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1、FundamentalsofMechanicalDesignMechanicaldesignmeansthedesignofthingsandsystemsofthingsandsystemsofamechanicalnature-machines,products,structures,devices,andinstruments.Forthemostpartmechanicaldesignutilizesmathematics,thematerialssciences,andtheengineering-mechan
2、icssciences.Thetotaldesignprocessisofinteresttous.Howdoesitbegin?Doestheengineersimplysitdownathisdeskwithablanksheetofpaper?And,ashejotsdownsomeideas,whathappensnext?Whatfactorsinfluenceorcontrolthedecisionswhichhavetobemade?Finally,then,howdoesthisdesignprocess
3、end?Sometimes,butnotalways,designbeginswhenanengineerrecognizesaneedanddecidestodosomethingaboutit.Recognitionoftheneedphrasingitinsomanywordsoftenconstituteahighlycreativeactbecausetheneedmaybeonlyavaguediscontent,afeelingofuneasiness,orasensingthatsomethingisno
4、tright.Theneedisusuallynotevidentatall.Forexample,theneedtodosomethingaboutafood-packagingmachinemaybeindicatedbythenoiselevel,bythevariationinpackageweight,andbyslightbutperceptiblevariationsinthequalityofthepackagingorwrap.Thereisadistinctdifferencebetweenthest
5、atementofthestatementoftheneedandtheidentificationoftheproblemwhichfollowsthisstatement.Theproblemismorespecific.Iftheneedisforcleanerair,theproblemmightbethatofreducingthedustdischargefrompower-plantstacks,orreducingthequantityofirritantsfromautomotiveexhausts.D
6、efinitionoftheproblemmustincludeallthespecificationsforthethingthatistobedesigned.Thespecificationsaretheinputandoutputquantities,thecharacteristicsanddimensionsofthespacethethingmustoccupyandallthelimitationsonthesequantities.Wecanregardthethingtobedesignedassom
7、ethinginablackbox.Inthiscasewemustspecifytheinputsandoutputsoftheboxtogetherwiththeircharacteristicsandlimitations.Thespecificationsdefinethecost,thenumbertobemanufactured,theexpectedlife,therange,theoperatingtemperature,andthereliability.Therearemanyimpliedspeci
8、ficationswhichresulteitherfromthedesigner’sparticularenvironmentorfromtheproblemitself.Themanufacturingprocesseswhichareavailable,togetherwiththefacilitiesofac
