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1、机械设计基础（英汉互译）FundamentalsofMechanicalDesignMechanicaldesignmeansthedesignofthingsandsystemsofthingsandsystemsofamechanicalnature-machines,products,structures,devices,andinstruments.Forthemostpartmechanicaldesignutilizesmathematics,thematerialsscicnces,andthecngineering-rnoc
2、hanicsscienccs・Thetotaldesignprocessisofinteresttous.Howdoesitbegin?Doestheengineersimplysitdownathisdeskwithablanksheetofpaper?And,ashejotsdownsomeideas,whathappensnext?Whatfeictorsinfluenceorcontrolthedecisionswhichhavetobemade?Finally,then,howdoesthisdesignprocessend?So
3、metimes,butnotalways,designbeginswhenanengineerrecognizesaneedanddecidestodosomethingaboutit.Recognitionoftheneedphrasingitinsomanywordsoftenconstituteahighlycreativeactbecausetheneedmaybeonlyavaguediscontent,afeelingofuneasiness,orasensingthatsomethingisnotright>Theneedis
4、usuallynotevidentatall.Forexample,theneedtodosomethingaboutafood-packagingmachinemaybeindicatedbythenoiselevel,bythevariationinpackageweight,andbyslightbutperceptiblevariationsinthequalityofthepackagingorwrap・Thereisadistinctdifferencebetweenthestatementofthestatementofthe
5、needancltheidentifiegtionoftheproblemwhichfollowsthisstatement.Theproblemismorespecific.Iftheneedisforcleanerair,theproblemmightbethatofreducingthedustdischargefrompower-plantstacks,orreducingthequantityofirritant’sfromautomotiveexhausts.Definitionoftheproblemmustincludeal
6、lthespecificationsforthethingthatistobedesignedThespecificationsaretheinputandoutputquantities,thecharacteristicsanddimensionsofthespacethethingmustoccupyandal1the1imitationsonthesequantities.Wecanregardthethingtobedesignedassomethinginablackbox.Inthiscasewemustspecifythei
7、nputsandoutputsoftheboxtogetherwiththeircharacteristicsandlimitations.Thespecificationsdefinethecost,thenumbertobemanufactured,theexpectedlife,therange,theoperatingtemperature,andthereliability.Therearemanyimp1iedspecificationswhichresulteitherfromthedesignersparticularenv
8、ironnient.orfromtheproblemitself.Themanufacturingprocesseswhichareavailable,togethetwitht
