动车组车体结构、车端连接（英文）讲解

西南交通大学雅万高铁运维人员培训2022年10月Lecturer：ShaoyiZHOUEMUbodystructure、Vehicleendconnectiondevices1.2.EMUbodystructuredesignKCIC400AFEMUbodystructure3.Vehicleendconnectiondevices1EMUbodystructuredesignInordertomeettheapplicationrequirementsofhigh-speedtrains,thedesignoftheEMUisdifferentfromthecurrentdesignofordinarypassengercars.ThestructuraldesignoftheEMUcarbodymainlyincludes:streamlinedcarbodystructuredesign,lightweightdesignofthecarbody,andsealingandsoundinsulationdesignofthecarbody.2Streamlinedbodystructuredesign

Withtheincreaseoftherunningspeedofthehigh-speedtrain,thedynamiceffectofthesurroundingairaffectsthetrainandtherunningperformanceofthetrainontheonehand;atthesametime,theaerodynamicphenomenoncausedbythehigh-speedoperationofthetrainalsoaffectsthesurroundingenvironment,whichistheaerodynamicproblemofthehigh-speedtrain.2.1ForcesandmomentsoftrainaerodynamicsTheforcesandmomentsexperiencedbytheEMUduringhigh-speedoperationinclude:airresistanceforce,liftforce,lateralforce,aswellaslongitudinalswingmoment,torsionmomentandrollingmoment.AirflowRollingmomentAirresistanceforceLongitudinalswingmomentSwingmomentLiftforceLateralforce2.1.1AirresistanceTherunningresistancesustainedbytheEMUismainlycomposedofairresistanceandmechanicalresistance(i.e.wheel-railfrictionresistance,frictionresistanceofrollingpartssuchasbearings,etc.).Theapproximateexpressionofairresistanceis:WhereCx:coefficientofairresistance,ρ:airdensity,V:trainspeed,A:traincross-sectionalareaTheairresistanceisproportionaltothesquareofvelocity,whilethemechanicalresistanceisproportionaltovelocity.2.1.1AirresistanceWhenthespeedoftheEMUis100km/h,theairresistanceandthemechanicalresistanceeachaccountforhalf;Whenthespeedisincreasedto200km/h,theairresistanceaccountsfor70%,andthemechanicalresistanceaccountsforonly30%;Whenthespeedreachat250km/h,theairresistanceaccountsformorethan80-90%ofthetotalresistance.Therefore,reducingtheairresistanceoftheEMUisofgreatsignificancetoachievehigh-speedoperationandenergysaving.Thebodyshapeneedstobeoptimizedtoreduceairresistanceasmuchaspossible.Theroofshapeshouldbedesignedasacirculararctoreduceairresistance.2.1.2LiftforceThepartialpressureonthesurfaceoftheEMUisdefinedaspositivewhenitishigherthanthesurroundingairpressure,otherwise,itisdefinedasnegative.Asawhole,whetherthevehicleexperiencespositive(upward)ornegative(downward)liftforcedependsonwhetherthecumulativesurfacepressuresofallsectionsofthevehiclearepositiveornegative.Theliftforceisalsoproportionaltothesquareofthetrainspeed.Positiveliftforcewillreducethecontactpressureofthewheelandrail,whichwillhaveanimportantimpactonthetractionanddynamicperformanceofthetrain.Inordertoreducetheliftforceofthetrain,thecross-sectionalshapeofthecarbodyisdesigned:thesideofthecarbodyisflat,andtheupperandlowerpartsaregraduallyinwardlyinclined.2.1.3LateralforceWhentheEMUencounterslateralwind,thevehiclewillbeaffectedbythelateralforceandmoment.Whenthewindloadreachesatacertainlevel,thelateralforceanditsrollingmomentandtorsionalmomentwillaffecttheoverturningsafetyofthevehicle.Theapproximateexpressionoflateralforceis:WhereCD:Sidedragcoefficient,V:Trainspeed,A:TrainsideprojectedareaInordertoreducelateralforcesandmoments,thecornersoftheroofandthesidesofthecarbodyarecompletelyrounded.2.1.4TheexteriordesignoftheEMUbodyIntotal,thedesignofthecross-sectionalshapeoftheEMUbodyhasthefollowingcharacteristics:Thecross-sectionofthebodyisdrum-shaped,thatis,theroofisinacirculararcshape,thelowerpartofthesidewallslopesinward(~5°)andtransitionstothechassisinacirculararc,andtheupperpartofthesidewallslopesinward(~3°)andtransitionsinacirculararctothebottomframe.roof.Thepictureshowsthecross-sectionalshapeofthebodyoftheGermanICEEMU.Thiscannotonlyreducetheairresistance,butalsohelptoalleviatetheeffectsofthetraincrossingpressure,thelateralresistanceandtherollingmoment.2.1.4TheexteriordesignoftheEMUbodyIntotal,thedesignofthecross-sectionalshapeoftheEMUbodyhasthefollowingcharacteristics:Theshapeofthebottomofthevehiclehasagreatinfluenceontheairresistance.Inordertoavoidtheexposureoftheequipmentunderthefloor,askirtthatmatchesthecross-sectionalshapeofthevehiclebodyisusedtocovertheequipmentunderthevehicletoreducetheairresistanceandpreventsandcausedbyhigh-speedoperation.Thestonehitstheequipmentunderthecar.Thebodysurfaceissmoothandflatwithminimalprotrusions.Forexample,thesidedooradoptstheplugtype,thearmrestisbuilt-intype,andthefootpedalismadeintoaflaptype,sothatthesidecanbewrappedwhenitisclosed.Alargerubberwindshieldshouldbeusedattheconnectionbetweenthetwovehicles,whichshouldbekeptflushwiththebodytoavoidtheformationofairvortex.2.2SurfacepressureoftrainsforEMUsmeetingThemagnitudeofthemaximumpressurepulsationgeneratedwhenthetrainsmeetisanindextoevaluatetheaerodynamicshapeofthetrain.Whenatrainmeetsanotherstationarytrain,andwhentwotrainsmovingoppositeeachotherataconstantorunequalspeed,pressurewillbeinducedonthesidewallonthesideofthestationarytrainandthetwooppositemovingtrainswaves(pressurepulses).Thisisduetotheextrusionoftheairbytherelativelymovingtrainhead,whichsweptacrossthesidewalloftheothertrainthatintersectswithit,causingtheairpressureonthesidewallbetweenthetrainstofluctuategreatly.2.2SurfacepressureoftrainsforEMUsmeetingTheexperimentalresearchandsimulationshowthatthemagnitudeofthepressurefluctuationoftheEMUmeetingtrainisrelatedtothefollowingfactors:Withthegreatincreaseofthemeetingspeed,theintensityofthepressurewaveofthemeetingwillincreasesharply;Withtheheadlengthslendernessratioγbeing2.5,thepressurewaveamplitudenearlydoubleswhenthemeetingspeedincreasesfrom250km/hto350km/h.2.2SurfacepressureoftrainsforEMUsmeetingTheexperimentalresearchandcalculationshowthatthemagnitudeofthepressurefluctuationoftheEMUmeetingtrainisrelatedtothefollowingfactors:Theamplitudeofthepassingvehiclepressuredecreasessignificantlyandapproximatelylinearlywiththeincreaseoftheheadslendernessratio.InordertoeffectivelyreducetheintensityofthepressurewavecausedbythemeetingoftheEMU,theheadoftheEMUshouldbedesignedtobeslenderandstreamlined.TheamplitudeofthepressurefluctuationofthepassingtrainsdecreasessignificantlywiththeincreaseofthedistancebetweenthesidewallsofthepassingEMUs.Inordertoreducethepressurewaveofpassingtrainsanditsinfluence,thelinespacingoftherailwayshouldbeappropriatelyincreased.Speed(km/h)160200250300350Minimumlinespacing(m)4.24.44.64.85.02.2SurfacepressureoftrainsforEMUsmeetingTheexperimentalresearchandcalculationshowthatthemagnitudeofthepressurefluctuationoftheEMUmeetingtrainisrelatedtothefollowingfactors:Theamplitudeofthepassingvehiclepressureincreasessignificantlyandapproximatelylinearlywiththeincreaseofthepassingvehiclelength.Theamplitudeofthepassingvehiclepressuredecreasessignificantlywiththeincreaseoftheheightofthesidewall,butthemagnitudeofthedecreasedecreasesgraduallywiththeincreaseoftheheightofthesidewall.Whenhighandmedium-speedtrainsmeet,thepressurefluctuationofmedium-speedtrainsismuchlargerthanthatofhigh-speedtrains(generally1.8timeshigher).2.3ThesurfacepressureoftheEMUpassingthroughthetunnelWhentheEMUrunsinthetunnel,theairpressureinthetunnelwillfluctuatesharply,sothepressureonthesurfaceofthetrainalsochangesrapidlyandgreatly,whichiscompletelydifferentfromthesurfacepressuredistributionontheopenline.Theexperimentalresearchshowsthatthechangeofpressureamplitudeisrelatedtotrainspeed,trainlength,blockagecoefficient(theratioofthecross-sectionalareaofthetraintothecross-sectionalareaofthetunnel),andtheheadshapecoefficient(theslendernessratio,thatis,thelengthofthenose-shapedpartofthefrontofthecarandtherearofthecar.Itisrelatedtofactorssuchastheratioofthecross-sectionradiusoftheouterbody),andthefrictioncoefficientofthesideofthetrainandthesideofthetunnel,amongwhichtheblockingcoefficientandthespeedofthetrainaretheimportantinfluencingparameters.2.4EMUheadshapedesign

Forhigh-speedEMUs,thedesignoftheheadshapeofthetrainisveryimportant.Agoodheadshapedesigncaneffectivelyreducetherunningairresistance,thetrain’smeetingwavepressure,andeventuallysolvetheproblemsofrunningstability.2.4.1BasicrequirementsforheadshapedesignSomecountrieswithrelativelyearlydevelopmentofhigh-speedrailwayshaveclearlyputforwardtheirowntraindragcoefficientindicatorsthroughexperimentalresearchandtheoreticalcalculations.TakingtheGermanICEEMUasanexample,theairdragcoefficientsofthedrivingheadcaratthefrontandendofthetrainare0.17and0.19,respectively.SlendernessratioTheratioofthelengthofthenoseatthefrontendofthecartotheradiusofthebodysectionattherearofthecar.Thedragcoefficientoftheheadandtailcarsisdirectlyrelatedtotheslendernessratioofthestreamlinedhead.Theslendernessratiooftheheadofahigh-speedtrainisgenerallyrequiredtobeabout3ormore.2.4.2StreamlinedesignofEMUhead

Thecontourlineonthelongitudinalsymmetryplaneoftheheadmustmeettheconditionsofthecabheadroom,thegeometricsizeofthefrontwindow,theglassshape,andthelookout.Onthisbasis,theverticalheightofthecontourlineisreducedasmuchaspossible,sothattheheadtendstobeflat,whichcanreducethepressureshockwaveandimprovetheinfluenceofthetailvortex.Atthesametime,thenoseconepartattheendisdesignedintoanovalshape,whichcanreducetheairresistanceofthetrainwhenitisrunning.2.4.2StreamlinedesignofEMUheadWhendesigningthemaximumoutlineshapeofthetopview,theheadmustfirstmeetthewidthrequirementsofthedriver'scab,andthendesignthenoseconepartintoataperedovalshape.Inthisway,itisnotonlybeneficialtoreducethecross-trainpressurewaveandimprovetheinfluenceofthetailvortex,butalsotakeintoaccounttheellipsoidshapethatisbeneficialtoreducetheairresistance.Agroove-shapeddeflectorshouldalsobedesignedtoguidetheairflowtobothsidesofthefrontofthecar.Afterthedesignofthemainmoldinglineiscompleted,theshapeoftheheadmustbestrictlytangenttotheshapeofthebody;intheshapeofthehead,thetwoarbitrarilyselectedsurfacesshouldalsobestrictlytangenttoensurethesmoothnessoftheshapeofthehead.Itnotonlyreducestheairresistance,butalsoreducestheamplitudeofthetrainintersectionpressure.3LightweightDesignThepurposeofadoptinglightweightdesign:Reducedvehicleweightcanreducerunningresistanceandsavetractionandbrakingpower(energy);Itcanreducethepressureonthetrack,therebyreducingthewearofthewheelandtrack;Reducevehicledamagetolines;Directlyreducetheconsumptionofvehiclematerials,etc.Themainwaystoachievelightweightstructure:usingnewmaterials;Optimizingthestructuraldesign.3.1LightweightmaterialsforcarbodyLightweightmaterialsusedinEMUsinclude:weatheringresistantsteelStainlesssteelAluminumalloyAtpresent,themostcommonmethodforlightweightdesignofcarbodystructureistousealuminumalloymaterials.ChineseEMUs,theirbodymaterialsandweightEMUtypeBodyMaterialCarbodyweight（t）CRH1Stainlesssteel11.9~12.5CRH3Aluminumalloy113.2DifficultiesintheapplicationofaluminumalloymaterialsComparedwithsteelmaterials,theapplicationofaluminumalloyshasthefollowingdifficulties:Aluminumalloyjoiningisdifficult,andtheuseofautomaticweldingimprovesproductionqualityandefficiency;TheYoung'smodulusandspecificgravityofaluminumalloysareabout1/3ofthoseofsteel,sotheweightofaluminumalloycarbodiescanbemuchlighter.However,theequivalentbendingstiffnessofthecarbodystructureisalsoreducedto1/3,whichincreasesthedeflectionofthecarbody,therebyaffectingthebasicperformanceofthevehicle(especiallytheridecomfort).Inordertomaintaintherigidityofthevehiclebody,itisnecessarytoexpandthecross-sectionalsecondarymomentoftheconstituentmaterial.3.3BodyformsusingAluminiumalloyLarge-scalehollowextrudedaluminumprofileweldedstructureAluminiumalloybodystructureadoptingtheformofaviationskeletonHybridstructureoflargehollowextrudedaluminumprofilesandopenprofiles

3.4BodystructuredesignMono-shellbodystructureAtfirst,extrudedprofileswerethemainstreamofmono-shellstructuresusingthinprofiles.Themono-shellstructureislightinweight,buthaslowcross-sectionalstiffness.Therefore,itisnecessarytousereinforcingmaterialstomeetthestrengthrequirementsofthevehiclebody.singleshellreinforcement3.4BodystructuredesignDouble-shellbodystructureAstructurewithahollowprofileasthecenteriscalledadouble-shellstructure.Comparedwiththemono-shellstructure,thedouble-shelloneisheavier.Duetothehighout-of-planestiffnessofthehollowmaterial,thereinforcingmaterialthatmustbeusedinthesingle-shellstructurecanbeomitted,therebyreducingthenumberofmaterialsandreducingthecost.3.4BodystructuredesignThedouble-shellstructurecanmeetthehighrigidityrequirementsofthecarbodyandattenuatenoisetransmission,therebyimprovingtheridecomfortinthecar;greatlyreducingthenumberofpartsandexpandingthescopeofautomatedwelding,therebyimprovingproductionqualityandreducingmanufacturingcosts.Excessivepursuitofthelightweightofhigh-speedEMUswilladverselyaffectridecomfortandtrainaerodynamicperformance.Inrecentyears,duetomoreemphasisonridecomfort,thebodystructureisnotsimplypursuinglightweight,butreasonablycontrollingtheweightofthebodystructure.Thedouble-shellstructureiscurrentlythebesthigh-speedEMUcarbodystructure,whichcantakeintoaccountbothlightweightandridecomfort.4.ThesealingdesignofthecarbodyEffectsofpressurewavesonpassengercomfortThefluctuationofthepressureoutsidethecarwillbereflectedinthecabin,makingthepassengersfeeluncomfortable,thelightonewilloppresstheeardrum,theheavyonewillcausedizzinessandnausea,andevencausetheeardrumtorupture.Manycountrieshavesuccessivelyconductedresearchontheimpactofpressurewavesonpassengercomfort,andtheresultsshowthat:Whenthereisnointersectingtrain,theairpressurechangesoutsidetheheadandtailcarsare:theheadissubjecttoapositivepressureofabout2.5KPa,andthetailisanegativepressureofabout2.0KPa;Whenthereareintersectingtrains,especiallywhenthetrainsmeetinthetunnel,theairpressureoutsidethetrainwillchangegreatly.Theairflowmeasurementresultsofthetrainenteringthetunnel:whenthespeedis200km/h,thepositivepressureattheheadis3.2KPa,andthenegativepressureatthetailis4.9KPa;whenthespeedis280km/h,thepositivepressureattheheadis3.9KPa,andthenegativepressureatthetailis5.5KPa.4.ThesealingdesignofthecarbodyEffectsofpressurewavesonpassengercomfortPressurevariationPhysiologicalphenomenonendurableStarttofeeluncomfortableVeryuncomfortableUpperlimitofbeinguncomfortable,starttopainintheearVerypainfulExtremelypainfulPossibleruptureofeardrumProbableruptureofeardrum4.ThesealingdesignofthecarbodyRequirementsforcarbodysealingperformanceChinarequiresinthe"InterimRegulationsonSealDesignandTestAppraisalof200km/handAboveSpeedClassTrains":Thesealingperformancetestafterthecompletionofthewholevehiclerequiresthatthetimetoreachthepressureinsidethevehiclefrom3600Pato1350Paisgreaterthan18s;Thesealingperformanceofthecarbodystructurerequiresthatthetimeforthepressuretodropfrom3600Pato1350Pamustbegreaterthan36s;Theformedwindows,doorsandwindshieldsshouldbeabletomaintaingoodsealingundertheaerodynamicloadof±4000Pa.4.ThesealingdesignofthecarbodyThesealingofthetrainneedstobeconsideredfromthebodystructureandcomponents.Atpresent,thesealingtechnologiesusedinhigh-speedtrainsaroundtheworldmainlyinclude:Thecarbodystructureadoptscontinuousweldingseamstoeliminateweldingairgaps;thepartsthatcannotbeweldedmustbesealedwithsealant.Usingfixedwindows,theassemblyprocessofthewindowsshouldensurethereliabilityanddurabilityoftheseal,andatthesametimeensurethatthewindowsshouldbeabletowithstandtheaerodynamicloadscausedbypressurewaves(China's"InterimRegulationsonHigh-speedTrainSealingTechnology").±6000Paaerodynamicload),willnotcausedeformationanddamage.Thesidedooradoptstheplugdoorwithgoodsealingperformance;theenddoorattheheadandthetailadoptstherubberstripthatcanbefilledwithcompressedair;therubberwindshieldisadoptedthroughthetyphoonshield,andthesealingproblematthecrossingplateshouldbehandledwell.4.ThesealingdesignofthecarbodyThesealingofthetrainneedstobeconsideredfromthebodystructureandcomponents.Atpresent,thesealingtechnologiesusedinhigh-speedtrainsaroundtheworldmainlyinclude:Theair-conditioningenvironmentalcontrolequipmentsetsuppressurecontrol:suchasinstallingpressureprotectionvalvesintheairinletandoutletofthepassengerroom,installinganexhaustfanwithathrottlevalveintheexhaustairduct,installingapressureprotectionfan,etc.,themainpurposeistoensurenormalventilation.Thegasalsoensuresthatthepressurechangeinthevehicleiswithinthelimit.Thewaterintoiletsandwashroomscannotbedirectlydischarged,butmustbedischargedtotheoutsideofthecarthroughsealingdevices;necessarysealingmeasuresshouldbetakenforthepipelinesandcableholesunderthestraight-throughcar.Beforeleavingthefactory,thevehiclemustpasstheairtightnessandwatertightnesstestofthewholevehicle.5SoundinsulationdesignofcarbodyNoisesourcesofhigh-speedtrainsWheel-railnoise(collision,friction);Thefrictiongeneratedbytheairflowingalongthesurfaceofthecarbodyandthefrictionsoundofthepantographandthecatenarywire;Theimpactsoundofwindshieldandothercomponents;Compressionwavesgeneratedbytrainsenteringandexitingtunnelsandnoisegeneratedbyreflectedwaves,etc.5SoundinsulationdesignofcarbodyIn-carnoisegenerallyconsistsofthefollowingcomponents:Thenoiseintroducedintothecarfromtheoutsideofthecarbodyisgenerallycalledairsound;Thestructuralvibrationoftheinnersurfaceofthevehiclecausedbyvariousreasons,especiallytheradiatedsoundgeneratedbythevibrationofthethin-walledstructure,isgenerallycalledstructuralvibrationnoise;Variousin-vehicleequipmentandsystems(suchasairconditioningandventilationsystems,varioustypesofpipes,etc.),asthenoisegeneratedbythevibrationsourceandsoundsource;Theabove-mentionedvarioustypesofnoisearecomposedofreverberationsoundformedbypropagationandreflectioninsidethecar.StandardlimitvaluesforinteriornoiseTheInternationalUnionofRailwaysstipulatesthatthenoiseinsidethepassengercarshouldbelessthan65dB(A).Inthetunnel,thenoisecanbetoleratedby5dB(A).Inaisles,toilets,thenoiselevelshouldnotexceed75dB(A).5SoundinsulationdesignofcarbodyInordertoreducethenoiseinthecar,ontheonehand,theintensityofthenoiseemittedbythenoisesourceshouldbeweakened,andontheotherhand,thesoundinsulationperformanceofthecarbodyshouldbeimproved.Measurestoreducetheintensityofnoiseemittedbynoisesources:Installingmufflersonwheelsanddevelopingelasticwheelscaneffectivelyreducewheel-railnoise;Theshapeofthecarbodyisdesignedtobestreamlined,andthesurfaceofthecarbodyisflatandsmooth,whichisconducivetoreducingthefrictionsoundbetweentheairandthecarbody;Adoptrubberwindshieldtoreduceimpactsound;Installamufflerontheairconditioningsystemtoreducethenoiseofthetractionmotorfanandthevibrationnoiseofthedrivedeviceandotherequipment.5SoundinsulationdesignofcarbodyMeasurestoimprovethesoundinsulationperformanceofthecarbody:Thedoublewallstructurecanincreasethesoundinsulationby4-5dB(A).Theso-calleddouble-layerwallreferstothemulti-layerstructuresuchasthefloor,sidewall,androof,etc.,whichareseparatedbyrubberpads.Improvethesoundinsulationperformanceofthecarbody;Painttheanti-vibrationdampinglayeronthesurfaceofthecarbodymetal(suchasthefloor),sothattheacousticvibrationofthesteelstructureisconvertedintoheatenergytodissipate,whichreducestheradiationofsoundwavesandthetransmissionofsoundwavevibration,therebyreducingthenoiseinthecar;Adoptdouble-layerwindowstoreducethenoiseintroducedintothecarfromtheside;Thehigh-molecularpolymermaterialwithgoodsoundabsorptioneffectisusedinthecar;Measurestoimprovetheairtightnessofthevehiclebodycanalsoplayaroleinsoundinsulation.Throughvarioussoundinsulationmeasures,thenoisevalueinthepassengercompartmentoftheFrenchTGV-Ahigh-speedtrainreaches66dB(A)whenthespeedreaches300km/h.1.2.EMUbodystructuredesignKCIC400AFEMUbodystructure3.Vehicleendconnectiondevice1OverviewofKCIC400AFEMUKCIC400AFEMUisapower-distributedelectricvehiclewithaspeedof350kilometersperhour.Itadoptstheconfigurationof4motorsand4trailers,andhasacapacityof601passengers.TC01/08:headcar,M02/07:second-classmotorcar,TP03/06:second-classtrailerwithtransformer,MH04:second-classmotorcarwithtoiletforthedisabled,MB05:diningseatcombinationcar.1OverviewofKCIC400AFEMUitemparameteritemparameterconfiguration4motors+4trailersbodymaterialAluminumalloyDesignlife(years)30Overalllengthofcarbody(m)~209Ambienttemperature(°C)-25~+40Maximumheightofvehiclebody(mm)4050Overallcapacity(t)51.2Maximumbodywidth(mm)3360Maximumaxleload(t)17Adapttoplatformheight(mm)1250Maximumtestspeed(km/h)385Maximumoperatingspeed(km/h)350minimumcurveradius(m)250Pantographdropheight(mm)

4436Autocouplercenterheight(mm)1000Middlecouplercenterheight(mm)9352StructureandappearancecharacteristicsofKCIC400AFEMUAccordingtothesimulationanalysisandwindtunneltest,thevariousheadshapeschemesareevaluatedandoptimizedfromtheaspectsofaerodynamicdrag,taillift,lateralforce,intersectionperformance,andaerodynamicnoise.KCIC400AFadoptsastreamlineddesign,andtheslendernessratiooftheheadshapeis3.22.Themeasuredresistanceataspeedof350km/his12.3%lowerthanthatofCRH380A;Thecrosssectionofthecarbodyisenlarged,theblockingratioisenlarged,andthesafetyfactorofairtightstrengthisincreasedfrom1.5to2.27;Thepantograph,air-conditioningandhigh-voltageequipmentadoptasunkensmoothdesigntoreduceairresistance.3BodystructureofKCIC400AFEMUThecarbodystructureismainlydividedintotwotypes:themiddlecarbodyandtheheadcarbody.Themiddlecarbodyiscomposedofunderframe,sidewall,roofandendwall,andtheheadcarbodyisprovidedwithadriver'scabstructure.Thecarbodystructureisweldedwiththelargehollowaluminumalloyprofilesofthefulllengthofthecarbody,whichisacylindricaloverallbearingstructure.KCIC400AFheadcaris27.2m,thelengthofthemiddlecaris25m,thewidthis3360mm,andtheheightoftherooffromtherailsurfaceis4050mm.3BodystructureofKCIC400AFEMUTheroofisthebaseoftheupperbodymemberandpantograph,etc.,andasmootharcroofstructureismadealongthebasicbodycross-sectionalshape.Itmustbeensuredthatthereisnopermanentdeformationundernormalmaintenanceworksuchasroofequipmentandworkerssittingontheground.Theinsideoftheroofpanelislinedwithsoundandthermalinsulation.Theunderframeiscomposedoftractionbeams,sleeperbeams,endbeams,sidebeamsandfloorsupportbeams,etc.Ofcourse,italsoincludessomestructuresforinstallingbogies,couplers,buffers,andunder-floorequipment.3BodystructureofKCIC400AFEMUThesidewallsarethepartsthatconnecttheroofandthebottomframe,andformthetwosidesofthecarbody.Thesidewallisfortheinstallationofsideslidingdoors,sidewindows,arrivaldisplays,seatnumberdisplays,interiorlightsandotherequipment.Thereareconsiderableopenings,butthevehiclebodymusthavesufficientstrength.Theouterpanelsofthesidewallsshouldbeprocessedassmoothlyaspossible.Theinnersurfaceofthesideplateislinedwithacertainthicknessofsoundinsulationandheatinsulationmaterial.Theendwallofthefrontheadincludesthesidewallandtheroofofthedriver'scab.Inordertoinstallthedriver's