简介:ADAMS/Aircraft模块是我所创建飞机虚拟样机的软件之一,我们通过该软件建立一些起落架模型,进行了落震分析、动画模拟仿真,计算结果与其他工程软件计算结果吻合。
简介:Inthemidseventiesanewpropulsorforaircraftwasdesignedandinvestigated-theso-calledPROPFAN.Withregardtothetotalpressureincrease,itrangesbetweenaconventionalpropellerandaturbofanwithveryhighbypassratio.Thisnewpropulsionsystempromisedareductioninfuelconsumptionof15to25%comparedtoenginesatthattime.Alotofpropfans(HamiltonStandard,USA)withdifferentnumbersofbladesandbladeshapeshavebeendesignedandtestedinwindtunnelsinordertofindanopimuminefficiency,Fig.1.ParalleltothisdevelopmentGE,USA,madeadesignofacounterrotatingunductedpropfan,theso-calledUDF,Fig.2.Aprototypeenginewasmanufacturedandinvestigatedonanin-flighttestbedmountedattheMD82andtheB727.Sincethattimetherehasnotbeenanyfurtherdevelopmentofpropfans(exceptAN70withNK90-engineUkraine,whichismoreorlessapropellerdesign)duetorelativelylowfuelpricesandtechnicalobstacles.Onlytechnicalprogramsindiferentcountriesarestillgoingoninordertoprepareadatabasefordesigningcounterrotatingfansintermsofaeroacoustics,aerodynamicsandaeroelasticities.InDLR.Germany,alotofexperimentalandnumericalworkhasbeenundertakentounderstandthephysicalbehaviouroftheunsteadyflowinacounterrotatingfan.
简介:Toutilizingthecharacteristicofradarcrosssection(RCS)ofthelowdetectableaircraft,aspecialpathplanningalgorithmtoeludingradarsbythevariableRCSispresented.ThealgorithmfirstgivestheRCSchangingmodeloflowdetectableaircraft,thenestablishesathreatmodelofaground-basedairdefensesystemaccordingtotherelationsbetweenRCSandtheradarrangecoverage.Bythenewcostfunctionsoftheflightpath,whichconsiderbothfactorsofthesurvivalprobabilityandthedistanceoftotalroute,thispathplanningmethodissimulatedbasedontheDijkstraalgorithm,andtheplannedroutemeetstheflightcapacityconstraints.Simulationresultsshowthatusingtheeffectivepathplanningalgorithm,thelowdetectableaircraftcangivefullplaytoitsownadvantageofstealthtoachievethepurposeofsilentpenetration.
简介:Corrosionisoneoftheimportantstructuralintegrityconcernsofagingaircraft,anditisestimatedthatasignificantportionofairframemaintenancebudgetsisdirectedtowardscorrosion-relatedproblemsforbothmilitaryandcommercialaircraft.Inordertobetterunderstandhowenvironmentalfactorsinfluencethecorrosiondamageinitiationandpropagationonaircraftstructureandtopredictpre-corrosiontestpiecesoffatiguelifeandstructuralintegrityofaneffectiveapproach,thispaperuses...
简介:Accurateaerodynamicmeasurementsinthehypersonicflowoflargeaircraftmodelsintunnelshavepracticalsignificance,butposeasignificantchallenge.Novelaerodynamicforcemeasurementmethodshavebeenproposed,butlacktheoreticalsupport.Theformsoftheforcesignalstechniquesforsignalprocessingandcalculationofaerodynamicsareespeciallyproblematic.Atheoreticalstudyisconductedtoinvestigatethedynamicpropertiesbasedonmodelsofthedraw-rodsystemandslenderrods.Theresultsindicatethattheinertiaitemcanbeneglectedintherodgoverningequation;further,thesolutionsshowthatthesignalsofeachrodareacombinationofaerodynamicsignals(withaconstantvalue)andsinesignals,whichcanbeverifiedbyexperimentalshocktunnelresults.Signalprocessingandaerodynamicscalculationtechniquesarealsofoundtobeachievableviatheflatpartofthesignals.
简介:Duetothedefectsofcurrentaircraftproductconfigurationtechnology,suchasthegapbetweenproductdesignandcustomers’requirements,thelowconfigurationefficiencyandetc.acustomer-orientedproductconfigurationsolutionofaircraftwasproposedinthispaper.Basingonadeepinvestigationintothemarketandthestructureoftheaircraft,thispaperproposedamethodofdividingandcreatingtheaircraftoptions,inwhichwesetupoptionalconstraintstomeetthedemandofconfigurationandthenoptimizedtheconstraintalgorithm.Thisworkcanhelptorealizetheoptimumassociationbetweentheaircraftoptionsandmodules.Basingonaresearchoncustomerdemand,Thepaperestablishedacustomerdemandmodelandamappingrelationshipwhichexistsbetweencustomerdemandandaircraftoptions,Itcanalsohelptomakeagreatcontributiontobuildcustomerpersonalizeddemandoftheaircraftconfigurationprocessandtheaircraftconfigurationlibrary.
简介:Athree-dimensionalglobalchemistrytransportmodel(OSLOCTM2)isusedtoinvestigatetheimpactofsubsonicaircraftNOxemissiononNOzandozoneoverChinaintermsofayear2000scenarioofsubsonicaircraftNOxemission.TheresultsshowthatsubsonicaircraftNOxemissionsignificantlyaffectsnorthernChina,whichmakesNOxat250hPaincreasebyabout50pptvwiththehighestpercentageof60%inJanuary,andleadingtoanozoneincreaseof8ppbvwith5%relativechangeinApril.TheNOxincreaseismainlyattributedtothetransportprocess,butozoneincreaseisproducedbythechemicalprocess.TheNOxincreasesbylessthan10pptvbyvirtueofsubsonicaircraftNOxemissionoverChina,andozonechangeslessthan0.4ppbv.WhensubsonicaircraftNOxemissionoverChinaisdoubled,itsinfluenceisstillrelativelysmall.
简介:Inordertoassurequalityandcontrolprocessinthedevelopmentoftheaircraftcollaborativedesignsoftware,amaturityassessmentmodelisproposed.Therequirementsdesigning—houseofqualityisdesignedtoevaluatethematuritydegreeofthesolution,andtheevaluationresultscanhelptomanageandcontrolthedevelopmentprocess.Furthermore,afuzzyevaluationmethodbasedontheminimumdeviationisproposedtodealwiththefuzzyinformation.Thequantitativeevaluationresultofthematuritydegreecanbecalculatedbyoptimizingthesemanticdiscountfactoraimfortheminimumdeviation.Finally,thismodelisillustratedandanalyzedbyanexamplestudyoftheaircraftcollaborativedesignsoftware.
简介:Amethodologyisimplementedtofindtheoptimumreducedweightconfigurationdesignofanoperatingstructureofacivilaircraftverticaltailfin.FE(finiteelement)basedtopologyoptimizationisexecutedtofindtheoptimummaterialdistributionofinitialdesignspaceofribbymaximizingthestiffness.Loadspertinenttotheoperatingandgroundconditionsareestimatedandapplied,consideringtheorientationofstructuralassemblymembersandbuilt-insupportsofferedinthemainstructure.Manufacturingconstraintsareincorporatedintotheoptimizationlooptogeneratepragmaticandmanufacturabledesignconfiguration.ThetopologicallyoptimizedconfigurationisthenconvertedtoCADviabledesignthroughdatareductionandsmoothingbyconvertingtoISO-surfaces.Amethodologyisalsodevisedtomodifythetopologicaloptimizedvoidsandmateriallayoutpreciselywithsplinesandfilletstoconstructmanufacturablefeaturesandavoidstressconcentrations.Theresultingnoveldesignproposalisthenanalyzedandvalidatedagainststipulatedloads,constraintsandotherdesignneeds.Resultsvalidatethenewdesignproposalasmorereliable,havingreducedweightandenhancedstructuralperformance.
简介:WiththevigorousdevelopmentofequipmentmanufacturingindustryinChina,higherrequirementstotheequipmentsupportabilityareputforward.Howtoevaluatethesupportabilityofequipments(especiallytheaviationequipment-aircraft)objectivelyandcorrectlyistheproblemtobesolvedinthedevelopmentofaviationequipmentsconstruction,demonstrationandbattleapplication.Aimedattheneedsofthesupportabilityanalysisofcomplexequipmentsystems-aircraft,amodelofaircraftsupportconceptevaluationbasedonDEA(dataenvelopmentanalysis)andPCA(principalcomponentanalysis)isproposed.Themodelisusedtoevaluateacertainaircraftsupportconcept.Theprocessandtheresultsofevaluationshowthatproposedmodelisfeasibleandeffective.Themodelissuitableforadvancedaircraftsupportconceptevaluation.Thefeasibilityandeffectivenessoftheproposedmodelisverifiedbytheanalysisoftheevaluationresults.Thismethodisapplicabletotheevaluationofaircraftsupportconcepts.