附錄附錄AModifiedCarLiftingPlatformBasedonCATIAModelingandApplicationofDigitalPrototypingDescribestheuseofCATIAV5mechanicalpartsiandzero-dimensionalmodeling,virtualassemblyofthebasicprocesscomponentsandsteps,andwormassembly,forexampleindetail.Theeffectofimprovingthemechanicaldesigntoimprovedesignefficiencyandshortenthedesigncycletime,hassomepracticalsignificance1OverviewCATIAsoftwarefromIBMandDassaultcompanytolaunchhigh-endCAD/CAMsoftware,hasbecometheinternationalaviationindustrypreferreddesignsoftware.Withitsstrongsurfacedesignfeaturesinthemachinery,aircraft,automobile,shipbuildingandotherwidelyuseddesign,CATIAsurfacemodelingcapabilitiesisreflectedinthefeaturesandadvantagesitprovidesaveryrichmodelingtoolstosupporttheusermodelingneeds.Asitsuniquehigh-orderBeziercurveandsurfacefeatures,thenumbercanreach15,canwellmeetspecificindustrydemandingrequirementsofsurfacesmoothness.ApplicationCATlAconstructedsolidmodelcanbedirectlyappliedtootheranalysissoftwareANSYSfiniteelementanalysisCATIAsoftwarewiththree-dimensionalCADsoftwareandotherstandarddatainterfaceforeasydataconversionmodel.CATIAV5isbasedontheWindowsplatform,andtofullyparametricfeaturemodelingtechnologyasthecorefeature-basedmodelingsoftware,whichisconsistentwiththeWindows-stylemenubar,standardshortcuts,contextualmenus,multi-documentinterface,youcanmakethedifferenceWindowsapplicationstosharedata,OLEintegration,soworkquicklyandefficiently,cansignificantlyreducetrainingtime.CATIApartsassemblyisbasic,butalsothemostadvantagesandfeaturesfunctionmodules,includingthecreationofanassembly,addthespecifiedcomponentsorpartstotheassembly,theassemblyrelationshipbetweencomponentstocreate,moveandlayoutoftheassemblymembers,generatedanexplosionofproductsdiagram,assemblyinterferenceandgapanalysisandothermajorfeatures?.2three-dimensionalmodelingbasedonCATIAandassembly2.1DesignsketchesSketchdesignisthestartingpointofthree-dimensionaldesign,anditsessenceisatwo-dimensionalline,surfacedesign,softwaredesignwithatraditionaltwo-dimensionalfunctions.Parametricdesignofthebasicapproachistostartfromscratchdesign,sizeandgeometricconstraintsimposedbycreatingasketchfeature,thenapplythesize-driventechnologytoautomaticallygeneratepartsofthethree-dimensionalsolidmodel,intheuseoftechnologytogeneratetwo-dimensionalcontoursketchesdonothavetooutlinetheexactsizeoftheinput,theparametersinthefuturetogetthedesignprocess.Thus,duringtheproductdesign,youcanalwaysadjustthedesignsize,withoutaclearearlyinthedesignofthedesignsize,enhancetheeaseofCADsoftware,tobetterachieveauser-friendlydesign,butalsoforthedesignofseriesimprovementofproductsandoriginalproductsandparts"borrowed"areconvenient.2.2togeneratethree-dimensionalpartblankCATIAhasastrongthree-dimensionalsolidmodelingfunctionality,theuserplaneinthesketch,afterdrawingtwo-dimensionalgraphics,intothepartdesign(PartDesign)modules,youcanrotate,stretch,lofting,stiffened,andothermethodstogeneratethedraftthree-dimensionalpartstoberough.Constraintscanalsouseparameterizedfunctionstobemodifiedaccordingtoneed.Designerscanchangeforthebodypartblanktoachievethedesignprocessby"drawing"to"design"changes,andCATIAV5providesthree-dimensionalmodelofthespecificfeaturesmakethedesignmoresimilartotheproductionprocess,bettertoachieveacombinationofdesignandprocessing.2.3completethethree-dimensionalmodelingCATIAV5providesfeature-baseddesign,willfeatureasadesignelement,thecharacteristicsoftheproductasacombination,throughtheobjectfromtheclasstobeachievedstepbystepdescriptionofthespecificshapeofthedesign.Aftergeneratingtheroughthree-dimensionalpartscanbeusedtodrilling,slotting,shells,chamfer,plusconvexsets,suchasTwithinternalandexternalthreadsonthe"rough"to"processing",thefinalcompletionofmechanicalpartssolidmodeling.2.4completethevirtualassemblyVirtualassemblyisusingvirtualassemblytechnology,three-dimensionalcomputermodelwillbeassembledtogether,itcanavoidtheapplicationofphysicalprototypes,butalsoforpartsforclearanceandinterferencetesting,reducethesampleerrorrate.Intheproductdesignprocesscanusevarioustechniquessuchasanalysis,evaluation,simulation,andgivefullconsiderationtotheassemblyareasandrelatedproductsduringthevariouspossiblefactors.Productperformanceandfunctionalitytomeettheconditionstoimprovetheproductassemblystructure,thedesignoftheproductnotonlyassembly,andminimizeassemblycostandtotalproductcosts,shortendesigncycles.CATIA-basedvirtualassemblymodelhasparallel,bottom-upandtop-downapproachtoproductdevelopment,thisarticlefocusesonbottom-updesign.Constructthefirstmoduleinthepartsofpartsofthethree-dimensionalmodel,thencomponentsintheassemblymoduletocreateconstraintsbetweentheposition,orientationrelationships,abouttherelationshipbetweenpartstoquantifytheactualwiththevirtualassemblyprocessbetweenthevariouscomponentsentitieslocationconstraintrelationship.Inthisway,partsofthegeometryisbeingusedintheassemblyprocess,andnotsimplybecopiedtotheassembly,totrulyrealizethepartofthe"virtual"assembly.CATIAassemblyworkbenchprovidesaflexibleandintuitivetooltodeterminetherelationshipbetweenparts.Workbenchallowsuserstoassemblethecomponentpartsandvarioussub-assembliescombinedtogethertoformthefinalassemblyintheassemblyenvironment,accordingtothedefinedconstraints,partscanbemodified,analysis,andrelocationHJ.CATIAfeatureswithasingledatabase,regardlessofhoweditorseditpartsandcomponentswherethewholeassemblyofpartstomaintaintheconsistencyofassociation,ifyoumodifythecomponents,assembliesthatreferenceitautomaticallyupdated,real-timecomponentsreflectthelatestchange.Virtualassemblysteps:theassemblyprovidedinCArllAbench,leadersneedtoassemblethepartsandcomponents(CATIAprovidesthemainmethodofinsertingpartsintoparts,intotheproducts,partsandinsertnewcomponentsintoexisting,etc.).Then,theconstraintsonthecomponentsandtheestablishmentofappropriateassemblyrelationship,accordingtotherequirementsofthedifferentpartsoftheassembly,useadifferentconstraintrelations,andfinallygetacompleteassemblymodel.AndPro/EcomparedtotheassemblyprocessusingCATIAhasautomaticallycreatedtwopartstobeassembledtheirdesignbasispointsofoverlapbetweencomponentstofacilitatethedesigneracleardesignbasisbetweentheassemblyandpartsbetweenthebasedifference.3DesignExampleThewormdrive,forexample,theuseofCATIAmodelingandassemblyprocessandmethodsdescribed.3.1tocreatethree-dimensionalmodelwormAnalysisofthestructureofthewormpart,clearlythemainfeaturesofthestructuretodeterminethemodelingsteps.Byrotatingthewormbody,composedofthealveolarandkeywayparts,thebasiccharacteristicsofarotatingbody.3.1.1Createthree-dimensionalmodelofthewormpart(1)indraftmodetodrawshapesaccordingtotheroughshapeofthewormroughsketches,theestablishmentofsizeconstraints,suchassizechanges,chamfer,etc.(ofcourse,alsointheformationofroughchamferaftertheentity).(2)Inthedesignmode,theuseofrotatingparts(Shaft)tooltogeneratewormblank.(3)Accordingtotheworm'sparameters,tocalculatethealveolarpitchwormandthewormscrewaccordingtothemodeofcurvesandsurfacesgeneratedawormwrappedaroundthespiral,astheslotscanningwire.(4)SincetheendofcylindricalwormArchimedesArchimedesspiral,obliqueaxialplanetoastraightline∞],sothewormshaftcanchoosealmostplane,indraftmode,drawatrapezoid(mustbeaclosedcurve),itsdistancefromtheaxisofthebottommarginisjustthewormtoothrootradius,bothsidesoftheedgeandfaceangleof20.(Note:Thepitchatbothsidesoftheedgedistanceshouldbethepitchcirclespacewidth).(5)inthepartdesignmodeusingthenarrowslot(Slot)tooltogenerateanalveolar;usethewholearrayoftoolstowormoutofthealveolarprocess.(6)indraftmodetodrawshapeskeyway,theuseofstretchcutting(Pocket)tooltogeneratekeyslot,tocompletethethree-dimensionalconstructionofthewormMode.3.1.2createthree-dimensionalmodelwormpartsAnalysisofwormpartsofthestructure,clearlyamajorcomponentcharacteristicstodeterminethemodelingsteps.Asthewormgearandringgearteethbythecore2parts,sotheringgearandthetoothshouldbeseparatedfromthecoremodel,andthenassembled.PartsusingCATIAmodelingplatformprovidedbytheringgearandthewormweregeneratedtoothcore.3.2partsoftheassembly3.2.1ImportPartsAssemblyinCATIAprovidestheproductstructureworkbenchtoolbar,useofexistingpartsintothefunctionofthepriorconductivityhasbeendesignedwormandwormparts.3.2.2theestablishmentofbindingAspartoftheimportprocessCAITAhasestablishedaworminthewormandtheaxialprofilewidthof1/2ofthefaceoverlapconstraintrelations,haspledgeditsprofileinthewormdriveofthemain(centersection)onthealignment,inTheonlyothertwotodeterminethedirectionoftheconstraintrelationship.Centerdistancewormgearinaccordancewithrequirements(centerdistancewormandwormgearduringphysicalmodeling,basedonthegeometricparametersofwormandwormcalculated),theestablishmentofthewormandwormwheelaxisoffsetbetweentheaxisofrestrainttoensurethatthedifferencebetweenthedistancetomeetthedesignrequirements.Alongtheaxisofthewormtoestablishwormconstraintrelation,whichistoensure"inthemiddleofthewormandwormgearwormsideoftheaxisofsymmetryperpendiculartotheplane"and"wormwidth1/2symmetryonthealveolarsurfaceprofile"coincidence(Note:duringthewormandwormwheelsolidmodelingcalculationsmustbeaccurate,otherwiseitwillnotbeaccuratewormandwormwheelworkingposition)toensurethatthewormandwormgearinstalledinthecorrespondingposition.GeneratedasshowninFigure1wormdriveassemblymodel.4ConclusionCATIA3Ddesignsoftwaredesigntoolsprovideacompleteandconvenientuserinterface,theinterfaceandoptionsdesignedwithaconsistentstylewithMicrosoftproducts,greatlyreducingtheuserforthesoftwaretolearnandadapttothecycle,toalargeextentimprovedtheoperationofcomplex3Dmodelingsoftwaredefects.Meanwhile,CATIAfeature-based3Dmodelingfunctionsithasthefollowingadvantages:(1)inheritedtheuseofsolidmodelingsoftwareforproductdesign,theusercandirectlyseeonthescreenthetruethree-dimensionalmodeloftheproductcharacteristics,tomodeltheirideasclosertothebodycomposition,moreintuitivedesign.(2)parametricdesignchangestofacilitatethegraphicsize,quicklyplotted,relativetothetwo-dimensionalgraphicsmethods,designedtogreatlyreducetheworkload,especiallyinthesubsequentparametricdesignforthetechnicalstaffprovidesaneasydesign,easytomodifytheplatform,facilitatingproductserialdesign.(3)Thefeature-basedmodelingidea,theuseofBooleanoperatorsseekingintersectinglines,intersectinglines,theengineeringdrawingspeedfaster,moreaccurateline.(4)assemblymethodusingavirtualmachine,youcandirectlychecktheproductdesignspacemechanicalsystemcomponentsandassemblyofinterferenceandtofurthervisualizethedesignandanalysis,concurrentengineeringhasacertainsignificance.

附錄B基于CATIA的汽車改裝式升降臺數字樣機建模及應用研究介紹了利用CATIAV5進行機械零件i維造型以及零、部件虛擬裝配的基本過程與步驟，并以蝸輪蝸桿裝配為例進行詳細說明。對于改善機械設計的效果、提升設計效率、縮短設計加工周期，具有一定的現實意義1概述

CATIA軟件是IBM公司和Dassault公司合作推出的高端CAD／CAM軟件，現已成為國際航空工業首選的設計軟件。它以其強大的曲面設計功能在機械、飛機、汽車、造船等設計領域得到廣泛應用，CATIA的曲面造型功能的特點和優勢體現在它提供了極豐富的造型工具來支持用戶的造型需求。如其特有的高次Bezier曲線曲面功能，次數能達到15，能很好地滿足特殊行業對曲面光滑性的苛刻要求。應用CATlA構造的實體模型可直接應用于ANSYS等分析軟件中進行有限元分析。CATIA軟件具有與其他三維CAD軟件標準的數據接口，方便模型數據的轉換。

CATIAV5是基于Windows平臺的全參數化和以特征建模技術為核心的特征造型軟件，它與Windows保持一致風格的菜單條、標準的快捷鍵、上下關聯的菜單、多文檔界面、可以使不同的Windows應用程序共享數據的OLE集成，使工作快速高效，可顯著減少培訓時間。零件裝配是CATIA基本的、也是最具優勢和特色的功能模塊，包括創建裝配體、添加指定的部件或零件到裝配體、創建部件之間的裝配關系、移動和布置裝配成員、生成產品的爆炸圖、裝配干涉和間隙分析等主要功能?。

2基于CATIA的三維造型與裝配

2．1草圖設計

草圖設計是三維設計的起點，其實質是二維線、面設計，具有傳統二維軟件設計的功能。參數化設計的基本方法是從草圖設計開始，通過施加尺寸和幾何約束生成草圖特征，再應用尺寸驅動技術自動生成零件的三維實體模型，在利用草圖技術生成二維輪廓時不必輸入輪廓的準確尺寸，可以在以后的參數設計過程中得到。這樣，在進行產品設計時，可以隨時根據需要調整設計尺寸，而不必在設計之初就明確各設計尺寸，增強了CAD軟件的易操作性，更好地實現了人性化設計，而且對于設計系列產品及原產品的改進和零部件的"借用"都方便。

2．2生成三維零件毛坯

CATIA具有很強的三維實體建模的功能，當用戶在草圖平面繪制二維圖形后，進入零件設計(PartDesign)模塊，可以通過旋轉、拉伸、放樣、加肋、拔模等方法生成所需的三維零件毛坯。同時還可利用參數化約束功能，根據需要隨時進行修改。設計者可以直接針對零件毛坯進行形體改變，實現了設計過程由"繪圖"向"設計"的轉變，而且CATIAV5提供的各項具體功能使三維模型的設計更類似于生產加工過程，較好地實現設計與加工的結合。

2．3完成三維造型

CATIAV5提供基于特征的設計，即將特征作為設計的單元，將產品視為特征的有機結合，通過由類到對象的逐步描述來實現具體的形狀設計。在生成三維零件毛坯后，可利用打孔、開槽、抽殼、倒角、加凸臺、內外螺紋等T具對"毛坯"進行"加工"，最終完成機械零件實體造型。

2．4完成虛擬裝配

虛擬裝配是利用虛擬裝配技術，在計算機上將三維模型裝配到一起，這樣可避免物理原型的應用，也可對零部件進行間隙和干涉檢驗，減少樣品差錯率。能在產品設計過程中利用各種技術手段如分析、評價、仿真等，并充分考慮產品的裝配環節及其相關過程中各種可能因素的影響。在滿足產品性能與功能的條件下改進產品的裝配結構，使設計出的產品不但可以裝配，并盡可能降低裝配成本和產品總成本，大大縮短設計周期。

基于CATIA的虛擬裝配模式有并行、自下而上和自上而下的產品開發方法，本文重點介紹自下而上的設計方法。先在零件模塊中構造各零件的三維模型，然后在裝配模塊中建立零部件之間的位置約束、定位關系，即將零件間的實際配合關系量化為虛擬裝配過程中的各零部件實體之間的位置約束關系。這樣，零部件的幾何體是在裝配過程中被利用，而并不是簡單地被復制到裝配中，真正地實現了零件的"虛擬"裝配。

CATIA的裝配工作臺提供靈活、直觀的工具，用來確定各零件間的關系。裝配工作臺允許用戶將各個組成零件和各種子裝配件組合到一起形成最終的裝配體，在裝配環境中，根據定義的約束，零件可以被修改、分析以及重定位HJ。CATIA具有單一數據庫的特性，不管如何編輯零部件和在何處編輯零部件，整個裝配部件保持關聯的一致性，如果修改整個零部件，則引用它的裝配件自動更新，實時反映零部件的最新變化。虛擬裝配的步驟：在CArllA所提供的裝配工作臺上，導人需裝配的零、部件(CATIA提供的插入部件的方法主要有插入部件、插入產品、插入新部件和插入已存在的部件等)。然后，對零部件進行適當的約束并建立裝配關系，根據不同零件的裝配要求，選用不同的約束關系，最后得到完整裝配模型。

與Pro／E相比，使用CATIA進行裝配的過程中已經自動建立了2個待裝配零件各自的設計基準點的重合關系，便于設計者