机械专业英文翻译.docx

机械专业英文翻译

第一篇：机械专业英文翻译DesignofmachineandmachineelementsMachinedesignMachinedesignistheartofplanningordevisingneworimprovedmachinestoaccomplishspecificpurposes.Ingeneral,amachinewillconsistofacombinationofseveraldifferentmechanicalelementsproperlydesignedandarrangedtoworktogether,asawhole.Duringtheinitialplanningofamachine,fundamentaldecisionsmustbemadeconcerningloading,typeofkinematicelementstobeused,andcorrectutilizationofthepropertiesofengineeringmaterials.Economicconsiderationsareusuallyofprimeimportancewhenthedesignofnewmachineryisundertaken.Ingeneral,thelowestover-allcostsaredesigned.Considerationshouldbegivennotonlytothecostofdesign,manufacturethenecessarysafetyfeaturesandbeofpleasingexternalappearance.Theobjectiveistoproduceamachinewhichisnotonlysufficientlyruggedtofunctionproperlyforareasonablelife,butisatthesametimecheapenoughtobeeconomicallyfeasible.Theengineerinchargeofthedesignofamachineshouldnotonlyhaveadequatetechnicaltraining,butmustbeamanofsoundjudgmentandwideexperience,qualitieswhichareusuallyacquiredonlyafterconsiderabletimehasbeenspentinactualprofessionalwork.DesignofmachineelementsTheprinciplesofdesignare,ofcourse,universal.Thesametheoryorequationsmaybeappliedtoaverysmallpart,asinaninstrument,or,toalargerbutsimilarpartusedinapieceofheavyequipment.Innoease,however,shouldmathematicalcalculationsbelookeduponasabsoluteandfinal.Theyareallsubjecttotheaccuracyofthevariousassumptions,whichmustnecessarilybemadeinengineeringwork.Sometimesonlyaportionofthetotalnumberofpartsinamachinearedesignedonthebasisofanalyticcalculations.Theformandsizeoftheremainingpartsaredesignedonthebasisofanalyticcalculations.Ontheotherhand,ifthemachineisveryexpensive,orifweightisafactor,asinairplanes,designcomputationsmaythenbemadeforalmostalltheparts.Thepurposeofthedesigncalculationsis,ofcourse,toattempttopredictthestressordeformationinthepartinorderthatitmaysagelycarrytheloads,whichwillbeimposedonit,andthatitmaylastfortheexpectedlifeofthemachine.Allcalculationsare,ofcourse,depen