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西北工业大学硕士学位论文学校代码10699分类号TG386密级学号036046079题目汽车覆盖件CAD模型重构及成形过程数值模拟作者陈宏远学科、专业材料加工工程指导教师刘东申请学位日期2006.3摘要I摘要加入WTO后，随着全球经济一体化的不断发展，我国汽车业面临严峻的挑战。当前昀紧迫的任务是，将先进的科学理论和方法，特别是数字化信息技术应用到我国汽车工业的研发工作中，在技术引进和消化吸收的基础上，建立具有自主知识产权和较强市场竞争力的企业核心技术和开发平台，迅速摆脱我国汽车业受制于国外企业和创新能力低下的局面。在上述背景下，论文工作的内容是对汽车覆盖件的典型零件——汽车后备箱内板的冲压成形模具的曲面逆向重构技术和冲压成形过程CAE仿真技术进行系统地研究，为缩短新型汽车研发周期、提高汽车覆盖件和汽车的整体质量提供技术上的支持。为了建立汽车覆盖件冲压成形过程有限元模型，对用ATOS激光扫描测量系统获取的覆盖件及冲压模具的曲面点云数据进行精简和去噪工作，然后应用CATIA软件的有关模块，根据覆盖件冲压成形的特点，分别用逆向和正向的方法构建CAD模型的不同曲面。根据覆盖件的冲压成形及所用材料的特点，有限元仿真分析时选用Balart三参数屈服模型和Belytschko-Tsay壳单元。采用DYNAFORM软件对所建立的覆盖件CAD模型进行有限元仿真。对模具圆角和平滑曲面采用不同尺寸的单元，坯料的网格大小参考昀小凹模圆角半径来确定。对所讨论的覆盖件的有限元仿真计算结果揭示了覆盖件成形过程中缺陷的形成过程，从而提出了预防这些缺陷的措施。有限元仿真结果表明，影响覆盖件冲压成形的主要因素是压边方式，拉延筋的尺寸和位置，以及坯料的形状和尺寸。通过覆盖件成形过程的仿真，优化了冲压工艺方案，使覆盖件冲压成形性获得很大提高。综上所述，本论文所提供的一些结果对车身覆盖件制造水平的提高具有指导意义。本文中将逆向工程技术与汽车覆盖件成形过程仿真技术结合，对于推动我国汽车制造业信息化进行，具有重要的理论意义和实用价值。关键词：汽车覆盖件，逆向工程，点云，曲面重建，数值模拟，壳单元西北工业大学硕士学位论文IVAbstractWithdevelopmentofglobaleconomicintegrityafterenteringWTO,theauto-industryofourcountryfacesseriouschallenge.Atpresentitisinurgentneedtointroduceadvancedscienceandtechnology,especiallythedigitalinformationtechnology,intoresearchanddevelopmentofauto-industryforestablishmentofkeytechnologywithindependentknowledgepropertyrighttobeliftedoutofdependenceofforeignenterprisesandraisetheinnovativeability.Basedontheabovefacts,presentpaperfocusedattentiononcomprehensivestudyofsurfacereversereconstructionandCAEforformingprocessofautomobilebackbootinnerpanelinordertoshortentheperiodofresearchanddevelopmentformoderncar,improvethequalityofbodycoverpanelandautomobileinwhole.Tocreatefiniteelement(FE)modelforcoverpanelformingprocess,thereducingandnoiseeliminatingprocesswereemployedinthepointcloudofcoverpanelanditsdiesacquiredbyATOSlaserscanmeasuringsystem.Then,accordingtocharacteristicsofcoverpanelformingprocess,CATIAmodulescreatedeachsurfaceoftheCADmodelthroughreverseandobversemethod.Barlat’s3-parameteryieldmodelandBelytschko-TsayshellelementwereusedforFEsimulationaccordingtocharacteristicsofcoverpanelformingprocessandmaterials.CommercialFEsoftwareDYNAFORMwasemployedforFEsimulationofCADmodel.Elementswithdifferentsizewereusedforthecornerandsmoothsurfaceofdies.Theelementsizefortheblankwasdeterminedinthelightofminimumdiesfillet.ThesimulationresultsobtainedbyusingDYNAFORMcanrevealdevelopmentcourseofthedefectsduringbodycoverpanelformingprocessandmethodtopreventthedefectsfromoccurrencewasproposedbasedonthesimulationresults.Thesimulationresultsindicatedthattheprimaryfactorsthatdominatethecoverpanelformingprocessarethebindmode,dimensionandlocationofbeads,shapeanddimensionoftheblank.TheoptimizedparametersforcoverpanelformingprocesswereobtainedthroughFEsimulation.Tosumup,theresultspresentedinthepaperarevaluableforpracticeofcoverpanelformingprocess.IncorporatingreverseengineeringmethodintoFEsimulationofautomobilecoverpanelformingprocessisconducivetoemployinformationtechnologyinauto-industryandhasimportantscientificandpracticalsignificance.Keyword:auto-bodycoverpanel,reverseengineering,pointclouds,surfacereconstruction,FEsimulation,shellelement目录III目录摘要...................................................................................................................................................2Abstract............................................................................................................................................1第1章绪论...............................................................................................................................11.1引言....................................................................................................................................11.2CAE技术概况.....................................................................................................................21.2.1CAE技术的起源与发展状况.................................................................................21.2.2CAE技术在汽车覆盖件成形中的应用.................................................................51.3逆向工程技术....................................................................................................................61.3.1逆向工程技术的概念............................................................................................61.3.2逆向工程技术的应用............................................................................................71.3.2逆向工程技术的实现............................................................................................81.4本文的选题意义及主要内容...........................................................................................91.4.1选题目的与意义....................................................................................................91.4.2研究内容..............................................................................................................11第2章逆向工程技术的理论基础.........................................................................................122.1数据获取技术.................................................................................................................122.1.1接触式测量.................