ansoft后处理过程中计算器使用方法英文版.docx

ansoft后处理过程中计算器使用方法英文版.docx

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ansoft后处理过程中计算器使用方法英文版

ANSOFTMAXWELL2D/3D

FIELDCALCULATOR

-Examples-

Introduction

Thismanualisintendedasanaddendumtotheon-linedocumentationregardingPost-processingingeneralandtheFieldCalculatorinparticular.TheFieldCalculatorcanbeusedforavarietyoftasks,howeveritsprimaryuseistoextendthepost-processingcapabilitieswithinMaxwellbeyondthecalculation/plottingofthemainfieldquantities.TheFieldCalculatormakesitpossibletooperatewithprimaryvectorfields（suchasH,B,J,etc）usingvectoralgebraandcalculusoperationsinawaythatisbothmathematicallycorrectandmeaningfulfromaMaxwell’sequationsperspective.

TheFieldCalculatorcanalsooperatewithgeometryquantitiesforthreebasicpurposes:

-plotfieldquantities（orderivedquantities）ontogeometricentities;

-performintegration（line,surface,volume）ofquantitiesoverspecifiedgeometricentities;

-exportfieldresultsinauserspecifiedboxoratauserspecifiedsetoflocations（points）.

Anotherimportantfeatureofthe（field）calculatoristhatitcanbefullymacrodriven.Alloperationsthatcanbeperformedinthecalculatorhaveacorresponding“image”inoneormorelinesofmacrolanguagecode.Post-processingmacrosarewidelyusedforrepetitivepost-processingoperations,forsupportpurposesandincaseswhereOptimetricsisusedandpost-processingmacrosprovidesomequantityrequiredintheoptimization/parameterizationprocess.

Thisdocumentdescribesthemechanicsofthetoolsaswellasthe“softer”sideofitaswell.So,apartfromdescribingthestructureoftheinterfacethisdocumentwillshowexamplesofhowtousethecalculatortoperformmanyofthepost-processingoperationsencounteredinpractical,daytodayengineeringactivityusingMaxwell.Examplesaregroupedaccordingtothetypeofsolution.Keepinmindthatmostoftheexamplescanbeeasilytransposedintosimilaroperationsperformedwithsolutionsofdifferentphysicalnature.Alsomostofthedescribedexampleshaveeasytofind2Dversions.

1.Descriptionoftheinterface

TheinterfaceisshowninFig.I1.Itisstructuredsuchthatitcontainsastackwhichholdsthequantityofinterestinstackregisters.Anumberofoperationsareintendedtoallowtheusertomanipulatethecontentsofthestackorchangetheorderofquantitiesbeingholdinstackregisters.Thedescriptionofthefunctionalityofthestackmanipulationbuttons（andofthecorrespondingstackcommands）ispresentedbelow:

-Pushrepeatsthecontentsofthetopstackregistersothataftertheoperationthetwotoplinescontainidenticalinformation;

-Popdeletesthelastentryfromthestack（deletesthetopofthestack）;

-RlDn（rolldown）isa“circular”movethatmakesthecontentsofthestacksslidedownonelinewiththebottomofthestackadvancingtothetop;

-RlUp（rollup）isa“circular”movethatmakesthecontentsofthestacksslideuponelinewiththetopofthestackdroppingtothebottom;

-Exch（exchange）producesanexchangebetweenthecontentsofthetwotopstackregisters;

-Clearclearstheentirecontentsofallstackregisters;

-Undoreversestheresultofthemostrecentoperation.

Stack&stackregisters

Calculatorbuttons

Stackcommands

Fig.I1FieldCalculatorInterface

TheusershouldnotethatUndooperationscouldbenesteduptothelevelwhereabasicquantityisobtained.

Thecalculatorbuttonsareorganizedinfivecategoriesasfollows:

-Inputcontainscalculatorbuttonsthatallowtheusertoenterdatainthestack;sub-categoriescontainsolutionvectorfields（B,H,J,etc.）,geometry（point,linesurface,volume）,scalar,vectororcomplexconstants（dependingonapplication）orevenentiref.e.m.solutions.

-Generalcontainsgeneralcalculatoroperationsthatcanbeperformedwith“general”data（scalar,vectororcomplex）,iftheoperationmakessense;forexampleifthetoptwoentriesonthestackaretwovectors,onecanperformtheaddition（+）butnotmultiplication（*）;indeed,withvectorsonecanperformadotproductoracrossproductbutnotamultiplicationasitispossiblewithscalars.

-Scalarcontainsoperationsthatcanbeperformedonscalars;exampleofscalarsarescalarconstants,scalarfields,mathematicaloperationsperformedonvectorwhichresultinascalar,componentsofvectorfields（suchastheXcomponentofavectorfield）,etc.

-Vectorcontainsoperationsthatcanbeperformedonvectorsonly;exampleofsuchoperationsarecrossproduct（oftwovectors）,div,curl,etc.

-Outputcontainsoperationsresultinginplots（2D/3D）,graphs,dataexport,dataevaluation,etc.

Asarule,calculatoroperationsareallowediftheymakesensefromamathematicalpointofview.Therearesituationshoweverwherethecontentsofthetopstackregistersshouldbeinacertainorderfortheoperationtoproducetheexpectedresult.Theexamplesthatfollowwillindicatethestepstobefollowedinordertoobtainthedesiredresultinanumberoffrequentlyencounteredoperations.Theexamplesaregroupedaccordingtothetypeofsolution（solver）used.Theyaretypicalmedium/higherlevelpost-processingtaskthatcanbeencounteredincurrentengineeringpractice.ThroughoutthismanualitisassumedthattheuserhasthebasicskillsofusingtheFieldCalculatorforbasicoperationsasexplainedintheon-linetechnicaldocumentationand/orduringAnsoftbasictraining.

Note:

Thef.e.m.solutionisalwaysperformedintheglobal（fixed）coordinatesystem.Theplotsofvectorquantitiesarethereforerelatedtotheglobalcoordinatesystemandwillnotchangeifalocalcoordinatesystemisdefinedwithadifferentorientationfromtheglobalcoordinatesystem.

Thesameruleapplieswiththelocationofuserdefinedgeometryentitiesforpost-processingpurposes.Forexamplethefieldvalueatauser-specifiedlocation（point）doesn’tchangeifthe（local）coordinatesystemismovedaround.Thereasonforthisisthatthecoordinatesofthepointarerepresentedintheglobalcoordinatesystemregardlessofthecurrentlocationofthelocalcoordinatesystem.

ElectrostaticExamples

ExampleES1:

Calculatethechargedensitydistributionandtotalelectricchargeonthesurfaceofanobject

Description:

Assumeanelectrostatic（3D）applicationwithseparatemetallicobjectshavingappliedvoltagesorfloatingvoltages.Thetaskistocalculatethetotalelectricchargeonanyoftheobjects.

a）Calculate/plotthechargedensitydistributionontheobject;thesequenceofcalculatoroperationsisdescribedbelow:

-Qty->D（loadDvectorintothecalculator）;

-Geom->Surface…（selectthesurfaceofinterest）->OK

-UnitVec->Normal（createsthenormalunitvectorcorrespondingtothesurfaceofinterest）

-Dot（createsthedotproductbetweenDandtheunitnormalvectortothesurfaceofinterest,equaltothesurfacechargedensity）

-Geom->Surface…（selectthesurfaceofinterest）->OK

-Plot

b）Calculatethetotalelectricchargeonthesurfaceofanobject

-Qty->D（loadDvectorintothecalculator）;

-Geom->Surface…（selectthesurfaceofinterest）->OK

-Normal

-

-Eval

ExampleES2:

CalculatetheMaxwellstressdistributiononthesurfaceofanobject

Description:

Assumeanelectrostaticapplication（forex.aparallelplatecapacitorstructure）.ThesurfaceofinterestandadjacentregionshouldhaveafinefiniteelementmeshsincetheMaxwellstressmethodforcalculationtheforceisquitesensitivetomesh.

TheMaxwellelectricstressvectorhasthefollowingexpressionforobjectswithoutelectrostrictiveeffects:

wheretheunitvectornisthenormalvectortothesurfaceofinterest.Thesequenceofcalculatorcommandsnecessarytoimplementtheaboveformulaisgivenbelow.

-Qty->D

-Geom->Surface…（selectthesurfaceofinterest）->OK

-UnitVec->Normal（createsthenormalunitvectorcorrespondingtothesurfaceofinterest）

-Dot

-Qty->E

-*（multiply）

-Geom->Surface…（selectthesurfaceofinterest）->OK

-UnitVec->Normal（createsthenormalunitvectorcorrespondingtothesurfaceofinterest）

-Num->Scalar（0.5）OK

-*

-Const->Epsi0

-*

-Qty->E

-Push

-Dot

-*

--（minus）

-Geom->Surface…（selectthesurfaceofinterest）->OK

-Plot

IfanintegrationoftheMaxwellstressistobeperformedoverthesurfaceofinterest,thenthePlotcommandaboveshouldbereplacedwiththefollowingsequence:

-Normal

-

-Eval

Note:

Thesurfaceinalltheabovecalculatorcommandsshouldlieinfreespaceorshouldcoincidewiththesurfaceofanobjectsurroundedbyfreespace（vacuum,air）.Itshouldalsobenotedthattheabovecalculationsholdtrueingeneralforanyinstancewhereavolumedistributionofforcedensityisequivalenttoasurfacedistributionofstress（tension）:

whereTnisthelocaltensionforceactingalongthenormaldirectiontothesurfaceandFisthetotalforceactingonobject（s）inside.

Theaboveresultsfortheelectrostaticcaseholdformagnetostaticapplicationsiftheelectricfieldquantitiesarereplacedwithcorrespondingmagneticquantities.

CurrentflowExamples

ExampleCF1:

Calculatetheresistanceofaconductionpathbetweentwoterminals

Description:

AssumeagivenconductorgeometrythatextendsbetweentwoterminalswithappliedDCcurrents.

InDCapplications（staticcurrentflow）onefrequentquestionisrelatedtothecalculationoftheresistancewhenonehasthefieldsolutiontotheconduction（currentflow）problem.TheformulafortheanalyticalcalculationoftheDCresistanceis:

wheretheintegraliscalculatedalongcurveC（betweentheterminals）coincidingwiththe“axis”oftheconduct