ansys如何生成adams的模态中性文件.doc

11.3.ExportingtoADAMSAfterbuildingthemodelinANSYS(includingallinterfacepoints),thenextstepistoinvoketheANSYS-ADAMSInterfacetocreatethemodalneutralfile,Jobname.MNF.CreationofthisfileisdrivenbyanANSYScommandmacrocalledADAMS.MAC.Tostarttheinterface,selectthefollowingGUIpath.MainMenu>Solution>ADAMSConnection>ExporttoADAMSTheSelectInterfacePointsdialogboxappearsfirst.Fromthisdialogbox,youmustselecttwoormoreinterfacepoints.NoteDonotchoosetoomanyinterfacepointssinceonepointgivesriseto6degreesoffreedominADAMS.Toomanyinterfacepointsmayleadtohugefilesandmodels.AfteryouconfirmyourselectionbypickingOK,theExporttoADAMSdialogboxappears.Figure11.2ExporttoADAMSDialogBox图形在打开的对话框中，Completethefollowingstepsusingthisdialogbox.1. SystemofModelUnits:TheunitsusedforthemodelisimportanttotheADAMSprogram,whereasANSYSonlyrequiresthatyouuseaconsistentsetofunits.Theunitschosenwillbewrittentothe.MNFfileandcanberecalledwiththeADAMS/Flexmodule.Ifnounitsarespecified,ADAMSassumesthatthesameunitswereusedinANSYSastheoneschosenintheADAMSmodel.Seethe/UNITScommandfordetails.Ifyouspecifyuserdefinedunits,aDefineUserUnitsdialogboxwillappearforyoutoinputtheconversionfactors(forlength,mass,force,andtime)betweenSIunitsandyourchosenunits.Belowisanexampleofuserdefinedunitsinwhichthecomponenthasbeenmodeledusingmillimeter,tonne(metricton),newton,andsecond.LengthFactor=1meter/millimeter=1000MassFactor=1kilogram/tonne=0.001ForceFactor=1newton/newton=1TimeFactor=1second/second=12. NumberofModestoExtract:Inputthenumberofnormalmodestocompute.Normalmodesaretheeigenmodesofthecomponentwithalldegreesoffreedomofallinterfacepointsfixed.ThenumberofnormalmodesdependsonthefrequencyrangeoftheexcitationyouwillapplyinyourADAMSmodel.Youmustchooseasufficientnumberofmodestorepresentyourstructureinthatfrequencyrange.InADAMS,ifyouhavechosentoomanynormalmodes,youareabletodeactivateeigenmodesbasedonthefrequencyoranenergycriterion.3. ElementResults:Specifywhetherornottheprogramshouldwritestressand/orstrainresults.Thisoptionhasnoeffectontheoutputforbeamelements.Ifyouwanttooutputstressandstrainforonlyasubsetofnodes,youshouldcreateanodecomponentnamed""STRESS""beforerunningtheADAMScommandmacro.4. ShellElementResultOutputControl:Specifytheshellelementoutputlocation(top,middle,bottom).Thisoptionhasnoeffectontheoutputforsolidelementsandbeamelements.5. Filename:Specifyafilenameforthemodalneutralfile.ThedefaultnameisJobname.MNF.Ifafilewiththechosennameexists,itwillbemovedtoafilenamedfilename.MNFBAK.6. ExporttoADAMS:Choose“SolveandcreateexportfiletoADAMS”toinitiatethesolutionsequence.StaticandnormalmodesarecomputedandallinformationrequiredbyADAMSiswrittentothe.MNFfilespecifiedabove.Onlytheselectedelementsareconsidered.ThecurrentmodeliswrittentothedatabasefileJobname.DBMNF.NoteNotethatthealgorithmusedtocomputethe.MNFfileaddsconstraintstotheinterfacepoints.Ifyoucreatethe.MNFfileasecondtimeusingthesamemodelinthesamerun,besuretodeleteallconstraintsontheinterfacepoints(orresumethedatabasefileJobname.DBMNF)beforeyourunitagain.11.3.1. ExportingtoADAMSviaBatchModeIfyouprefertoworkinbatchmode,youmaychoosetoruntheADAMScommandmacrobycommandinput.Afterbuildingthemodelanddefininginterfacepoints,usethefollowingcommandstocomputethe.MNFfile./UNITS,LabelNSEL,...SAVESpecifytheunitschosenformodelingSelecttwoormoreinterfacepointsSavethemodelforapossibleresumefromthispointADAMS,NMODES,...ActivateADAMS.MACtocomputethe.MNFfileSeetheADAMScommanddescriptionformoreinformation.Whenyouusecommandinputtocomputethe.MNFfile,thereisnooptiontochangethefilename.ThedefaultnameofJobname.MNFwillbeused.11.3.2. VerifyingtheResultsItisagoodpracticetoverifythecorrectnessoftheresultsafterthe.MNFfileiscreated.Belowareguidelinesyoucanusetocompletethistask.€CheckthenumberoforthonormalizedeigenmodesintheANSYSoutputwindow.Theseeigenmodesaretheresultofanorthonormalizationofthenormalmodesandtheconstraintmodes.Youshouldobservethefollowing:€Thenumberofmodesequalsthenumberofnormalmodesplusthenumberofconstraintmodes.€Thefirstsixmodesarerigidbodymodes.Thesearemarkedwith“(probablerigidbodymode).”Ifthereisamodeclosetoarigidbodymodebutnotmarked,youmaydeactivateitlaterintheADAMSprogram.€Ifamodeismarkedwith“Infinity.Possiblemasssingularity.Ignored,”checkyourmodelcarefully.TheremightbeaproblemwiththeInterfacepoints.€Thefirstfewmodesareequaltothefree-freeeigenmodesofthecomponent.Youmightwanttoverifythisbydoingamodalanalysis:SetanalysisoptiontoANTYPE,MODALwithM0D0PT,LANB(BlockLanczos);activatethelumpedmassapproachwithLUMPM,0N.€Reviewthenormalmodes(loadstep1)andtheconstraintmodes(loadstep2)intheGeneralPostprocessor.€VerifythetransferbydoingamodalanalysisofthecomponentinADAMSwithallinterfacedegreesoffreedomfixed.ComparetheresultswiththenormalmodescomputedinANSYS(loadstep1).11.4.RunningtheADAMSSimulationAfteryouhaveverifiedthatthe.MNFfilecontainsaccurateinformation,youarereadytorunanADAMSsimulationwithaflexiblecomponent.Importthe.MNFfileintoyourADAMSmodelandattachittot。