD95ceramictargetswasinvestigatedbyfiniteelementsimulations.
2010, 30(1): 96-100.
doi: 10.11883/1001-1455(2010)01-0096-05
Abstract:
BasedontheK- modelandtheimprovededdybreak-up(EBU)model,anewtheoretical modelwasestablishedtodescribethemethanejetdiffusioninducedbywellblowoutandthemethaneaircloudexplosion. Andthemethane-airclouddiffusionwasconsideredinthenew model.Byusing thenew model,theSIMPLEalgorithm wasadoptedtosolvedifferentialequations.Theformation processofthemethane-aircloudwasnumericallysimulatedtoinvestigatetheeffectsofdifferentignitionsonthemixturecloudexplosion. Theresultsshowthattheignitionlocationsandthegascloud concentrationsattheignitionpointscanaffectmarkedlythegascloudexplosion.Thenearertheignitionpointawayfromthegascloudcenterandthehigherthegasconcentrationattheignitionpoint, themoreintenselythegascloudexplodes.
BasedontheK- modelandtheimprovededdybreak-up(EBU)model,anewtheoretical modelwasestablishedtodescribethemethanejetdiffusioninducedbywellblowoutandthemethaneaircloudexplosion. Andthemethane-airclouddiffusionwasconsideredinthenew model.Byusing thenew model,theSIMPLEalgorithm wasadoptedtosolvedifferentialequations.Theformation processofthemethane-aircloudwasnumericallysimulatedtoinvestigatetheeffectsofdifferentignitionsonthemixturecloudexplosion. Theresultsshowthattheignitionlocationsandthegascloud concentrationsattheignitionpointscanaffectmarkedlythegascloudexplosion.Thenearertheignitionpointawayfromthegascloudcenterandthehigherthegasconcentrationattheignitionpoint, themoreintenselythegascloudexplodes.
2010, 30(1): 101-104.
doi: 10.11883/1001-1455(2010)01-0101-04
Abstract:
Loadingexperimentswerecarriedoutinalargeexplosionchamberunderdifferentconditions, andthestrainsandstressesatseveraltypicalpositionsweremeasuredbyanelectrictestmethod. Theexperimentalresultsshowthat:(1)Thestresspeakforthefirsttimeisthehighestatthe outersurfaceofthesphericalshellunderexplosionimpact,andthenthevibrationisbasicallydominatedinthestatesofalternatetensileandcompressivestresses, whichfallbelow100MPaimmediately justafter1~2cycles,sothevibrationfatigueofthesphericalshellcanbemarkedlyweakenedbythe soilaccumulation;(2)Thestrengthofthemodelmeetsthedesignrequirements;(4)Theareashowingthemaximumstressconcentrationisnearbythedischargeport;( 4)Theshapefactoroftheexplosivechargehasagreatinfluencetothestructuresafety.
Loadingexperimentswerecarriedoutinalargeexplosionchamberunderdifferentconditions, andthestrainsandstressesatseveraltypicalpositionsweremeasuredbyanelectrictestmethod. Theexperimentalresultsshowthat:(1)Thestresspeakforthefirsttimeisthehighestatthe outersurfaceofthesphericalshellunderexplosionimpact,andthenthevibrationisbasicallydominatedinthestatesofalternatetensileandcompressivestresses, whichfallbelow100MPaimmediately justafter1~2cycles,sothevibrationfatigueofthesphericalshellcanbemarkedlyweakenedbythe soilaccumulation;(2)Thestrengthofthemodelmeetsthedesignrequirements;(4)Theareashowingthemaximumstressconcentrationisnearbythedischargeport;( 4)Theshapefactoroftheexplosivechargehasagreatinfluencetothestructuresafety.
2010, 30(1): 105-108.
doi: 10.11883/1001-1455(2010)01-0105-04
Abstract:
Studyonthedynamicpropertyofmaterialsunderimpactloadingdependscloselyontheprogressofexperimentaltestingtechniques. Thepowergunwitha37-mm-diameterchamberwasusedas theloadingequipment,andK9glasswithinternalpreexisteddefectswaschosenasthesample.Under plateimpactingconditions,Dopplerpinssystem (DPS)testingtechnique,whosespaceandtimeresolutionswere127mand50psrespectively, wasadoptedtomeasurethevelocityhistoryoffreesurfaceslocatedindifferentplacesonsamplesfreesurface. Influenceofinternalpreexisteddefectson thevelocitysignalofsamplesfreesurfacewasanalyzedinbrief,andtheexperimentalmethodto studymaterialsdynamicpropertyfromthepointofmeso-microcosmicviewwasalsodiscussed.
Studyonthedynamicpropertyofmaterialsunderimpactloadingdependscloselyontheprogressofexperimentaltestingtechniques. Thepowergunwitha37-mm-diameterchamberwasusedas theloadingequipment,andK9glasswithinternalpreexisteddefectswaschosenasthesample.Under plateimpactingconditions,Dopplerpinssystem (DPS)testingtechnique,whosespaceandtimeresolutionswere127mand50psrespectively, wasadoptedtomeasurethevelocityhistoryoffreesurfaceslocatedindifferentplacesonsamplesfreesurface. Influenceofinternalpreexisteddefectson thevelocitysignalofsamplesfreesurfacewasanalyzedinbrief,andtheexperimentalmethodto studymaterialsdynamicpropertyfromthepointofmeso-microcosmicviewwasalsodiscussed.
2010, 30(1): 109-112.
doi: 10.11883/1001-1455(2010)01-0109-04
Abstract:
Anexperimentalapproachwaspresentedtoinvestigatedynamiccompressivebehaviorsof softmaterialsbyasplitHopkinsonpressurebar(SHPB)setupwithlateralconfinement.Inthedynamicexperiments, thespecimenwasconfinedinathin-walledmetallicsleeveandloadedaxiallybya splitHopkinsonpressurebar.Theradialstressandstrainofthespecimenwasobtainedbythecircumferentialstrainattheouterwallofthesleeve. BycombiningthesignalsrecordedbythetwogaugesontheHopkinsonpressurebar, thehydrostaticpressure-volumeevolutionofthespecimenwasachieved. Additionaldynamiccompressionexperimentswereconductedonpolymericfoam materialsby theabovemethod.Experimentalresultsdisplaythatthepresentedmethodcanbeusedtomeasurethe volumecompressioncharacteristicsofsoftmaterials.
Anexperimentalapproachwaspresentedtoinvestigatedynamiccompressivebehaviorsof softmaterialsbyasplitHopkinsonpressurebar(SHPB)setupwithlateralconfinement.Inthedynamicexperiments, thespecimenwasconfinedinathin-walledmetallicsleeveandloadedaxiallybya splitHopkinsonpressurebar.Theradialstressandstrainofthespecimenwasobtainedbythecircumferentialstrainattheouterwallofthesleeve. BycombiningthesignalsrecordedbythetwogaugesontheHopkinsonpressurebar, thehydrostaticpressure-volumeevolutionofthespecimenwasachieved. Additionaldynamiccompressionexperimentswereconductedonpolymericfoam materialsby theabovemethod.Experimentalresultsdisplaythatthepresentedmethodcanbeusedtomeasurethe volumecompressioncharacteristicsofsoftmaterials.
