会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

外文翻译--超轻车辆设计 采用先进的汽车合成技术克服设计阻碍英文版.pdf外文翻译--超轻车辆设计 采用先进的汽车合成技术克服设计阻碍英文版.pdf -- 5 元

宽屏显示 收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

ULTRALIGHTHYBRIDVEHICLEDESIGNOVERCOMINGTHEBARRIERSTOUSINGADVANCEDCOMPOSITESINTHEAUTOMOTIVEINDUSTRY1.INTRODUCTIONAdvancedpolymericcompositeshaveseveraladvantagesincludingpartsconsolidation,highspecificstrengthandenergyabsorption,stylingflexibility,goodnoise/vibration/harshnessNVHcharacteristics,andexcellentcorrosionresistancethatsuitthemtoautomobiles.Furthermore,technologicaladvancesinprocessingandmaterialsappeartomakeadvancedcompositessuitableforhighvolumeapplicationslowpressurefabricationprocessessuchasresintransfermoldingRTMcouldrequireverylowinvestmentcostsand,dependingonthechoiceofresinandtoolingmaterial,offerfastcycletimes,whilenewversionsofresinsandfiberspromiselowcostandhighperformance.Inaddition,recentdevelopmentsinautomotivedesigndrivetheneedforwhatispotentiallyadvancedcompositesbiggestadvantagemassreduction.Ultralighthybridvehicledesigns,suchasRockyMountainInstituteshypercarconcept,necessitatestringentmassoptimizationparticularlyforthebodyinwhite1,theautomotivetermfortheunfinishedbodyanditsframeorchassis.Advancedcompositebodiesinwhitehavethepotentialtobeupto67lighterthanaconventionalsteelunibodyforequivalentsizeandsafety.However,aquicklookattheuseofadvancedcompositesintheautomotiveindustryraisesanobviousquestionIfadvancedcompositesaresuchwonderfulmaterials,whyaretheynotbeingusedAsidefromafewspecialtycomponentsfornichevehicles,suchasonepartintheDodgeViper,andevenfewerwholesystemapplicationssuchGMs1991Ultraliteconceptcar,theautoindustryhasshunnedtheuseofadvancedcomposites.Evenregularstructuralcomposites,usinglowperformancereinforcementsinquasiisotropicarrangements,arebeingappliedinlowerthanexpectedquantities.Inresponse,organizationstargetingtheautomotiveindustry,suchastheAutomotiveCompositesConsortiumACC,andcompositeproducers,includingsomeinNISTsAdvancedTechnologyProgramATP,areambitiouslyimplementingstrategiestospeedtheintegrationofstructuralandadvancedcompositesintotheautomobile.ButtheACCsfocusoncomponentapplicationssuchasacompositepickuptruckbox,liketheATPsfundingofmanufacturingprocessimprovementswithoutaccompanyingdesignchanges,indicateastrategyofevolutionaryintegration.Whileanevolutionaryapproachminimizesriskintheshortterm,itmaynotbetheoptimallongtermstrategytoovercomethebarrierstoputtingadvancedcompositesintocars.Justasthecombinationofanultralightbodywithahybriddrivelineprovidesaleapfrogapproachtoincreasingfuelefficiencyanddecreasingemissions,sothewholesystemapplicationofcompositestoanultralightmonocoqueBIWisthebestwayfortheadvancedmaterialsandautomotiveindustriestotunnelthroughthebarrierstolargescaleimplementation.Toanautomaker,aleapfrogapproachtocompositeintegrationcouldprovidebenefitsfaroutweighingtherisksanduncertaintiesofworkingwithunfamiliarmaterialsandtechnologies.Toanadvancedmaterialssupplier,aleapfrogapproachcanpreventthesetuptofailscenarioexperiencedinmanyautomotivecomponentapplicationsbyoptimallyexploitingthenewmaterialsintrinsicadvantages.Inaddition,aleapfrogapproachcouldpotentiallyexpandtheadvancedmaterialsmarketbyseveralfoldormore,achievingvolumeswhichcouldlowertheirproductscosts.ThusanadvancedmaterialspushintotheBIWshouldnotbesimplyanissueofmaterialsubstitutiononepartatatimeitneedstosubstitutematerialsusingawholeplatformdesignthatmaximizesthematerialsbenefitswhileminimizingandpotentially1eliminatingmanyoftheircosts.2.TECHNOLOGIESFORVOLUMEPRODUCTIONHowcouldpolymericcompositeBIWsbecompetitivelymadeinhighvolumeThereisnodefinitiveanswertheslateofpotentialtechnologiesforfabricatingandassemblinganadvancedmaterialsbasedBIWislargeandgrowingrapidly.Thediversityoftechnologicaloptionsaddsbothuncertaintyandrobustness.Also,whileadvancedpolymericcompositesrequiresophisticateddesigntotakeadvantageofuniquepropertiessuchasanisotropy,theirhighvolumemanufacturingandassemblytechniquesareconceptuallysimple.ThemostpromisingofftheshelforneartermtechnologiesforBIWmanufacturingarebrieflylistednextafullersurveyisin.2.1RawMaterialsPolymericcompositesincorporatefibrousreinforcementinaresinmatrix.Issuesimportantforrawmaterialselectionincludecost,compatibilitywithfabricationtechnologies,mechanicalandenvironmentalperformance,andrecyclability.2.2MoldingInthevariousmoldingoperations,theintermediatefiberformandresin,combinedeitherpreviouslyordirectlyinthemold,areshapedandhardenedintotheformofthemoldingcavity.ForanallcompositeBIW,liquidcompositemoldingLCMeitherresintransfermoldingRTMorstructuralreactioninjectionmoldingSRIMisgenerallyconsideredtobethemostpromisingprocess.BothRTMandSRIMutilizethermosetresinsbecauseoftheirlowviscosity,althoughcyclicthermoplasticsmaybeadaptable.LCMrequiresapreform,whichcancompriseavarietyofintermediatefiberforms.Asmentionedabove,anadvancedcompositeBIWwouldprobablyuseamorecomplexpreformwithhigherperformancefibers.Compressionmolding,normallydonewithSheetMoldingCompoundSMC,isahighpressureprocesswithalowercycletimeandgenerallyabettersurfacefinishthanLCM,suitingittoBIWapplicationswithinthecurrentsteelinfrastructure.However,likeglass,afullycompressionmoldedBIW,duetoitsweight,maynotbeabletoreapadequatesynergieswithahybriddrive,norhaveadequatecrashworthiness.BIWdesigns,lessmaturebuthigherperformancemanufacturingtechnologiessuchasRTMorSRIMappeartobemoreapplicabletoanallcompositeBIW.2.3TechnologicalBarriersUnliketheoveralldesignstrategyforcompositeBIWs,noneofthecompositetechnologieslistedaboverequirefundamentaladvancestopermitvolumeBIWmanufacturing.Eachneedsvaryingdegreesofrefinementbutseemstofacenointractabletechnologicalbarriersimplementationrequirestechnologyoptimizationandintegrationratherthaninvention.Someofthekeytechnoeconomicbarriersaredescribednext.2.3.1CarbonFiberCostThecostofcarbonfiberisoftencitedasthemostformidablebarriertocommercialapplicationsforcarbonfibercomposites.ForPANbasedcarbonfiber,thecombinationofexpensiveprecursorandlowvolume,specializedequipmenthasledtoitshighcost.However,twoenterprisingdomesticmanufacturers,ZoltekandAkzoNobel,offerlowcost,hightowcommoditygradecarbonfiber.Bulkcreelpricesfortheircontinuousfiberarecurrentlyaslowas17.60/kg.Centraltofurtherdecreasesinpricearecheaperversionsoftheprecursor,whichhasnocostcontrollingdifferencesfromthecommoditygradeacrylicfiberthatcosts3.00/kg.toproduce.Inaddition,highervolumesofproductionareneededtolowerunitcapitalandlaborcosts.HighvolumemanufacturingcouldsoonberealizedZoltekandAkzoplanneartermexpansion.Theirstrategycouldovercomethecostbarrierforadvanced2compositeswithasupplypushoflowcostfiberintothetransportationmarket.2.3.2PreformingThedifficultyofproducingcomplexpreformsatreasonablecostiscitedalmostasoftenascarbonfibercostasthechieftechnicalbarriertohighvolumeadvancedcompositesmanufacturing.PrincetonsConferenceonBasicResearchNeedsforVehiclesoftheFuturerecentlygavepreformingthehighestpriorityamongneededresearchandinnovation.Currently,automakersfavorquasiisotropicchoppedorcontinuousmatpreformsofglassfiber,which,aswasmentionedabove,aretooweak,isotropic,andhenceheavyforamassoptimizedBIW.Theanisotropicstrategiescommoninaerospaceapplications,suchasprepregtapesandhandlayupwithautoclaving,aretooslowandcostlyforcars.Fortunately,theproblemofcreatinglowcostcomplexpreformsmaynotbeintractableseveralinnovativetechnologiescouldpermittherapidandinexpensivefabricationofcomplex,netshapepreforms.FabricssuchasCOTECHarenoncrimp,stitchbondedlayersofunidirectionalcontinuousfiberthat,accordingtotheirmanufacturer,canbecheaperthanrandommatyetperformaboutaswellasunidirectionaltape.Astitchbondingprocesscaninexpensivelycreatecomplexpreformsbycombiningaquasiisotropicbaseoffabricwithstrategicallyplacedinsertsofunidirectionalfabricorrovingatmaximumloadpoints.Alternatively,theCompFormprocessclaimsevencheaperandfastercomplexpreformingpotential,substitutingUVcurablebindersforfabricstitchesalthoughthisprocesscannotbeusedwithacarbonintensivepreform.Forcreatingnetshapepreforms,fastultrasoniccutting,usingnestingpatternstominimizewaste,couldbeagoodcomplementtostitchbonding.Obviously,complexpreformsrequireheavyfrontendengineeringtoavoidresinflowproblemssuchasracetrackingandunexpectedfibermovements.Nevertheless,theseprocesseshaverealworldvaliditybothUVstitchingandultrasoniccuttingwereusedtocreateacomplexpreformforaBuickRivierabumperbeam.2.3.4SurfaceQualityBecausecompositemonocoquesrequirestructuralcompositeswithClassAsurfaces,asignificantbarrierisproducingcomponentswithbothhighfibervolumefractionsandsmooth,porosityfreeexteriors.IfsofttoolingisusedtocapturestrategicadvantagesortoensurecompatibilitywithEbeamcuringforcycletimereductions,thechallengeofobtainingClassAsurfacesbecomesmorecomplexandimportant.WhileClassAsurfacescouldbedifficultforstructuralcomposites,theyarebynomeansimpossible.Thestitchbondedfabricdescribedaboveforcomplexpreformswetsouteasilyandhasasurprisinglysmoothsurface,asitismadeupofunidirectionallayers,sosubjecttoresinconsistencyandtoolingsurfacequality,itcouldsimplybesurfacefinishedwithaClassAmoldandpainted,savingtheinvestmentandoperationcostsofconventionalsteelfinishingprerequisitetopaintingexteriorBIWparts.AnevensimplerapproachcouldalsoavoidpaintingbyapplyingoneofseveralproprietarylayinthemoldClassAcolorcoatpolymerproducts,orperhapsinjectathermoplasticcolorcoatintoaClassAmoldandthenlayinthestructuralelementsbehinditusingacompatibleresinsystem.3.OVERCOMINGTHEBARRIERSTheresultsofthesesurveysledonesetofinterviewerstoconcludethatsincetheadoptionofstructuralcompositesfacesmultiplebarriers,noonesimplequickfixwillrapidlyacceleratetheirdeployment.Yetdespitecompleximplementationdetails,thereisarelativelysimpleifunexpectedconceptualframeworktointegrateadvancedcompositesintoautomaking.Themosteffectivewaytoovercomethebarriersappearstobereplacingtodaysdominantstrategyofincremental,partbypartmaterialssubstitutionwithawholesystemdesigned,alladvancedcompositeBIW.Thisleapfrogapproachintegratesacleansheetdesign,highperformancerawmaterials,3existingmanufacturingmethods,andaradicallysimplerandsmallerassemblyprocess.Itholdspromiseofbypassingmanybarriersandofchangingautomakersattitudetowardadvancedcompositesfromanecessaryevilorindefinitelypostponableinconvenienceintoapromptandlucrativeopportunity.Waystocircumventmajorbarriersaresurveyednext.3.1CostComponentbycomponentsubstitutionofcompositesforsteelcannotoccuruntilmarketdeterminedmaterialpricesjustifysubstitutiononasinglepartbasis,eitherthroughcheapermanufacturingorthroughsavedgasoline,withlittleifanycreditformassdecompoundingandevenforthesavedsteelitself.Thesubstitutedmaterialsremaincostly,however,becauseonlysmallvolumesarebeingbought.Creditshouldbe,butisnotalways,takenforthemodestreductionsinpartscountasaresult,thinkingincomponenttermsmakesithardorimpossibletoquantifysavedassemblycosts.Finally,integrationofacompositecomponentwithinasteelBIWcanraiseoverallassemblycosts,especiallyifthecompositepartscycletimesarelongerortheirdimensionsandotherpropertiesaremorevariable.Asaresult,integrationrequirementsofteneconomicallyfavorcompressionmoldingoverRTM,leadingtopartswithsuboptimalperformancefordemandingstructuralapplications.Incontrast,cleansheetwholeplatformredesigncanyieldradicalreductionsinpartscount,size,andcomplexitythetypicalBIWwouldhaveonlyafewparts,andassemblyeffortwoulddropbyanorderofmagnitude.Buyingthespecialmaterialsinbulkshouldyielddiscountsand,throughincreasingproductionvolumes,cutmarketprices.Productionvolumescouldbeoptimizedforconvenienceandmarketdemand,ratherthanartificiallyinflatedtomeetamortizationrequirementsforsteeltoolsandpresses.Productionflexibilitycouldberetainednotonlyinvolumebutalsoinstyling.Finally,savingscouldaccumulatedownstreamfromBIWmanufacturingthroughamuchsmallerandsimplerdrivelineandothercomponents,shorterproductcycletimes,andgreaterproductionflexibility.3.2SafetyAdvancedcompositeshavefundamentallydifferentenergyabsorptioncharacteristicsandfailuremodesthansteel.Theyfituncomfortablyintothetraditionalsafetydesignparadigm,especiallywhenappliedbysteelorienteddesignerswhotreatadvancedcompositesasblacksteel.Inadequateredesigncanyieldsuspectcompositeparts,creatinganimpressionofpoorsafety.However,cleansheetdesignofanallcompositeBIWcantakeadvantageofthesematerialsuniqueproperties,including,inpropershapes,specificenergyabsorptionfivetimesthatofsteel.Equivalentsafetyforanultralight,usingsuperiormaterialsanddesigntocompensateforlightmass,requiresanewdesignapproachimplementableonlyatthesystemlevel,notinisolatedcomponentsalone.ToexplicatethedesignparadigmforanallcompositeBIW,RMIiscurrentlypreparingaprimeronultralightcompositebasedcarsafetyprinciplesandpraxis.3.3RiskLesswidelyperceivedthantheriskofleapfroggingtoanallcompositeBIWistheinherentandoftenruinousriskofthepresentBIWmanufacturinginfrastructure.Itsinherentlyhighfixedcostsandlowvariablecostsmakeprofitsextremelysensitivetosalesvolumes,endangeringincomewheneverdemandfalters.Furthermore,thehighfixedcostsimpellargeproductionruns,whichshrinkmodelvarietyandfocusmoreriskonthemarketsuccessofeachmodel.Longproductcycles,too,makenewmodelslagbehinddynamicpublictastes,furtherheighteningtheriskofdisastrousventures.Conventionalcomponentbaseduseofcomposites,forcedintothesameparadigm,couldcarrysimilarrisks.Incontrast,softtooled,netshapeadvancedcompositemonocoquescouldofferstrategicadvantageswithapreciselyoppositeriskprofile.Thetoolingcouldbecheaplyfabricatedwithfewparts,
编号:201311171215506318    大小:41.72KB    格式:PDF    上传时间:2013-11-17
  【编辑】
5
关 键 词:
教育专区 外文翻译 精品文档 外文翻译
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

4.0
 
(2人评价)
浏览:22次
英文资料库上传于2013-11-17

官方联系方式

客服手机:13961746681   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

教育专区   外文翻译   精品文档   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5