简介：ＳｏｌｉｄＭｏｄｅｌｉｎｇＥｒｏｒ：ＡｎａｌｙｓｉｓａｎｄＣｏｍｐｅｎｓａｔｉｏｎ①ＸｕＺｈｉｇａｎｇＨｕａｎｇＫｅｚｈｅｎｇＡｉＸｉｎｇＳｈａｎＬｉａｎｙｅＣｏｌｅｇｅｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＳｈａｎｄｏｎｇＵｎｉｖｅｒｓｉ...

简介：AgingofasolidcompositepropellantcontainingHTPB/AP/ALwasperformedinordertovalidatetheconformanceoftheacceleratedagingdatatotheArrheniuslaw.Themainobjectiveoftheworkwastoexaminetheinfluenceoftheaziridinebondingagentsfamilyonthepropellantaging.Agingofthepreparedpropellantsampleswasconductedasfollows:1.Foursamples,onefreeofbondingagents,andthreecontainingaziridinebasedbondingagentsMAPO,HX-752,MAT4wereagedat65°C.2.AnotherfoursamplesbasedonHX-752,MAT4withdifferentcuringagentswereagedat65°C.Themeasuredmechanicalpropertiesofthefreebondingagentpropellantsampleswereveryfarfromthespecificationsandthisillustratestheimportanceofthebondingagentsinboththepreparationandtheagingphases.Thepreparedbondingagent"MAT4"gaveremarkableimprovementsofthemechanicalpropertiescomparingwithHX-752andMAPO.Theaziridinebondingagentsfamilyinhibitedtherateofdecompositionofthepropellantduringtheagingperiodsandsupportedthepropellantmatrixagainstdecompositionattheelevatetemperatures.UsingofHMDIascuringagentgaveslightbettermechanicalpropertiestotheIPDI.

简介：Theballisticpropertiesofalowsolidloadingcompositesolidpropellantfamily(Butalites)wasstudiedexperimentallybyusingpropellantformulationsbasedonhydroxy-terminatedpolybutadienepre-polymer(HTPB)asfuelbindermainbackbone,monoandbi-modalsystemammoniumperchlorateoxidizer(AP),copperchromite(CC)asburningrateacceleratorandaluminumpowder(Al)asmetallicfuel.HigherpressuresandAPcontentsaswellassmallerAPparticlesizewerefoundtoincreaseburningrate.ThesamebehaviorverifiedwithAlandCCaddition.AsignificantincreaseofburningratewasrecordedwhenCCaddedtothealuminizedformulationscomparedwiththenon-aluminizedofthesameoxidizersolidloadingandparticlesize.

简介：Thecombustion(ballistic)propertiesofahighsolidloadingcompositesolidpropellantfamily(Butalites)wasstudiedexperimentallybyusingpropellantformulationsbasedonhydroxy-terminatedpolybutadienepre-polymer(HTPB)asafuelbindermainbackbone,bi-modalsystemammoniumperchlorateoxidizer(AP)andaluminumpowder(Al)asmetallicfuel.Burningratesweredoubledatvariouspressures,whensolidsloading(APand17%Al)wereincreasedfrom80to88%andthemeasuredcharacteristicvelocityvalueswereincreasedbyabout100m/sec.Thepressureexponent(n)valueswerelowerwith80-85%solidsloading.Theburningrateswereincreasedbyabout2-5%whencomparingthedataobtainedbystaticfiringwiththoseobtainedbythestrandburnermethod.

简介：Atime-resolvednumericalcomputationalapproach,involvingthecombustionofdouble-basepropellantisperformedonthermalprotectionmaterialforSRMnozzle.AnimplicitNavier-StokesSolverisselectedtosimulatetwo-dimensionalaxial-symmetricunsteadyturbulentflowofcompressiblefluid.ThegoverningequationsarediscreditedbyusingthefiniteVolumemethod.S-Aturbulencemodelisemployed.CFDschemeisimplementedtoinvestigatethetemperaturedistributioncausesatnozzlethroatinsertscompositematerial.DifferentparametershavebeenselectedfortheanalysistovalidatethetemperaturevariationinthethroatinsertsandbakingmaterialofSRMnozzle.TheadvancedSRMnozzlecompositematerialisalsocharacterizedforthehighthermostabilityandhighthermomechanicalcapabilitiestomakeitmorereliable,simplerandlighter.

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简介：A3D-viewishelpfultoinstantlygraspwhatispresentedinadrawing.Thereexistavarietyofwaystopresentthesamepartwith3D-views.Tofacilitatethechoiceofanoptimumoneamongthem,theworkdividescompositesolidmodelsintothreecategories,soastoconveytheoriginalityofdesignconciselyandaccuratelybyusingtheleast'engineeringlanguage'.

简介：Wepresentthesolidmodeleditdistance(SMED),apowerfulandflexibleparadigmforexploitingshapesimilaritiesamongstCADmodels.ItisdesignedtomeasurethemagnitudeofdistortionsbetweentwoCADmodelsinboundaryrepresentation(B-rep).Wegivetheformaldefinitionbyanalogywithgrapheditdistance,oneofthemostpopulargraphmatchingmethods.Toavoidtheexpensivecomputationalcostpotentiallycausedbyexactcomputation,anapproximateprocedurebasedonthealignmentoflocalstructuresetsisprovidedinaddition.Inordertoverifytheflexibility,wemakeintensiveinvestigationsonthreetypicalapplicationsinmanufacturingindustry,anddescribehowourmethodcanbeadaptedtomeetthevariousrequirements.Furthermore,amultilevelmethodisproposedtomakefurtherimprovementsofthepresentedalgorithmonbotheffectivenessandefficiency,inwhichthemodelsarehierarchicallysegmentedintotheconfigurationsoffeatures.ExperimentresultsshowthatSMEDservesasareasonablemeasurementofshapesimilarityforCADmodels,andtheproposedapproachprovidesremarkableperformanceonareal-worldCADmodeldatabase.