资源描述：
《机械类外文文献》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。
1、.附：外文翻译外文原文：FundamentalsofMechanicalDesignMechanicaldesignmeansthedesignofthingsandsystemsofamechanicalnature—machines,products,structures,devices,andinstruments.Forthemostpartmechanicaldesignutilizesmathematics,thematerialssciences,andtheengineering-mech
2、anicssciences.Thetotaldesignprocessisofinteresttous.Howdoesitbegin?Doestheengineersimplysitdownathisdeskwithablanksheetofpaper?And,ashejotsdownsomeideas,whathappensnext?Whatfactorsinfluenceorcontrolthedecisionswhichhavetobemade?Finally,then,howdoesthisdes
3、ignprocessend?Sometimes,butnotalways,designbeginswhenanengineerrecognizesaneedanddecidestodosomethingaboutit.Recognitionoftheneedandphrasingitinsomanywordsoftenconstituteahighlycreativeactbecausetheneedmaybeonlyavaguediscontent,afeelingofuneasiness,ofasen
4、singthatsomethingisnotright.Theneedisusuallynotevidentatall.Forexample,theneedtodosomethingaboutafood-packagingmachinemaybeindicatedbythenoiselevel,bythevariationsinpackageweight,andbyslightbutperceptiblevariationsinthequalityofthepackagingorwrap.Thereisa
5、distinctdifferencebetweenthestatementoftheneedandtheidentificationoftheproblem.Whichfollowsthisstatement?Theproblemismorespecific.Iftheneedisforcleanerair,theproblemmightbethatofreducingthedustdischargefrompower-plantstacks,orreducingthequantityofirritant
6、sfromautomotiveexhausts.Definitionoftheproblemmustincludeallthespecificationsforthethingthatistobedesigned.Thespecificationsaretheinputandoutputquantities,thecharacteristicsofthespacethethingmustoccupyandallthelimitationsonthesequantities.Wecanregardtheth
7、ingtobedesignedassomethinginablackbox.Inthiscasewemustspecifytheinputsandoutputsoftheboxtogetherwiththeircharacteristicsandlimitations.Thespecificationsdefinethecost,thenumbertobemanufactured,theexpectedlife,therange,theoperatingtemperature,andthereliabil
8、ity.Therearemanyimpliedspecificationswhichresulteitherfromthedesigner'sparticularenvironmentorfromthenatureoftheproblemitself.Themanufacturingprocesseswhichareavailable,togetherwiththefacilitiesofacertainplant,const
