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1、附录英文翻译KinematicsanddynamicsofmachineryOneprincpleaimofkinemaricsistocreatthedesignedmotionsofthesubjectmechanicalpartsandthenmathematicallycomputethepositions,velocities,andaccelerations,whichthosemotionswillcreatontheparts.Since,formostearthboundmechanica
2、lsystems,themassremainsessentiallyconstantwithtime,definingtheaccelerationsasafunctionoftimethenalsodefinesthedynamicforcesasafunctionoftime.Stress,inturn,willbeafunctionofbothappliedandinerialsforces.sinceengineeringdesignischargedwithcreatingsystemswhich
3、willnotfailduringtheirexpectedservicelife,thegoalistokeepstresseswithinacceptablelimitsforthematerialschosenandtheenvironmentalconditionsencountered.Thisobviselyrequiesthatallsystemforcesbedefinedandkeptwithindesiredlimits.Inmechinery,thelargestforcesencou
4、nteredareoftenthoseduetothedynamicsofthemachineitself.Thesedynamicforcesareproportionaltoacceletation,whichbringsusbacktokinematics,thefoundationofmechanicaldesign.Verybasicandearlydecisionsinthedesignprocessinvovlingkinematicswiiprovetroublesomeandperform
5、badly.Anymechanicalsystemcanbeclassifiedaccordingtothenumberofdegreeoffreedomwhichitpossesses.thesystemsDOFisequaltothenumberofindependentparameterswhichareneededtouniquelydefineitsposioninspaceatanyinstantoftime.Arigidbodyfreetomovewithinareferenceframewi
6、ll,inthegeneralcase,havecomplexmotoin,whichissimultaneouscombinationofrotationandtranslation.Inthree-dimensionalspace,theremayberotationaboutanyaxisandalsosimultaneoustranslationwhichcanberesoledintocomponentionalongthreeaxes,inaplane,ortwo-dimentionalspac
7、e,complexmotionbecomesacombinationofsimultaneousalongtwoaxesintheplane.Forsimplicity,wewilllimitourpresentdiscusstionstothecaseofplanarmotion:Purerotationthebodypessessesonepoint(centerofrotation)whichhasnomotionwithrespecttothestationaryframeofreference.A
8、llotherpointsonthebodydescribearcsaboutthatcenter.Areferencelinedrawnonthebodythroughthecenterchangesonlyitsangulaiorientation.Puretranslationallpointsonthebodydescribeparallelpaths.Areferencelinedrawnonthebo
