机械类外文翻译.docx

机械类外文翻译.docx

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机械类外文翻译

MechanicalDesign

Abstract:

Amachineisacombinationofmechanismsandothercomponentswhichtransforms,transmits.Examplesareengines,turbines,vehicles,hoists,printingpresses,washingmachines,andmoviecameras.Manyoftheprinciplesandmethodsofdesignthatapplytomachinesalsoapplytomanufacturedarticlesthatarenottruemachines.Theterm"mechanicaldesign"isusedinabroadersensethan"machinedesign"toincludetheirdesign.themotionandstructuralaspectsandtheprovisionsforretentionandenclosureareconsiderationsinmechanicaldesign.Applicationsoccurinthefieldofmechanicalengineering,andinotherengineeringfieldsaswell,allofwhichrequiremechanicaldevices,suchasswitches,cams,valves,vessels,andmixers.

Keywords:

MechanicalDesign；RulesforDesign；DesignProcess

TheDesignProcess

Designingstartswithaneedreal.Existingapparatusmayneedimprovementsindurability,efficiency,weight,speed,orcost.Newapparatusmaybeneededtoperformafunctionpreviouslydonebymen,suchascomputation,assembly,orservicing.Withtheobjectivewhollyorpartly.

Inthedesignpreliminarystage,shouldallowtodesignthepersonnelfullytodisplaythecreativity,noteachkindofrestraint.Evenifhashadmanyimpracticalideas,alsocaninthedesignearlytime,namelyinfrontoftheplanblueprintiscorrected.Onlythen,onlythendoesnotsendtostopsuptheinnovationthementality.Usually,mustproposeseveralsetsofdesignproposals,thenperformthecomparison.Hasthepossibilityverymuchintheplanwhichfinallydesignated,hasusedcertainnotinplansomeideaswhichaccepts.

Whenthegeneralshapeandafewdimensionsoftheseveralcomponentsbecomeapparent,analysiscanbegininearnest.Theanalysiswillhaveasitsobjectivesatisfactoryorsuperiorperformance,plussafetyanddurabilitywithminimumweight,andacompetitivecost.Optimumproportionsanddimensionswillbesoughtforeachcriticallyloadedsection,togetherwithabalancebetweenthestrengthsoftheseveralcomponents.Materialsandtheirtreatmentwillbechosen.Theseimportantobjectivescanbeattainedonlybyanalysisbasedupontheprinciplesofmechanics,suchasthoseofstaticforreactionforcesandfortheoptimumutilizationoffriction;ofdynamicsforinertia,acceleration,andenergy;ofelasticityandstrengthofmaterialsforstressanddeflection;ofphysicalbehaviorofmaterials;andoffluidmechanicsforlubricationandhydrodynamicdrives.Theanalysesmaybemadebythesameengineerwhoconceivedthearrangementofmechanisms,or,inalargecompany,theymaybemadebyaseparateanalysisdivisionorresearchgroup.Designisareiterativeandcooperativeprocess,whetherdoneformallyorinformally,andtheanalystcancontributetophasesotherthanhisown.Productdesignrequiresmuchresearchanddevelopment.ManyConceptsofanideamustbestudied,tried,andtheneitherusedordiscarded.Althoughthecontentofeachengineeringproblemisunique,thedesignersfollowthesimilarprocesstosolvetheproblems.

Productliabilitysuitsdesignersandforcedinmaterialselection,usingthebestprogram.Intheprocessofmaterial,themostcommonproblemsforfive（a）don'tunderstandornotuseaboutthelatestapplicationmaterialstothebestinformation,（b）failedtoforeseeandconsiderthereasonableusematerialmay（suchaspossible,designersshouldfurtherforecastandconsiderduetoimproperuseproducts.Inrecentyears,manyproductsliabilityinlitigation,theuseofproductsandhurttheplaintiffaccusedmanufacturer,andwonthedecision）,（c）ofthematerialsusedallorsomeofthedata,data,especiallywhentheuncertaintylong-termperformancedataisso,（d）qualitycontrolmethodisnotsuitableandunproven,（e）bysomecompletelyincompetentpersonschoosematerials.

Throughtotheabovefivequestionsanalysis,mayobtainthesequestionsisdoesnothavethesufficientreasonexistencetheconclusion.Mayforavoidthesequestionstothesequestionsresearchanalysestheappearanceindicatingthedirection.Althoughusesthebestchoiceofmaterialmethodnottobeabletoavoidhavingtheproductresponsibilitylawsuit,designsthepersonnelandtheindustrycarriesonthechoiceofmaterialaccordingtothesuitableprocedure,maygreatlyreducethelawsuitthequantity.

Mayseefromtheabovediscussion,thechoicematerialpeopleshouldtothematerialnature,thecharacteristicandtheprocessingmethodhavecomprehensiveandthebasicunderstanding.

Finally,adesignbaseduponfunction,andaprototypemaybebuilt.Ifitstestsaresatisfactory,theinitialdesignwillundergocertainmodificationsthatenableittobemanufacturedinquantityatalowercost.Duringsubsequentyearsofmanufactureandservice,thedesignislikelytoundergochangesasnewideasareconceivedorasfurtheranalysesbasedupontestsandexperienceindicatealterations.Salesappeal.

SomeRulesforDesign

Inthissectionitissuggestedthat,appliedwithacreativeattitude,analysescanleadtoimportantimprovementsandtotheconceptionandperfectionofalternate,perhapsmorefunctional,economical,

anddurableproducts.

Tostimulatecreativethought,thefollowingrulesaresuggestedforthedesignerandanalyst.Thefirstsixrulesareparticularlyapplicablefortheanalyst.

1.Acreativeuseofneedofphysicalpropertiesandcontrolprocess.

2.Recognizefunctionalloadsandtheirsignificance.

3.Anticipateunintentionalloads.

4.Devisemorefavorableloadingconditions.

5.Provideforfavorablestressdistributionandstiffnesswithminimumweight.

6.Usebasicequationstoproportionandoptimizedimensions.

7.Choosematerialsforacombinationofproperties.

8.Selectcarefully,stockandintegralcomponents.

9.Modifyafunctionaldesigntofitthemanufacturingprocessandreducecost.

10.Provideforaccuratelocationandnoninterferenceofpartsinassembly.

Machinerydesigncoversthefollowingcontents.

1.Providesanintroductiontothedesignprocess,problemformulation,safetyfactors.

2.Reviewsthematerialpropertiesandstaticanddynamicloadinganalysis,

Includingbeam,vibrationandimpactloading.

3.Reviewsthefundamentalsofstressanddefectionanalysis.

4.Introducesfatigue-failuretheorywiththeemphasisonstress-lifeapproachestohigh-cyclefatiguedesign,whichiscommonlyusedinthedesignofrotationmachinery.

5.Discussesthoroughlythephenomenaofwearmechanisms,surfacecontactstresses,andsurfacefatigue.

6.Investigatesshaftdesignusingthefatigue-analysistechniques.

7.Discussesfluid-filmandrolling-elementbearingtheoryandapplication

8.Givesathoroughintroductiontothekinematics,designandstressanalysisofspurgears,andasimpleintroductiontohelical,bevel,andwormgearing.

9.Discussesspringdesignincludingcompression,extensionandtorsionsprings.

10.Dealswithscrewsandfastenersincludingpowerscrewandpreloadfasteners.

11.Introducesthedesignandspecificationofdiskanddrumclutchesandbrakes.

MachineDesign

Thecompletedesignofamachineisacomplexprocess.Themachinedesignisacreativework.Projectengineernotonlymusthavethecreativityinthework,butalsomustinaspectandsoonmechanicaldrawing,kinematics,engineerigmaterial,materialsmechanicsandmachinemanufacturetechnologyhasthedeepelementaryknowledge.

Oneofthefirststepsinthedesignofanyproductistoselectthematerialfromwhicheachpartistobemade.Numerousmaterialsareavailabletotoday'sdesigners.Thefunctionoftheproduct,itsappearance,thecostofthematerial,andthecostoffabricationareimportantinmakingaselection.Acarefulevaluationofthepropertiesofa.materialmustbemadepriortoanycalculations.

Carefulcalculationsarenecessarytoensurethevalidityofadesign.Incaseofanypartfailures,itisdesirabletoknowwhatwasdoneinoriginallydesigningthedefectivecomponents.Thecheckingofcalculations（anddrawingdimensions）isofutmostimportance.Themisplacementofonedecimalpointcanruinanotherwiseacceptableproject.Allaspectsofdesignworkshouldbecheckedandrechecked.

Thecomputerisatoolhelpfultomechanicaldesignerstolightentediouscalculations,andprovideextendedanalysisofavailabledata.Interactivesystems,basedoncomputercapabilities,havemadepossibletheconceptsofcomputeraideddesign（CAD）andcomputer-aidedmanufacturing（CAM）.Howdoesthepsychologistfrequentlydiscusscausesthemachinewhichthepeopleadaptsthemtooperate.Designspersonnel''sbasicresponsibilityisdiligentlycausesthemachinetoadaptthepeople.Thiscertainlyisnotaneasywork,becausecertainlydoesnothavetoallpeopletosayinfactallisthemostsuperioroperatingareaandtheoperatingprocess.Anotherimportantquestion,projectengineermustbeabletocarryontheexchangeandtheconsultationwithotherconcernedpersonnel.Intheinitialstage,designsthepersonneltohavetocarryontheexchangeandtheconsultationonthepreliminarydesignwiththeadministrativepersonnel,andisapproved.Thisgenerallyisthroughtheoraldiscussion,theschematicdiagramandthewritingmaterialcarrieson.

Iffrontsues,themachinedesigngoalistheproductioncanmeetthehumanneedtheproduct.Theinvention,thediscoveryandtechnicalknowledgeitselfcertainlynotnecessarilycanbringtheadvantagetothehumanity,onlyhaswhentheyareappliedcanproduceontheproductthebenefit.Thus,shouldrealizetocarriesonbeforethedesigninaspecificproduct,mustfirstdeterminewhetherthepeopledoneedthiskindofproduct

Mustregardasthe