Magnetic-Field-Analysis-of-MSMA-Actuator-Based-on-

MagneticFieldAnalysisofMSMAActuatorBasedOnANSYSHua-weiJi1SchoolofMechanicalEngineeringHangzhouDianziUniversityHangZhou,ChinaEmail:[e-mail]-qingWen2SchoolofMechanicalEngineeringHangzhouDianziUniversityHangZhou,ChinaEmail:[e-mail]—ThemagneticallycontrolledShapeMemoryalloy(MSMA)isanewtypeofintelligentmaterials,whichhaslargestrainandhighefficiencyofelectromechanicalenergyconversion,butatthistimeitisnotactuallyusedasactuators.SointhispaperwemainlyexpoundedtheworkingprincipleofMSMAactuatorandcompletedmagneticfieldanalysisofitbasedonANSYS.ThepaperprovidesreferenceforthestructuredesignandmaterialselectionforMSMAactuator;meanwhile,itacceleratestheMSMAactuatordesignprocess.Keywords—MSMA;MSMAactuator;magneticfieldanalysis;ANSYSI.INTRODUCTIONDuringthepasttwodecades,withtherapidlydevelopmentoftheminiaturerobotandthecomputercontroltechnology,microdisplacementactuatorrequestslighterweight,smallervolumeandhighresponsefrequency.Inrecentyears,TheMSMA(Magneticallycontrolledshapememoryalloy)isfoundwhichisanewtypeofintelligentmaterials.Ithaslargestrainandhighefficiencyofelectromechanicalenergyconversion,Howevershapememoryalloyandpiezoelectrichaven't.Atthistimetheyarenotactuallyveryusedasactuators,Buttoitsresearchismainlyconcentratedinmicrostructure,temperature,materialcompositionandinducedstrainetcathomeandabroad[7].Conversely,inthispapertheMagneticShapeMemoryAlloy(MSMA)exploitedhasbeeninventedveryrecently.MSMAgeneratestressandchangetheirshapeinthemagneticfieldandthedeformationofthesematerialscanbeaslargeas10%(likeShapeMemoryAlloy,SMA),amagnetostrictioncoefficientthatisalmosttwoorderofmagnitudehigherthatterreneone.Moreover,differentlyfromclassicalShapeMemoryAlloys(SMA),actuatedbytemperature,theynormallyshowquitefastresponsesbeingthemactuatedbymagneticfieldsandnotbytemperature[1,2].Thereforeit'ssignificancetostudytheintelligentmaterial.ThispaperwemainlyexpoundedtheworkingprincipleofMSMAactuatorandcompleteditsmagnetic-fieldanalysisbasedonANSYS.PRINCIPLEANDSTRUCTUREDESIGNFORMSMAACTUATORTheMSMAactuatorpropertiesmostlydependonthedeformationofmaterialandstrengthofthemagnetization.Thedirectionbetweensurroundingmagneticfieldandmechanicalmotionisvertical[3,4],Whenthemagneticfieldisaddedinthedirectionofaxisvertically,MSMAiselongatedtomakethemovingaxismoveright,showninFig.1.Howeveraftergettingridofthemagneticfieldinverticaldirection,Thespringtomakethemovingaxismoveleft.Fig.1ModelofMSMAactuatorTheMagneticfieldiscontrolledbycoilcurrent,andthespringprovidesrestoringforceforMSMA.Movingaxisisfixedinthefrontofthedisplacementsensor,atthesametimepressuresensorisfixedatthebottomofLower-mould.Wecanadjustcurrentbythedetectiondataofthedisplacementsensorandpressuresensor.ForMSMAwhenweimposeexternalmagnetictothecrystal,magneticfieldvectorwilltendtocytoplasmmagnetizationdirection[6].Inordertopreventtheoutstretchedpoleandtheupper-mouldjamming,wemustensurethattheyhavegoodcoaxialtolerance,meanwhilewecanchangepreloadingbyrotatingthePre-tighteningscrews.Fig.2.showsactuatingmechanismforMSMAactuator,andFig.3.showstruepictureofMSMAactuator.Fig.2.actuatingmechanismforMSMAactuator1-Movingaxis2-Pre-tighteningscrews3-Spring4-Upper-mould5-MSMA6-Lower-mould7-Pressuresensor2010InternationalSymposiumonComputationalIntelligenceandDesign978-0-7695-4198-3/10$26.00©2010IEEEDOI10.1109/ISCID.2010.331052010InternationalSymposiumonComputationalIntelligenceandDesign978-0-7695-4198-3/10$26.00©2010IEEEDOI10.1109/ISCID.2010.331052010InternationalSymposiumonComputationalIntelligenceandDesign978-0-7695-4198-3/10$26.00©2010IEEEDOI10.1109/ISCID.2010.331052010InternationalSymposiumonComputationalIntelligenceandDesign978-0-7695-4198-3/10$26.00©2010IEEEDOI10.1109/ISCID.2010.331052010InternationalSymposiumonComputationalIntelligenceandDesign978-0-7695-4198-3/10$26.00©2010IEEEDOI10.1109/ISCID.2010.331052010InternationalSymposiumonComputationalIntelligenceandDesign978-0-7695-4198-3/10$26.00©2010IEEEDOI10.1109/ISCID.2010.3388Fig.3.TruepictureofMSMAactuatorSIMULATIONRESULTSANDANALYSISAlmost60yearshavepassedsincethewordfiniteelementwascoinedanditsfirstcomputerapplicationmade,butprogresscontinuesbothinthemethodologyitselfandintherangeofitsapplication.Finiteelementmethod(FEM)isdevelopedquicklyafterbeingbroughtforwardin1953.Thefieldofapplicationhasenlargedsteadilyfromstructuralmechanicstoareasoffluidmechanics,electromagneticphysicsandnuclearengineering.Eachoneoftheseareashasposednewproblemsmanyofsuchthesefeedingbacktothebasicknowledgeandoftengivinganewperspectivetooldproblems.For3Dstaticelectromagneticanalysis,currentsourceistreatedasasingleunitanditneedn'ttobuildandmesh.Accordinglymodelingiseasier,andcurrentsourceelementcansimulateitseffecttomagnetic-field.Thespecificstepsoftheanalysis:a.Creatingphysicalenvironment;b.Modeling,meshingandexertingmeshattributes;c.Usingtheelectromagneticmacros-RACEtomodelcoil;d.UsingDSPmethodtosolve;e.Savedatabase;f.Lookingresultbygeneralpostproc.A.FINITEELEMENTMODELThesoftwareANSYSisusedtocomputetheelectromagneticfieldmodelt