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毕业设计中英文翻译IntroductiontoMechanicalDesign机械设计简介学生姓名：学号：0学院：机械工程与自动化学院专业：机械设计制造及其自动化指导教师：2011年06月高洪宇0702014425机械工程与自动化学院IntroductiontoMechanicalDesignTheDesignProcessAmachineisacombinationofmechanismandothercomponentswhichtransforms,transmits,orutilizesenergy,force,ormotionforausefulpurpose.Examplesareengines,turbines,vehicle,hoists,printingpresses,washingmachines,andmoviecameras.Manyoftheprincipleandmethodsofdesignthatapplytomachinesalsoapplytomanufacturedarticlesthatarenottruemachines,fromhubcapsandfilingcabinetstoinstrumentsandnuclearpressurevessels.Theterm“mechanicaldesign”isusedinabroadersensethan“mechanicaldesign”toincludetheirdesign.Forsomeapparatus,thethermalandfluidaspectsthatdeterminetherequirementsofheat,flowpath,andvolumeareseparatelyconsidered.However,themotionandstructuralaspectsandtheprovisionsforretentionandenclosureareconsiderationsinmechanicaldesign.Applicationsoccurinthefieldofmechanicalengineering,andinotherengineeringfieldsaswell,allofwhichrequiremechanicaldevices,suchasswitches,cams,valves,vessels,andmixers.Designingstartswithaneed,realorimagined.Existingapparatusmayneedimprovementsindurability,efficiency,weight,speed,orcost.Newapparatusmaybeneededtoperformafunctionpreviouslydonebymen,suchascomputation,assembly,orservicing.Withtheobjectivewhollyorpartlydefined,thenextstepindesignistheconceptionofmechanismsandtheirarrangementsthatwillperformtheneededfunctions.Forthis,freehandsketchingisofgreatvalve,notonlyasrecordofone’sthoughtsandasanaidindiscussionwithothers,butparticularlyforcommunicationwithone’sownmind,asastimulantforcreativeideas.Also,abroadknowledgeofcomponentsisdesirable,becauseanewmachineusuallyconsistsofanewarrangementorsubstitutionofwell-knowntypesofcomponents,perhapswithchangesinsizeandmaterial.Eitherduringorfollowingthisconceptualprocess,onewillmakequickorroughcalculationsoranalysestodeterminegeneralsizeandfeasibility.Whensomeideaastotheamountofspacethatisneededoravailablehasbeenobtained,to-scalelayoutdrawingmaybestarted.Whenthegeneralshapeandafewdimensionsoftheseveralcomponentsbecomeapparent,analysiscanbegininearnest.Theanalysiswillhaveasitsobjectivesatisfactoryorsuperiorperformance,plussafetyanddurabilitywithminimumweight,andacompetitivecost.Optimumproportionsanddimensionswillbesoughtforeachcriticallyloadedsection,togetherwithabalancebetweenthestrengthsoftheseveralcomponents.Materialsandtheirtreatmentwillbechosen.Theseimportantobjectivescanbeattainedonlybyanalysisbasedupontheprinciplesofmechanics,suchasthoseofstatic’sforreactionsforcesandfortheoptimumutilizationoffriction;ofdynamicsforinertia,acceleration,andenergy;ofelasticityandstrengthofmaterialsforstressanddeflection;ofphysicalbehaviorofmaterials;andoffluidmechanicsforlubricationandhydrodynamicdrives.Theanalysesmaybemadebythesameengineerwhoconceivedthearrangementofmechanisms,or,inalargecompany,theymaybemadebyaseparateanalysisdivisionorresearchgroup.Asaresultoftheanalyses,newarrangementsandnewdimensionsmayberequired.Designisreiterativeandcooperativeprocess,whetherdoneformallyorinformally,andtheanalystcancontributetophasesotherthanhisown.Finally,adesignbaseduponfunctionandreliabilitywillbecompleted,andaprototypemaybebuilt.Ifitstestsaresatisfactory,andifthedeviceistobeproducedinquantity,theinitialdesignwillundergocertainmodificationsthatenableittobemanufacturedinquantityatalowercost.Duringsubsequentyearsofmanufactureandservice,thedesignislikelytoundergochangesasnewideasareconceivedorasfurtheranalysesbasedupontestsandexperienceindicatealterations.Salesappeal,customersatisfaction,andmanufacturingcostareallrelatedtodesign,andabilityindesignisintimatelyinvolvedinthesuccessofanengineeringventure.SomerulefordesignInthesectionitissuggestedthat,appliedwithacreativeattitude,analysescanleadtoimportantimprovementsandtotheconceptionandperfectionofalternate,perhapsmorefunctional,economical,anddurableproducts.Thecreativephaseneednotbeaninitialandseparateone.Althoughhemaynotberesponsibleforthewholedesign,ananalystcancontributemorethanthenumericallycorrectanswertoaproblemthatheisaskedtosolve-morethanthevaluesofstress,dimensions,orlimitationsofoperation.Hecantakethebroaderviewthatthespecificationsorthearrangementsmaybeimproved.Sincehewillbecomefamiliarwithdeviceanditsconditionsofoperationbeforeorduringhidanalysis,heisinagoodpositiontoconceiveofalternatives.Itisbetterthathesuggestachangeinshapethatwilleliminateamomentorastressconcentrationthantoallowconstructionofamechanismwithheavysectionsandexcessivedynamicloads.Itisbetterthathescraphisfineanalysis,ratherthanthathelaterseethemechanismscrapped.Tostimulatecreativethought,thefollowingrulesaresuggestedforthedesignerandanalyst.Thefirstsixrulesareparticularlyapplicablefortheanalyst,althoughhemaybecomeinvolvedwithalltenrules.1.Applyingenuitytoutilizedesiredphysicalpropertiesandtocontrolundesiredones.2.Recognizefunctionalloadsandtheirsignificance.3.Anticipateunintentionalloads.4.Devisemorefavorableloadingconditions.5.Provideforfavorablestressdistributionandstiffnesswithminimumweight.6.Usebasicequa