机械材料外文翻译英文文献材料制备机械设计理论.docx
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机械材料外文翻译英文文献材料制备机械设计理论.docx
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机械材料外文翻译英文文献材料制备机械设计理论
NewTrendsandProblemsinMaterialProcessingMachineDesignTheory
WANGAi-lun,DUANJi-an,HUANGMing-hui,ZHONGJue
(CollegeofMechanical&ElectronicEngineering,
CentralSouthUniversity,Changsha410083,HunanChina)
Abstract:
Basedonreviewingthehistoricalbackground,prospectingforthedevelopmenttrend,analyzingthecomplicacyandmechanismandsummingupsomeachievementsandexperiencesinscientificresearch,severalnewproblemsandthepossibledirectionofdevelopmentinmaterialprocessingtechnologyandmachineareproposed,suchas,producingnewconceptmaterialspossessingsomespecificandextraovdinarypropertiesbymeansofintegratingandcoalescingconelativefrontierscienceandtechnology;andthereafterabriefdiscussionisgiven.
Keywords:
interface;extraordinaryphysicalfield;processionmachine;functionmaterial
1 TheTimeBackgroundofMaterialProcessingMachine
Inthelongspanofhistoryofhumanprogress,manytools,machinesandmethodswerecreatedandavarietyofmaterialswithdifferentpropertieswereprocessed.Materialsanditsprocessinghavebecomeoneofpillaranddrivingforceofmankindprogress.Inpacewithmulti-polarcompetitionincurrentworldandpeople’sstrivingperseveringlyforhappierlife,materialfunctiongoesbeyondunceasinglymen’sknowledgeandimagination,forexample,crypticfunctionmaterial,semiconductormaterial,energymaterial,vibration-absorptivematerial,super-strengthaluminumalloyaccountingfor70percentofapplicationofaeronauticsandspace,metalfoilof4~5μm,deepdrawingplatewithanisotropybelow1percent,electronicaluminumfoilwithmicro-orientationupto95percent,heatresistingaluminumalloywithsuperstrongspecificstrengthusedinaeronautics,spaceanddeepsea,etc.Thusseveralimportantdevelopmenttrendswithdistincttimefeaturesinmaterialprocessingdomainareshapedupasfollows:
(1)Creatingmaterialprocessingmachinewithextraordinaryphysicalfieldforprocessingmaterialwithspecialtexturestructuresandfunctions.Forexample,applicationsofthermalenergyandmechanicalenergyarebreakingthroughunceasinglytechnologylimit,andsomenon-traditionenergy,suchasmicrowave,chemicalenergy,bioenergy,etc.,areintroducedintomaterialprocessingprocedureoneafteranother,sothatsomematerialprocessingmachineswithextraordinaryenergycircumstanceareproduced.
(2)Breakingthroughtraditionalphysicallimitsandintegratingmelting,solidifying,plasticdeformationandheattreatmenttoobtainspecialfunctionofmaterialandcutdownexpenses[3].Forexample,near-netshapingmaterialprocessingtechnology,suchasfastrolling,sprayingdeposition,over-plasticmolding,injectionmolding,highenergybeam,etc,isapplied.
(3)Materialprocessingprocessisforgedaheadinthedirectionofhighspeed,heavy-dutyandhighaccuracyonlinecontrol,forinstance,therollingspeedgoesupto130m·s-1,thedeformationpressurerisesupto300MPa,accuracyofdimensionupto0.1μm,accuracyofshapeupto0.1I,strengthaccuracycomesupto0.1MPa.Forthesereasons,itisnecessaryformaterialprocessingmachinedesigntheorytointegrateandcoalesceingeniouslycorrelativefrontierscienceandtechnologytocreateandproducesomenewconceptmaterialprocessingmachinewithfollowingfunctions.
2 DueFunctionsofNewConceptMaterialProcessingMachine
(1)Tohavetheabilitytoproduceandbearextraordinaryphysicalfieldandtransmitextraordinaryenergyflowwiththeaimofprovidingextraordinaryphysicalcircumstancesnecessaryfornewconceptmaterialprocessing.Forexample,highgradienttemperaturefieldwiththespeedofcool-downofworkinterfacewhichexceeds104~106K·s-1,linewaveandpulsecomplexexertedinsolidifying-deformingarea,super-strengthcontactstressfieldofmaterialforminginterface,turbulentflowfieldofmoltenmetalwithverybigflakinessratio,lowfrequencymagneticfieldwithrandomfrequency,microwavefieldforpowdermetalheating,ultrasonicfieldforlargevolumesolidifying,etc.[4],areapplied.
(2)Tohavetheabilitytoworkincriticalstatesothathighstabilityandidealperformanceofprocessingmachineisensuredunderthecircumstanceofreinforcedtechnologicalconditionandmulti-fieldcouplingoperation.Forexample,chattersuppressingcapabilityoffastultra-thinrollingundertheconditionofboundarylubricatingstate[5],thecapabilityofself-excitedvibrationsuppressingundertheconditionofspecialfrictionstate,synergismstabilityanddisturbancestabilityofflexibleconnectingparallelshaftwithmulti-drivingsystem,etc.[4],areensured.
(3)Tohavetheabilitytoaccuratelycontrolthematerialprocessinginordertoobtainlowloss,highefficiencyandhighqualityofmaterialprocessing.Forexample,super-highaccuracyon-linemonitorofproductsform,on–linemonitorandon-lineadjustmentofproductstextureandproperties,precisioncoordinationcontrolofmulti-procedure,on-linemonitorofmicro-orientationofmetalplasticdeformation,etc.[4],areensured.Someproductsaccuracyindexmaybeenumeratedasfollows:
dimensionalaccuracycomingto0.1μm,microstructureuniformitytocrystallattice,strengtherrorto0.1MPa,etc.[4]Inshort,onlybynewconceptmaterialprocessingmachinewithextraordinaryfunctionbeingdesignedandmade,canspecialfunctionmaterialbeprocessed.
3 ScienceProblemsandStudyContentsofMetalMaterialProcessingMachine
UndertheCircumstanceofExtraordinaryPhysicalField
Inviewofthesefactsandbackgroundmentionedabove,severalnewresearchtopicscanbeadvancedasfollows.
3.1CouplingHeatTransferMechanismofMulti-PhaseInterfaceTemperature-StressField
Abrand-newmicrostructurecanbeobtainedthroughcontinuouslylargedeformationandfastsolidifyingwhenmeltingmetalisincriticalstateofliquidsolid.Atthisverymoment,highdensityheatflowanddynamicheatresistancearepresentinmaterialprocessingcircumstance.Abasictheoryproblemofdesigningthiskindofmachineistostudymechanismofheattransmittanceandenergyconversion,andtoestablishmathematicalmodel.
3.2FrictionConstraintMechanismofPlasticFlowInterfaceofMaterialProcessingMachine
Thecouplingbetweenoperationmechanismandworkpieceisverycomplicatedbecauseplasticflowispresentinprocessinginterface.Theinterfacestate,determinedbyvelocity,loadthermodynamicprocess,elasticityofoperationmechanism,plasticityofworkpiece,dynamicbehaviourofinterfacesticking-slidingandpartialhydrodynamiclubrication,etc,affectandformfrictionconstraintsmechanismpeculiartomaterialprocessingmachine,becausetheseconstraintspresentstrongnon-linearity;andundercertaincircumstances,theconstraintsmaybedestroyedormismatchedinstantaneouslyandthusdynamicinstabilityisresultedin.Thusfollowingproblemscanbeputforward:
Mechanismof“spectrechatter”arosefromsticking-slidingfrictionandpartialhydrodynamiclubricationinrollinginterface,instabilityconditionandmechanismofconstraintbetweensmoothsurfaceandrotatingbodyunderthecircumstanceofhighspeed,heavy-dutyandboundarylubrication,Lubricationfilmabsorptionmechanismandphysicalchemistrybehaviourofinterfaceofunceasinglyregenerativesurface,therelationshipbetweenrheologicalcharacteristicandmachineoperationparameters.
3.3Multi-BodyNon-LinearContactMechanismUndertheConditionofExtra-HighPressureField
Tobuildthesuperstrengthpressurefieldonlargeareaisoneofbasicfunctionofmaterialprocessingmachine,anditisalsonecessarytoformbyoncelarge-sizestructureelement(suchasspacecraft,intercontinentalvehicles,carandlarge-scaleaeroplaneetc).Theabilitytobuildsuperstrongpressurefieldisoneofimportantfeatureandthebaseofindependentnationaldefense.Underthecircumstanceofsuperstrengthpressurefield,multi-bodystrongnonhertzcontactandnon-linearfrictionwillbeproduced,thuslocalpermanentdeformationanddegradingofelementaccuracymaybeled.Newtheoryfoundationofdesignofmachinewithsuperstrengthpressurefieldwillbefurnishedthroughstudyofmulti-bodystrongnon-hertzcontactmechanism,multi-bodynon-linearfrictionmechanism(suchasprovidingforce-displacementmixedsolvingprocessofthree-dimensionmulti-body).
3.4LoadDistributionLawinMulti-SlidingPairWithStructureBiasLoad
Withregardtostaticallyindeterminatestructure,loaddistributionofconstraintpointisdeterminedbydeformationcompatibilitycondition.However,concerningsomeplanelarge-sizestaticallyindeterminatestructurewithslidingdegreeoffreedominthirddimension,loaddistributioncannotbedeterminedbydeformationcompatibilitycondition.Thusnewtheorybasiswillbeprovidedbyanalyzingofcontactbehaviourandmechanismofslidingpair(suchascreep,forceoffriction,integraldeformationcompatibilitycondition,etc).
3.5CouplingMechanismandStabilityofMulti-PhysicalFieldsinMaterialProcessingSystems
Inthewakeofsystemfunctionbecomingmoreandmorediversified,conventionaltechnologylimitsinmaterialprocessingmachineisbeingbrokethroughunceasingly,systemstructurealsobecomesincreasinglycomplicated,andsystemperformancebecomesincreasinglymulti-causal.Forexample,anyinstantaneousstateofrollerinfastrollingmillsisaffectedbyelasticdeformation,plasticflow,heattransferprocess,hydro-dynamiclubricationprocess,interfacephysicalchemistrymolecular
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