SACS Dynamic Response.pdf
Transcript of SACS Dynamic Response.pdf
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Copyright2012byBentleySystems,Inc.Version7.0Revision1
1.0INTRODUCTION
1.1OVERVIEW
TheDynamicResponseprogramisdesignedtocomputethedynamicresponsesofastructuresubjectedtodynamicexcitationduetobasemotionsuchasinanearthquake,ordynamicforcesduetoperiodicvibrationorimpactloads.Theprogramcananalyzebasedrivensystemswithinputdescribedeitherasaspectralinputorasatimehistoryinput,andforcedrivensystemswithinputdescribedbyasetofperiodforcesortimehistoryforces.
1.2PROGRAMFEATURES
DynamicResponseanalysisrequiresdynamicmodeshapeandmassfilesinadditiontoaDynamicResponseinputfile.
Somegeneralfeaturesandcapabilitiesoftheprogrammoduleare:
1.AbilitytouseafullstructuralmodelforuseinDynamicResponseanalysis.
2.Nonlinearfluiddampingeffectsincludedautomatically.
1.2.1Earthquake/BaseDrivenAnalysis
Bothspectralearthquakeandtimehistoryearthquakeanalysesaresupported.Someoftheseismicanalysiscapabilitiesfollow:
SpectralEarthquake
1.APIresponsespectraarebuiltintotheprogram.
2.Supportsuserdefinedresponsespectra.
3.Spectralmotioncanbedescribedasacceleration,velocity,ordisplacement.
4.Modalcombinationsusinglinear,SRSS,peakplusSRSS,orCQCmethods.
5.Abilitytouseadifferentresponsespectrumforeachdirection.
6.Combinesseismicresultswithstaticresultsautomatically.
7.Supportsuserdefinedpowerspectraldensities.
8.Abilitytogenerateresponsefunctionforanyjointdegreeoffreedom.
TimeHistoryEarthquake
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1.Includesearthquaketimehistorylibraries.
2.Userdefinedinputtimehistories.
3.Linear,quadratic,orcubicinterpolationavailableforthetimehistoryinput.
4.Variabletimestepintegrationprocedure.
5.Automaticloadcaseselectionbasedonoverturningmoment,baseshear,etc.
6.Graphicalrepresentationofoutputvariables.
1.2.2ForceDrivenAnalysis
Forcetimehistory,PeriodicandEnginevibrationanalysesaresupported.Themaincapabilitiesandfeaturesforforcedrivenanalysisaredetailedbelow:
ForceTimeHistory
1.Linear,quadratic,orcubicinterpolationavailableforthetimehistoryinput.
2.Inputtimehistoriesmaybesavedtoafile.
3.Automaticloadcaseselectionbasedonoverturningmoment,baseshear,jointdisplacement,etc.
4.Variabletimestepintegrationprocedure.
5.Timehistoryplotsincludingmodalresponses,overturningmoments,baseshear,etc.
6.Generationofequivalentstaticloads.
7.GenerationofincrementalloadsforCollapseanalysis
PeriodicVibration
1.Supportsinputforcesandmomentsappliedtoanypointatvariousfrequenciesandphaseangles.
2.Automaticloadcaseselectionbasedonmaximumjointdisplacementataspecificjointoratalljoints.
3.Fullplotcapabilitiesincludingmodalresponses,overturningmoments,baseshear,etc.
Engine/CompressorVibration
1.Supportsmechanicalunbalancedforcesandgastorquesinadditiontoreciprocatingloads.
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2.Linearand/ornonlinearinterpolationofforcesbetweenrunningspeeds.
3.Usercanselectspecificjointstomonitorormonitoralljoints.
4.JointdisplacementscanbecomparedandplottedversusDline,SNAMEand/orMilitarySpecificationallowables.
5.Allowsuserdefinedphasingofforcesandmomentswithinaloadcase.
6.Canautomaticallycombinemaximumresponseofvariousloadcases.
7.Generatesplotsofinputdataversustimeforanyloadcase.
8.Calculatesperiodicforcesamplitudesandperiodsfromforceversustimeinput.
1.2.3SpectralWindAnalysis
Thewindspectralfatigueandextremewindanalysesaresupported.Someofthespectralwindanalysiscapabilitiesareasfollows:
ExtremeWind
1.Determinesdynamicamplificationfactorsautomatically.
2.Generatescommonsolutionfilecontaininginternalloads,stresses,reactionsanddisplacementsmultipliedbyitsowndynamicamplificationfactor.
3.IncludescrosscorrelationofmodalresponsesusingtheCompleteQuadraticCombination(CQC)modalcombinationtechnique.
4.Plotsgeneralizedforcespectrumandresponsespectrumforeachwindspeed.
5.UsesHarrisWindspectrum.
WindFatigue
1.UsesHarrisWindspectrum.
2.OptionallycreatesFatigueinputfileautomatically.
3.DistributeswindspeedutilizingaWeibulldistribution.
4.AssumesRayleighdistributionofRMSstresses.
5.Handlesmultiplewinddirectionsinsameanalysisexecution.
1.2.4IceForceAnalysis
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IceVibration
Theicevibrationanalysiscapabilityincludesthefollowingfeatures:
1.Automaticallyincludesicestiffness.
2.Maximumandminimumpeakselection.
3.Automaticcyclecountforfatigueanalyses.
4.Createsfatigueinputdataautomatically.
5.Fullplotcapabilitiesincludingiceforces,modalresponses,overturningmoments,baseshear,etc.
6.Variabletimestepintegrationprocedure.
1.2.5DynamicImpactAnalysis
Thedynamicimpactanalysiscapabilityincludesthefollowingfeatures:
1.Dynamicshipimpactanddroppedobjectanalysiscapabilities
2.Timehistoryplotsincludingmodalresponses
3.Generationofequivalentstaticloadsforstaticanalysis..
4.GenerationofincrementalloadsforCollapseanalysis
1.3PROGRAMSTRUCTURE
TheDynamicResponseprogramcanbeusedtosolvebasemotiontimehistoryorforcedrivensystems.
1.3.1BaseDrivenSystems
Thebasemotiontimehistorysolutionutilizesavariablestepintegrationprocedurethatdeterminesthelargesttimestepsizeallowedforeachsituationsuchthatresultsarewithinaspecifiedaccuracywhileanalysisexecutiontimeisoptimized.Thisprocedureallowstheprogramtousesmalltimestepsonlywhererequiredsuchasatpointsofrapidchanges.Theprocesscanalsoaccountforfluiddampingforsubmergedstructuresbyusinganequivalentfluiddampingasanalternativetocalculatingtheactualfluidforcesateachstepduringtheintegrationprocess.
1.3.2ForceDrivenSystems
Forforcedrivensystems,theDynamicResponseprogramcanpredicttheresponsesduetoasetofperiodicforcesandmomentsappliedtomultiplepointsonthe
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structure.Theseforcescanbeatdifferentfrequenciesandphaseswithrespecttoeachother.Fortimehistoryforceinput,thesamevariablestepintegrationprocedureutilizedforbasedrivensystemsisusedtocalculatetheresponses.
ImpactAnalysis
TheDynamicResponsemodulecanpredicttheresponseofstructureresultingfromaimpactfromavesseloradroppedobject.Theprocesscanalsoaccountforfluiddampingforasubmergedportionofthestructurebyusingeitheranequivalentfluiddampingoralternativelytheprogramcancalculatetheactualfluidforcesateachstepduringtheintegrationprocess.
2.0ANALYSISPROCEDURE
TheDynamicResponseprogramisgenerallyusedtomodalresponsesintheformofvelocity,acceleration,displacementorstress.Thissectiondetailstheanalysisprocedureusedtodeterminethemodalresponsesforthefollowing:
A.BaseDrivenSystems
B.ForceDrivenSystems
C.SpectralWind
D.IceForce
E.DynamicImpactAnalysis
TheDynamicResponseprogramrequiresaDynpacmodeshapefile,DynpacmassfileandaDynamicResponseinputfile.Thefollowingdetailstheinputforthevarioustypesofdynamicanalyses.
2.1BASICANALYSISOPTIONS
Regardlessoftheanalysistype,basicanalysisoptionsmustbespecifiedintheDynamicResponseinputfile.
2.1.1AnalysisType
Theanalysistypeisenteredincolumns710ontheDROPTline.EnterSPEC,TIME,VIBR,WINDorENGVforspectralearthquake,timehistoryearthquake,forcedrivenperiodicortimehistory,spectralwindorenginevibrationanalysis,respectively.Enter'TCLP'togenerateincrementalloadsforforce/timehistorycollapseanalysis,enter'SHIP'fordynamicshipimpactanalysisorenter'DROP'fordynamicdroppedobjectanalysis.
2.1.2Damping
Dampingfactorscanhaveaprofoundeffectonanalysisresults.Theprogramhastheabilitytoconsiderbothstructuralandfluiddamping.
StructuralDamping
StructuraldampinginputisrequiredforanyresponseanalysisandisinputusingtheSDAMPline.Forsinglepassanalyses,thestructuraldampingvalueinputonthe
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SDAMPlineshouldincludeallsourcesofdampingincludingfluiddampingifapplicable.
Note:FluiddampingmayoptionallybespecifiedormaybecalculatedautomaticallyusingtheFDAMPline.Whenfluiddampingiseitherspecifiedorcalculatedbytheprogram,thedampingvaluesontheSDAMPlineshouldnotincludeanydampingduetothefluid.
Ifallmodeshavethesamedamping,theoveralldampingasapercentofcriticalisinputincolumns1115ontheSDAMPlineandcolumns2170shouldbeleftblank.Thefollowingshowstotalcriticaldampingof3.0%forallmodes:
Ifthedampingvalueisdifferentforvariousmodes,thedampingvalueforeachmodemustbespecifiedintheappropriatecolumns.Dampingvaluesmustbespecifiedforeachmodeandmustbeexpressedasanonzeropositivenumber.Thesamplebelowshowsvariousdampingvaluesforthe15modestobeincludedintheanalysis.
FluidDamping
Fluiddampingmaybeoptionallyconsideredduringmostdynamicresponseanalysis.Theprogramhastheabilitytocalculatefluidmodaldampingautomaticallyortousedampingvaluesinputbytheuser.FluiddampingoptionsarespecifiedontheFDAMPlinefollowingtheSDAMPline.
CalculatingFluidDampingAutomatically
Whenfluiddampingiscalculatedbytheprogram,thevaluesarebasedonthenonlinearforcesonthestructure.Forspectralanalysis,anequivalentdampingratioisdeterminedbasedonaparticularamplitude.
EnterPCincolumns78iftheprogramistocalculatefluiddampingautomatically.Ifnonlineardampingistobeused,enterNLincolumns910.Fortimehistoryanalyses,entertheamplitudeincolumns1620ifaspecificamplitudeistobeusedtocalculatefluiddamping.
SpecifyingFluidDampingDirectly
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Fluiddampingvaluesmaybespecifieddirectlybytheuser.Ifallmodeshavethesamefluiddamping,theoveralldampingasapercentofcriticalisinputincolumns1115ontheFDAMPlineandcolumns2170shouldbeleftblank.Thefollowingshowsfluiddampingof2.0%forallmodes:
Ifthedampingvalueisdifferentforvariousmodes,thedampingvalueforeachmodemustbespecifiedintheappropriatecolumns.Dampingvaluesmustbespecifiedforeachmodeandmustbeexpressedasanonzeropositivenumber.
Note:Forsinglepassanalysis,fluiddampingmustbeincludedinthevaluespecifiedforstructuraldampingontheSDAMPline.
2.1.3ModeSelection
Bydefault,theresponseofallmodesisconsideredinthedynamicresponseanalysis.Iftheresponseofsomemodesistobeignored,thenumberofmodestoconsidershouldbestipulatedincolumns1114ontheDROPTline.Whenthenumberofmodesnisspecified,theprogramassumesthatthefirstnmodesaretobeconsideredunlessmodenumbersaredesignatedusingtheMODSELinputline.Forexample,thefollowingdesignatesthatmodes110andmodes1620aretobeconsideredintheanalysis.
Note:ThenumberofmodesspecifiedontheMODSELlinemustbeequaltothenumberofmodesdesignatedontheDROPTline.
2.1.4VerticalCoordinate
Thepositiveverticalcoordinateaxis(X,+X,Y,+Y,Zor+Z)isenteredincolumns1718ontheDROPTline.
2.2BASEDRIVENANALYSIS
TheDynamicResponseprogramcanbeusedtodeterminestresses,jointvelocities,jointaccelerationsandjointdisplacementsforbothspectralandtimehistory
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earthquake.
2.2.1SpectralEarthquake
TheDynamicResponseprogramcanbeusedtodetermineresponseduetoaresponsespectrum.Seismicanalysistype,seismicloaddataandanalysisoutputoptionsaredesignatedintheDynamicResponseinputfileinadditiontothebasicanalysisoptions.
AnalysisType
EnterSPECincolumns710ontheDROPTlinetodesignateaspectralearthquakeanalysis.
SeismicLoadData
Forspectralearthquakeanalysis,theseismicloaddataisinputaftertheLOADheaderlineintheformofaresponsespectrumorapowerspectraldensityfunction.TheprogramcontainsanautomatedAPIspectralanalysisfacilitydesignatedbytheSPLAPIlinealongwithageneralresponsespectralanalysisfacilitydesignatedbytheSPLOADline.
Note:EachseismicinputloadrequireseitheraSPLAPIoraSPLOADline.
AutomatedAPISpectralAnalysis
TheautomatedfacilitycontainsAPISoilTypeA,BandCresponsespectrainadditiontosupportinguserdefinednormalizedresponsespectra.EachseismicloadtobedefinedbyoneoftheAPIspectraisinputusingaSPLAPIlineasfollows:
EntertheresponsefactororGfactorwhichdefinestheratioofeffectivehorizontalgroundaccelerationtogravitationalaccelerationincolumns1115.ThesoiltypeortheIDoftheuserdefinedresponsespectrumandtheDirectionalityfactortobeappliedtotheGfactormustbespecifiedfortheX,YandZdirectionsincolumns1636.Themethodusedtocombinemodalresultsisdesignatedincolumns3841.EnterSRSS,PEAK,PRMSorCQCforsquarerootofthesumofthesquares,linearadditionofabsolutevalues,peakplusSRSSorcompletequadraticcombination,respectively.
Note:StructuraldampingonlyisassumedwhenusingtheautomatedAPIspectralanalysis.Also,theIDoftheuserdefinednormalizedresponsespectrummaybeinputinplaceofthesoiltype.
GeneralSpectralResponseAnalysis
ThegeneralspectralanalysiscapabilitiesallowsseismicloadingtobedefinedusingAPIoruserdefinedinputspectrum.APIspectramaybereferencedorresponsespectrumorpowerspectraldensityfunctiondatamaybespecified.RegardlessofwhetherAPIspectraoruserdefineddataisused,generalloadoptionsandloaddatamustbespecifiedontheSPLOADlineasfollows:
SpecifythedampingtypeSDOstructuraldampingonly,FDSequivalentfluiddampingatspecifiedamplitudeorFDAequivalentfluiddampingatactualamplitudeincolumns2123.ForFDSdamping,enterthedampingamplitudeincolumns3944ifdifferentfromthevaluespecifiedontheFDAMPline.
Note:OptionsFDAandFDSrequirethatfluiddampinginputbespecifiedusingtheFDAMPline.
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Themethodusedtocombinemodalresultsisdesignatedincolumns2528.EnterSRSS,PEAK,PRMSorCQCforsquarerootofthesumofthesquares,linearadditionofabsolutevalues,peakplusSRSSorcompletequadraticcombination,respectively.
EntertheresponsefactororGfactorwhichdefinestheratioofeffectivehorizontalgroundaccelerationtogravitationalaccelerationincolumns4550.ThedirectionalityfactortobeappliedtotheGfactormustbespecifiedfortheX,YandZdirectionsincolumns5156,5762and6368,respectively.
APISpectrum
Enterthespectrumsource,eitherAPI,APIA,APIB,orAPICforAPIspectraincolumns912ontheSPLOADline.Leavecolumns1518blank.
UserDefinedSpectra
Userdefineddatamaybespecifiedintheformofanormalizedresponsespectrum,ageneralresponsespectrumorapowerspectraldensityfunction.
NormalizedresponsespectraareusedinconjunctionwiththeSPLAPIlinebyspecifyingtheIDofthespectruminsteadofasoiltypeincolumns22,29or36.
NormalizeduserdefinedresponsespectrumdatamaybeusedtodefineadditionalsoiltypestobeusedinconjunctionwiththeAPIspectralearthquakeoptions.ThespectrumdataisspecifiedusingRSPU1andRSPU2linesimmediatelyfollowingtheSPLAPIline.ThefirstRSPU1linerequiresthenumberofdampingvalues(maximumof3)incolumn10alongwiththeIDofthespectrumincolumn8.ThespectrumdataisenteredontheRSPU2lineandincludesthedampingratioasapercentofcriticaldampingincolumns914,thentheperiodandnormalizedspectrumvalueofeachpointofthespectrumincolumns2180.
Note:UptofifteenspectrumpointsmaybedefinedbyrepeatingtheRSPU2linewiththesamedampingratiospecifiedoneachline.
ThefollowingdescribesanuserdefinedresponsespectrumtobeusedassoiltypeFintheXdirectionwith5percentcriticaldampingandisdefinedby5setsofperiodsandvalues.
ThegeneralresponsespectrumandthepowerspectraldensityfunctionareusedwiththeSPLOADlinebyenteringthespectrumsourceincolumns912ontheSPLOADlineasLINEifthespectrumdataisdefinedonsubsequentinputlines,FILEifthespectrumisdefinedinaexternalfileorPREVifthespectrumistobeusedfromthepreviousseismicloadcase.Enterthespectrumtype,RSPforresponsespectrumorPSDforpowerspectraldensityincolumns1517ontheSPLOADline.AccelerationA,velocityVanddisplacementDspectraaresupported.Specifythespectrumformbyenteringtheappropriateletterincolumn18iftheuserdefined
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dataisintheformofaresponsespectrum.
UserdefinedresponsespectrumdataisspecifiedusingRSPSPClinesimmediatelyfollowingtheSPLOADline.ThefirstRSPSPClinerequiresthenumberofdampingvaluesincolumns710.Enterthenumberofpointsdefinedonthecurveincolumns710onthesecondRSPSPClinealongwiththecriticaldampingforthecurveincolumns1116.Thefirsttwopointsonthecurve,definedbyaperiodandaresponsevalueareenteredincolumns2160.Additionalpointsonthecurvearedefinedinpairsincolumns2160onsubsequentRSPSPClines.
Forexample,thefollowingdescribesanuserdefinedresponsespectrumdefinedby5setsofperiodsandaccelerations(accelerationform)with5percentcriticaldamping.
UserdefinedpowerspectraldensitydataisspecifiedusingPSDSPClinesimmediatelyfollowingtheSPLOADline.ThefirstPSDSPClinerequiresthenumberoffrequencyvaluesincolumns710.Thefirsttwopointsonthecurve,definedbyafrequencyandaspectraldensityvalueareenteredincolumns2160.Additionalpointsonthecurvearedefinedinpairsincolumns2160onsubsequentPSDSPClines.
Forexample,thefollowingdescribesanuserdefinedpowerspectraldensityfunctiondefinedby5setsoffrequenciesandspectraldensityvalues.
OutputOptions
Bydefault,seismicloadcasesarecreatedwhenperformingaspectralearthquakeanalysis.Theprogramalsohastheabilitytooutputloadcombinationsconsistingof
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seismicandstaticresults,equivalentstaticloadsfornonlinearanalysis,responsefunctionsandjointdataincludingdisplacement,velocityandacceleration.
Static+SeismicCombinations
TheDynamicResponsehastheabilitytooptionallycombineseismicresultswithstaticresultsaspartoftheearthquakeanalysis.Whenusingthisfeature,theprogramcreatesfourseismic+staticloadcombinations,twoforelementcheckandtwoforjointcancheck,foreachseismicloadcaseasfollows:
Note:Thisfeaturerequiresthatthestaticsolutionfileexistpriortoexecutionoftheseismicanalysis.Italsoresquiresthatallseismicloadcasesarefullseismicloadcasescontainingtheresponsesforalldirections(i.e.X,YandZresponses).Whenusingseismicloadcasescontainingonlypartoftheseismicresponse,theseloadcasesmustbecombined(usingSRSS)bytheuserpriortomanuallycombiningwithstaticsolutions.
TheseismicandstaticcombinationinformationisinputusingtheSTCMBline.Enterthefactortobeappliedtotheseismicloadswhencombinedwiththestaticloadsforthepurposeofmemberandplateelementcheckincolumns812.Thefactortobeappliedtoseismicloadswhencombinedwithstaticloadsforjointcheckisinputincolumns1317.Entereachofthestaticloadcasestobecombinedwiththeseismicloadcasesandtheloadfactortobeapplied.Sincespectralearthquakeresultsarevalidonlyatthejointsofthestructure,itisrecommendedthattheJOoptionisusedincolumns2728oftheOPTIONSlinewhengeneratingthestaticsolutionfile.
Forexample,105%ofloadcases8and9containedinthestaticsolutionfilearetobecombinedwiththeseismicsolution.Forelementcheckandjointcancheck,seismicstressesaretobefactoredby1.0and2.0,respectively.
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Note:TheSTCMBlineshouldfollowtheSDAMP,FDAMPandMODSELlinesintheinputfile.
EquivalentStaticLoads
EquivalentstaticloadsusedtosimulateearthquakeloadsfornonlinearanalysismaybecreatedusingtheEQKLODline.TheloadcasecanbecreatedtorepresenteithertheactualbaseoractualoverturningmomentbydesignatingSorMincolumn8.
Bydefaultmodalresultsareaddedtogethersuchthatthecorrespondingloadrepresentseitherbaseshearoroverturningmoment.TheloadcasemayalsobegeneratedwiththesignreversedtosimulateloadreversalbyspecifyingRincolumn10.Toobtainoneloadcasecorrespondingtothestandardloadingandanadditionalloadingrepresentingthereversal,enterBincolumn10.Toobtainoneloadcasecorrespondingtoloadingin"all"directions,enterAincolumn10.Inthiscasethenumberofdirectionsmustbespecifiedincolumns1416,withadefaultvalueof20andamaximumof100.
Theloadcasescreatedmaybeappendedtoanexistingmodelorstructuraldatafile.Iftheexistingfilecontainsloadingtobeusedbythesubsequentnonlinearanalysis,theloadcasetoassigntothegeneratedloadsmaybeassignedbydesignatingthenumberofexistingloadcasestoskipincolumns1113.
TheprogramprintstheresponseintheX(0.0degree)andY(90.0degree)directions.WhenthestructureisrespondingprimarilyintheXdirection,theseresponsesdonotoccuratthesametime.Theequivalentstaticloadprocedureassumesthattheprimarystructureresponsemayoccurinanydirectionduringtheearthquakeevent(notonlyalongtheXorYaxes).Theresponseofthestructureisthereforecalculatedfor20directions(every18degrees).Foreachofthesetwentydirections,thebaseshearinthatdirectionandthemomentaboutthatdirectionaredetermined.Equivalentstaticloadsarethengeneratedforthehighestbaseshear.
Aseparateloadcasemaybeoutputforeachmodebyentering'M'incolumn17oftheEQKLODinputline.
TheseismicloadcasescreatedhavetheearthquakeEQSloadingplustheloadcasesspecifiedontheSTCMBlineincludedineachloadcasecreated.TheloadcasesontheSTCMBlinearefactoredbytheappropriateloadfactorindicatedontheSTCMBline.ThejointandmemberloadcasesfactorsontheSTCMBlineareignored.
ResponseFunctions
AfrequencyorperiodresponsefunctionsmaybegeneratedatspecificlocationsonthestructureusingtheRSFUNCline.UptosixfunctionsmaybegeneratedforeachRSFUNClinedesignated.Enterthejointname,thedegreeoffreedomandthedampingtobeusedincolumns716.Additionalfunctionsmaybegeneratedbyspecifyingthejoint,DOFanddampingincolumns1766.Thenumberofpointsusedtodefinethefunctionsisdesignatedincolumns6769whilethefunctiontypeisdesignatedby
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P(period)orF(frequency)incolumn70.Plotsoptionsarespecifiedincolumns7377.
AsmanyRSFUNClinesasrequiredtodesignatethedesirednumberoffunctionsmaybeused.
JointResults
Jointresultssuchasvelocity,accelerationanddisplacementmaybereportedforaparticularseismicloadcasebyenteringV,AorDincolumns2931onthecorrespondingSPLOADline.Resultsmayalsobereportedforallseismicloadcasesbyspecifyingtheprintselectionsincolumns2527ontheDROPTline.
LowLevelEarthquakeAnalysis
LowlevelearthquakeanalysisbasedonAPIWSDorAPILRFDmaybeaccomplishedusingthemethodsfromthepreviousparagraphs.Tospecifylowlevelearthquakeanalysis,theAPIcoderequiresdescriptionofarare,intenseearthquakeforanalysis.Thefollowingsamplespecifiesconditionsforarare,intenseearthquakeandtheproperloadcombinationsforuseinlowseismicactivityzonesperAPI.
TheSTCMBlinespecifiesanelementloadcasefactorof1.0andapunchingshearfactorof.0001.Thiseffectivelyeliminatesseismicloadsfromloadcases3and4generatedbytheSPLAPIline.Loadcase3,whichiseffectivelyadeadloadcase,willbeusedsubsequentlyinjointcanlowlevelearthquakeanalysis.SeeJointCanmanualforimplementationoflowlevelearthquakeanalysisinjointstrengthcheck.
CombiningwithStaticResults
Theprogramcreatesacommonsolutionfilecontainingendforces,stresses,reactionsanddisplacementsforeachseismicloadsetspecifiedintheDynamicResponseinputfile.BecausetheseresultsareobtainedbycombiningmodalresultsusingRMStechniques,endforces,stresses,etc.havenosignassociatedandaretakenasall
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positivevalues.Therefore,whenmanuallycombiningspectralearthquakeresultswithstaticresults,thePRSTandPRSCcombineoptionsmustbeused.
2.2.2TimeHistoryEarthquake
TheDynamicResponseprogramcanbeusedtodetermineresponseduetoabasedriventimehistory.Uptothreeseparatetimehistoriesmaybeusedforanyanalysis.Analysistype,seismicloaddataandanalysisoutputoptionsaredesignatedintheDynamicResponseinputfileinadditiontothebasicanalysisoptions.
AnalysisType
EnterTIMEincolumns710ontheDROPTlinetodesignateatimehistoryearthquakeanalysis.
LoadOptions
Fortimehistoryearthquakeanalysis,inputloadingandloadoptionsareinputaftertheLOADheaderlineusingtheTHLOAD,THFACT,TIMEandTHBEGINinputlines.
Note:Eachtimehistoryloadisdefinedbyusingaseparatesetoftheselines.
DampingMethod
GeneraltimehistoryoptionsaredesignatedontheTHLOADlineimmediatelyfollowingtheLOADheader.SpecifythedampingtypeSDOstructuraldampingonly,LFDlinearizedfluiddampingorNFDfornonlinearfluiddampingincolumns1820.
Note:Fornonlinearfluiddamping,thefluidforcesarecalculatedateverytimestepduringtheintegration.ThisoptionrequirestheprogramcalculatedfluiddampingoptionPContheFDAMPline.
Forlinearizedfluiddamping,thedampingamplitudeusedtocalculatetheequivalentlinearfluiddampingmaybeoverriddenbyspecifyingavalueincolumns2128.
InterpolationScheme
Themethodusedtointerpolatebetweentimehistoryinputvaluesisdesignatedincolumns2930.EnterLN,QDorCUforlinear,quadraticorcubicinterpolation,respectively.
DirectionalityFactors
ThedirectionalityfactortobeappliedtothetimehistoryvalueisspecifiedfortheX,YandZdirectionsincolumns1115,1620and2125oftheTHFACTline,respectively.Ifmorethanonetimehistoryistobeused,thedirectionalityfactorsforeachtimehistorymustbespecifiedincolumns2655.
IntegrationParameters
IntegrationparametersarestipulatedontheTIMEline.Enterthestartforthebeginningofthetimehistoryintegrationincolumns1120.Iftheanalysisistoterminatebeforetheendofthetimehistoryinput,entertheendtimeincolumns2130.Theoutputtimeinterval,minimumintegrationstepandthetolerancefactoraredesignatedincolumns3140,4150and5160,respectively.
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Forexample,thefollowingdescribesantimehistoryfunctionspecifiedintheinputfile.StructuraldampingonlyisusedinconjunctionwithlinearinterpolationasdesignatedontheTHLOADline.Onetimehistoryfunctionisusedwithdirectionalityfactorsof1.0,1.0and0.5appliedtoitfortheX,YandZdirections,respectively.Thestarttimeis0secondsandendtime25seconds.Outputisrequestedatevery0.25seconds.
TimeHistoryInput
TimehistorydatamaybespecifiedintheDynamicresponsefileormaybereadfromanexternaldatafile.Thesourceofthetimehistorydataisdesignatedincolumns912ontheTHLOADline.EnterLINEifthetimehistorydataisdefinedonsubsequentinputlines,FILEifthedataisdefinedinaexternalfileorPREVifthetimehistorydataistobeusedfromthepreviousseismicloadcase.
InputParameters
SpecifyingdataintheinputfilerequiresthatoverallparametersbespecifiedontheTHBEGINline.Upto3separatetimehistoriesmaybedefinedforaparticularinputload.Enterthenumberoftimehistoriestobedefinedinthefileincolumns810andthenameidentifyingthetimehistoryincolumns2225.Thetype,eitheracceleration,velocity,displacementorgravityaccelerationisdesignatedbyA,V,DorGincolumn30,respectively.
TimeHistoryLoadData
Thetimehistorydatamaybeenteredinstandardformat,compressedformatorviaanexternalinputfile.
StandardFormat
SpecifySTDincolumns1420ontheTHBEGINlineforstandardinputformat.
TimehistoryloaddataisspecifiedusingaTHDATAlineforeachtimepoint.Foranytimepoint,enterthetimeincolumns1120andthevalueincolumns2130.Ifmorethanonetimehistoryistobedefined,enterthevalueforthesecondfunctioncorrespondingtothistimeincolumn3140.Thevalueforthethirdfunctionisinputincolumns4150.Thefollowingillustratesoneaccelerationtimehistoryinputusingstandardformat.
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Note:Thefirsttimepointofthetimehistoryfunctionisassumedtobezero.Thefirsttimepointenteredbytheusermustbegreaterthanzero.ThetimehistoryisterminatedbyusingaTHDATAlinewithallfieldleftblank.
CompressedFormat
ThetimehistorydatamaybeenteredincompressedformatbyspecifyingCMPincolumns1420ontheTHBEGINline.
TimehistoryloaddataisspecifiedusingaTHCOMPlineforeachtimepoint.Compresseddataisassumedtobespecifiedwiththeconstanttimeintervalspecifiedincolumns1420ontheTHBEGINline.Enterthetimehistoryvalueincolumns1170.TheTHCOMPlinewithENDdesignatedincolumns810signifiestheendoftheinputdata.
Thefollowingillustratesoneaccelerationtimehistoryinputusingcompressedformat.Theconstanttimeintervalis0.25secondsasdesignatedontheTHBEGINline.
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ExternalFileInput
Whenspecifyingtimehistoryloaddatafortimehistoryearthquake,datawhichwouldnormallybespecifiedusingTHDATAlinesisinputinanexternalinputfilewithoutdatalabels.Theexternalfilebeginswithasinglerecord.ThisrecordbeginswithafourcharacternameasspecifiedontheTHLOADdatarecord.Thenextfourcolumns,columns58,specifythenumberoftimehistoryfunctionsasspecifiedincolumns810oftheTHBEGINdatarecord.Thetype,eitheracceleration,velocity,displacementorgravityaccelerationisdesignatedbyA,V,DorGincolumn9,respectively.Theinputunitsinches,feet,centimeters,millimetersandmetersareinputbyspecifying'IN','FT','CM','MM'and'ME'incolumns1213respectively.
ThefollowingrecordsaretheequivalentofTHDATArecordsinstandardformat,butareinputwithspecificfieldwidthsandnodatalabels.Columns112specifythetimepointthisisequivalenttocolumns1120oftheTHDATArecord.Columns1324,2536and3748consistofthetimehistoryvaluesforthefirst,secondandthirdfunction,respectively.Thenumberoftimehistoryfunctionvaluesspecifiedmustcorrespondtothevalueincolumns58ofthefirstrecord.Subsequentrecordsspecifyothertimehistorypoints.Alltimehistorypointsspecifiedmusthavetimepointsgreaterthanzero.Thefinalrecordhasatimepointof0.0.
Thefollowingisanexampleofexternalfileinput.Inorderforthisfiletobeused,thedynamicresponseinputfilemusthaveaTHLOADrecordwithtimehistoryinputsourcefield(columns912)ofMXCT.Theinputspecifiesthreetimehistoryfunctionvaluesarespecifiedintheforthcomingrecords.Theinputtimevaluesof0.00,0.02,0.04,0.06,0.08and0.10aredatainthefirsttwelvecolumnsthethreetimehistoryfunctionvaluesarespecifiedincolumns1324,2536and3748.Typicaldatainputwouldconsistofmanymorerecords.Thelastdatarecordhasatimepointof0.0.
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OutputOptions
Thetimehistoryearthquakeanalysiscreatesloadcases,printsandplotsmodalresponses,baseshearandoverturningmomentinadditiontojointaccelerations,velocitiesanddisplacements.Analysisoutputoptionsaredesignatedintheoutputoptionsfieldsincolumns3359ontheTHLOADline.
LoadCaseCreation
TheDynamicResponseprogramhastheabilitytocreatealoadcasecorrespondingtothetimepointhavingmaximumoverturningmomentand/ormaximumbaseshearbyspecifyingMXMorMXSintheoutputoptionsfieldsontheTHLOADline,respectively.EnterALLifloadcasesaretobecreatedatforalltimepoints.
ModalResponseData
Modalresponsesversustimemaybeprintedand/orplottedbyspecifyingPRTandPLT,respectively,intheoutputoptionsfieldsontheTHLOADline.
BaseShearandOverturningMomentPlots
BaseshearandoverturningmomentplotsmaybegeneratedbyenteringPLMandPLSinoneoftheoutputoptionfieldslocatedontheTHLOADline.
JointResults
Jointresultsincludingacceleration,velocityanddisplacementmaybeplottedandlistedforuptosixteenjoints.JointplotoptionsarespecifiedintheoutputoptionsfieldsontheTHLOADline.
Jointaccelerationoptionsinclude:
JMAPrintsmaximumandminimumvaluesforjointaccelerationforeachdirection.
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JPASameasJMAplusplotsaccelerationtimehistory
JTASameasJPAplusprintsaccelerationtimehistorydata
Note:Jointaccelerationoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Jointvelocityoptionsinclude:
JMVPrintsmaximumandminimumvaluesforjointvelocityforeachdirection.
JPVSameasJMVplusplotsvelocitytimehistory
JTVSameasJPVplusprintsvelocitytimehistorydata
Note:Jointvelocityoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Jointdisplacementoptionsinclude:
JMDPrintsmaximumandminimumvaluesforjointdisplacementforeachdirection.
JPDSameasJMDplusplotsdisplacementtimehistory
JTDSameasJPDplusprintsdisplacementtimehistorydata
Note:Jointdisplacementoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Anynumberofjointsmaybedesignatedforplotsandreports.JointstobeoutputarespecifiedusingJTNUMlinesimmediatelyfollowingtheTHLOADline.
Thefollowinginputillustratessomeoftheoutputoptions.Twoloadcases,onecorrespondingtothetimeofmaximumbaseshearandonecorrespondingtothetimeofmaximumoverturningmoment,arecreated.Baseandoverturningmomenttimehistoriesaretobeplottedinadditiontojointaccelerationanddisplacementplotsforjoints601,603,605and607.
2.3FORCEDRIVENANALYSIS
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TheDynamicResponseprogramcanbeusedtodeterminestresses,jointvelocities,jointaccelerationsandjointdisplacementsforstructuressubjectedtoperiodicforces,forcetimehistoryorengine/compressorvibration.
Forperiodic,timehistoryorengine/compressorvibrationanalysis,theanalysistype,loaddataandanalysisoutputoptionsaredesignatedintheDynamicReponseinputfileinadditiontothebasicanalysisoptions.
2.3.1ForceTimeHistory
AnalysisType
TheanalysislabelVIBRmustbeenteredincolumns710ontheDROPTlineforanyforcedresponseanalysis.Forforcetimehistoryanalysis,enterTHISincolumns710ontheFVIBline.
LoadOptions
LoadoptionsandinputloadingisspecifiedfollowingtheLOADheaderlineusingtheFVIB,TIME,THFORCEandLOADlines.BasicloadoptionsaredesignatedontheFVIBlinewhileintegrationparametersarespecifiedontheTIMEline.
Note:EachtimehistoryloadrequiresaseparatesetofFVIB,TIME,THFORCEandLOADlines.
DampingMethod
SpecifythedampingtypeSDOstructuraldampingonly,LFDlinearizedfluiddampingorNFDfornonlinearfluiddampingincolumns1719oftheFVIBline.
Note:Fornonlinearfluiddamping,thefluidforcesarecalculatedateverytimestepduringtheintegration.ThisoptionrequirestheprogramcalculatedfluiddampingoptionPContheFDAMPline.
Forlinearizedfluiddamping,thedampingamplitudeusedtocalculatetheequivalentlinearfluiddampingmaybeoverriddenbyspecifyingavalueincolumns2027.
InterpolationScheme
Themethodusedtointerpolatebetweeninputvaluesisdesignatedincolumns2839ontheFVIBline.EnterLNforlinear,QDforquadraticorCUforcubic.
Note:Ingeneral,linearinterpolationisapplicableforstep,ramporspikefunctions.Thequadraticandcubicinterpolationmethodssmoothsouttheinputfunction.
Forexample,thefollowingdescribesantimehistoryfunctionspecifiedintheinputfile.StructuraldampingonlyisusedinconjunctionwithlinearinterpolationoftheforcetimehistoryinputasdesignatedontheFVIBline.
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IntegrationParameters
IntegrationparametersarestipulatedontheTIMEline.Enterthestartforthebeginningofthetimehistoryintegrationincolumns1120.Iftheanalysisistoterminatebeforetheendofthetimehistoryinput,entertheendtimeincolumns2130.Theoutputtimeinterval,minimumintegrationstepandthetolerancefactoraredesignatedincolumns3140,4150and5160,respectively.
Forexample,thefollowingdescribesantimehistoryfunctionspecifiedintheinputfile.StructuraldampingonlyisusedinconjunctionwithlinearinterpolationasdesignatedontheFVIBline.Thestarttimeis0secondsandendtime25seconds.Outputisrequestedatevery0.25seconds.
TimeHistoryInput
TimehistoryinputdatamaybespecifiedintheDynamicresponsefileormaybereadfromanexternaldatafile.Thesourceofthetimehistorydataisdesignatedincolumns912ontheFVIBline.EnterLINEifthedataisdefinedonsubsequentinputlines,FILEifthetimehistoryisdefinedinaexternalfileorPREVifthedataistobeusedfromthepreviousloadcase.
InputParameters
Whenspecifyingforcetimehistorydataintheinputfile,timehistoryinputparametersmustbespecifiedontheTHFORCEline.Enterthetotalnumberofjointsthatforceisappliedincolumns810.Timehistorydatamaybeinputusingauniformtimeintervalbetweenpointsormaybespecifiedforvarioustimepointsspacednonuniformly.Theinputformat,eitheruniformornonuniformmustbedesignatedbyUNIorNONincolumns1113respectively.Foruniforminput,specifythetimeintervalincolumns1420.Thetimehistorynameisinputincolumns2225.ThefollowingillustratestheinputrequiredforthenonuniformtimehistoryinputnamedTESTappliedatonejoint.
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TimeHistoryData
ThetimehistoryinputdataisspecifiedusingLOADlineslocatedaftertheTHFORCEline.Enterthejointtowhichtheloadisappliedincolumns811.Thetimethattheloadistobeappliedisenteredincolumns1216.IfseveraltimesarespecifiedinconsecutiveLOADlines,thetimesmustbeinascendingorder.Theforcesandmomentsactingonthejointatthespecifiedtimearedesignatedincolumns1759.
Forexample,aloadof10.0isappliedintheglobalXdirectiontojoint107attime1.0seconds.Theloadremainsconstantfor0.25secondsafterwhichitisremoved.
Note:Noticethatthethirdtimepointisdefinedat1.001secondsinsteadof1.00secondssothattheforceisappliedoverasmalltimeperiodratherthanappliedinstantaneously.
ScalingLoadData
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Loaddatamaybefactoredbyspecifyingaloadfactorincolumns5965ontheFVIBline.
LoadCaseTimeHistoryData
TimehistoryinputdatamayalsobespecifiedusingLOADClines.TheselinesarelocatedaftertheTHFORCEline.Inthiscase,ratherthanspecifyingjointsatwhichtheloadappliesandsupplyingatimehistory,theloadsfromtheSACSIVloadcasespecifiedincolumns811ontheLOADClinewillbeappliedatthetimespecifiedincolumns1216.IfseveraltimesarespecifiedinconsecutiveLOADClines,thetimesmustbeinascendingorder.Thescalingfactortobeappliedtotheloadsisspecifiedincolumns1723.Thismethodisveryusefulforapplyingsimilartimevaryingloadstomanypositions,asinblastloading.Noticealsothatthisloadingisnotlimitedtojointloadsonlydistributedandpressureloadsmaybeappliedinthismanneraswell.
Forexample,loadcaseB01isappliedwithascalingfactorof0.0attime1.0seconds,afactorof1.0attime1.001seconds,afactorof1.0attime1.25seconds,afactorof0.0attime1.251secondsandafactorof0.0attime10.0seconds.IfloadcaseB01specifiedaloadatjoint107of10.0intheglobalXdirection,thenthisexamplewouldresultinthesameloadingatjoint107asthepreviousLOADexample.
TimeHistoryCollapseAnalysis
IncrementalloadsforforcetimehistoryCollapseanalysiscanbegeneratedbyspecifyingTCLPincolumns710ontheDROPTinputline.Also,incrementalloadsfromadynamicshipimpactCollapseanalysiscanbegeneratedbyspecifying'SHIP'incolumns710ontheDROPTlinetogetherwith'CLP'incolumns3335ontheTHLOADinputline.Alternatively,equivalentstaticloadscanbegeneratedbyspecifying'ESL'incolumns3335ontheTHLOADinputline.
TheexamplebelowreferstoadynamicshipimpactanalysiswithincrementalloadsbeinggeneratedforasubsequentCollapseanalysis.Theweight,speedanddirectionofimpactisdefinedontheSHIPinputlinetogetherwithimpactedjointname.
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OutputOptions
Theforcetimehistoryanalysiscreatesloadcases,printsandplotsmodalresponses,baseshearandoverturningmomentinadditiontojointaccelerations,velocitiesanddisplacements.Analysisoutputoptionsaredesignatedintheoutputoptionsfieldsincolumns3258ontheFVIBline.
LoadCaseCreation
Loadcasescorrespondingtoeachtimepointorthecriticaltimepointsmaybegeneratedbytheforcedresponseanalysis.Loadcasescorrespondingtothetimepointhavingmaximumoverturningmoment,maximumbaseshearorbothbyspecifyingMXM,MXSorMMSintheoutputoptionsfieldsontheFVIBline,respectively,maybecreated.EnterALLtohavealoadcasecreatedateachtimepointoftheanalysis.
Note:Loadoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybedesignated.
ModalResponseData
Modalresponsesversustimemaybeprintedand/orplottedbyspecifyingPRTandPLT,respectively,intheoutputoptionsfieldsontheFVIBline.EnterPPTtohavemodalresponsesprintedandplotted.
Note:Modalresponseoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybedesignated.
BaseShearandOverturningMomentPlots
BaseshearandoverturningmomentplotsmaybegeneratedbyenteringPLMandPLS,respectively,inoneoftheoutputoptionfieldslocatedontheFVIBline.
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JointResults
Jointresultsincludingacceleration,velocityanddisplacementmaybeplottedandlistedforuptosixteenjoints.JointplotoptionsarespecifiedintheoutputoptionsfieldsontheFVIBline.
Jointaccelerationoptionsinclude:
JMAPrintsmaximumandminimumvaluesforjointaccelerationforeachdirection.
JPASameasJMAplusplotsaccelerationtimehistory
JTASameasJPAplusprintsaccelerationtimehistorydata
Note:Jointaccelerationoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Jointvelocityoptionsinclude:
JMVPrintsmaximumandminimumvaluesforjointvelocityforeachdirection.
JPVSameasJMVplusplotsvelocitytimehistory
JTVSameasJPVplusprintsvelocitytimehistorydata
Note:Jointvelocityoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Jointdisplacementoptionsinclude:
JMDPrintsmaximumandminimumvaluesforjointdisplacementforeachdirection.
JPDSameasJMDplusplotsdisplacementtimehistory
JTDSameasJPDplusprintsdisplacementtimehistorydata
Note:Jointdisplacementoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Uptosixteenjointsmaybedesignatedforplotsandreports.JointstobeoutputarespecifiedusingtheJTNUMlineimmediatelyfollowingtheTHLOADline.
Thefollowinginputillustratessomeoftheoutputoptions.Twoloadcases,onecorrespondingtothetimeofmaximumbaseshearandonecorrespondingtothetimeofmaximumoverturningmoment,arecreated.Baseandoverturningmomenttimehistoriesaretobeplottedinadditiontojointaccelerationanddisplacementplotsforjoints601,603,605and607.
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2.3.2PeriodicVibration
AnalysisType
TheanalysislabelVIBRmustbeenteredincolumns710ontheDROPTlineforanyforcedresponseanalysis.Forperiodicvibrationanalysis,enterPERIincolumns710ontheFVIBline.
LoadOptions
PeriodicloadingandoptionsforthatloadingisdefinedusingtheFVIBandLOADinputlinesspecifiedaftertheLOADheaderline.GeneralloadoptionsarespecifiedontheFVIBline.
Note:EachperiodicloadingdefinedrequiresaseparatesetofFVIBandLOADinputlines.
DampingMethod
SpecifythedampingtypeSDOstructuraldampingonly,LFDlinearizedfluiddampingorNFDfornonlinearfluiddampingincolumns1719ontheFVIBline.
Note:Fornonlinearfluiddamping,thefluidforcesarecalculatedateverytimestepduringtheintegration.ThisoptionrequirestheprogramcalculatedfluiddampingoptionPContheFDAMPline.
Forlinearizedfluiddamping,thedampingamplitudeusedtocalculatetheequivalentlinearfluiddampingmaybeoverriddenbyspecifyingavalueincolumns2027.
TimeParameters
Forperiodicvibrationthetimespanthatthevibrationistobemonitoredisinputincolumns7277ontheFVIBline.Ingeneralthistimespanistheshortesttimethatthevibrationisrepeatable.Thenumberoftimepointsthatthetimespanistobedividedisspecifiedincolumns7880.
Note:Thenumberoftimepointsshouldbesufficienttopickupthehighestfrequencyofinterest.
Forexample,thefollowingdescribesanperiodicfunctionspecifiedintheinputfile.Structuraldampingonlyisusedinconjunctionwithquadraticinterpolationoftheperiodicinput.Theanalysistimespanis1.0secondandtheanalysisistobebrokenupinto50timepoints.
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PeriodicInput
PeriodicloaddatamustbespecifiedintheDynamicResponseinputfileusingLOADlineslocatedaftertheFVIBline.Inputloaddatamaybescaledautomaticallybyenteringaloadscalingfactor.
PeriodicLoadData
Enterthejointtowhichtheloadisappliedincolumns811.Theforcesandmomentsactingonthejointaredesignatedincolumns1759.
Entertheperiodthatthesetofforcesisactingincolumns6974alongwiththephaseangleincolumns7580.
Note:ForcesareappliedasF*cos(2pT/(T+a))whereTistheperiodandaisthephaseangle.
Forexample,aperiodicforceof10.0isappliedintheglobalXdirectiontojoint107.Theperiodis0.20secondsandthephaseangleis90degrees.
ScalingLoadData
Loaddatamaybefactoredbyspecifyingaloadfactorincolumns5965ontheFVIBline.
OutputOptions
Theperiodicvibrationanalysiscreatesloadcases,printsandplotsmodalresponses,baseshearandoverturningmomentinadditiontodeterminingmaximumabsolutedisplacements.Analysisoutputoptionsaredesignatedintheoutputoptionsfieldsincolumns3258ontheFVIBline.
LoadCaseCreation
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Loadcasescorrespondingtoeachtimepointorthecriticaltimepointsmaybegeneratedbytheperiodicvibrationanalysis.Loadcasescorrespondingtothetimepointhavingmaximumoverturningmoment,maximumbaseshearorbothbyspecifyingMXM,MXSorMMSintheoutputoptionsfieldsontheFVIBline,respectively,maybecreated.EnterALLtohavealoadcasecreatedateachtimepointoftheanalysis.
Note:Theaboveloadoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybedesignated.
Theprogramalsohastheabilitytocreatealoadcasecorrespondingtothetimeofmaximumdisplacementorrotationforaparticularjoint.Enterthejointnameincolumns6669andthedegreeoffreedomtomonitorincolumns7071ontheFVIBline.
Note:Whencreatingaloadcaseforamaximumjointdisplacementorrotation,nootherloadcasesarecreated.Therefore,theMXM,MXSandMMSmaynotbeusedwhenusingthisfeature.
ModalResponseData
Modalresponsesversustimemaybeprintedand/orplottedbyspecifyingPRTandPLT,respectively,intheoutputoptionsfieldsontheFVIBline.EnterPPTtohavemodalresponsesprintedandplotted.
Note:Modalresponseoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybedesignated.
BaseShearandOverturningMomentPlots
BaseshearandoverturningmomentplotsmaybegeneratedbyenteringPLMandPLSinoneoftheoutputoptionfieldslocatedontheFVIBline.
JointDisplacements
Jointmaximumdisplacementresultsmaybeprintedusingoneofthefollowingoptions:
MXDprintsmax.X,YandZdisplacementofeachjointinthestructure
SMDselectsmax.displacementforallperiodicloadcasesforeachjoint.
DSMprintsmax.absolutesumofX,YandZdisplacementforeachperiodicloadcasetoproduceamaximumpossibledisplacement.
Note:Jointdisplacementoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Thefollowinginputillustratessomeoftheoutputoptions.Twoloadcases,onecorrespondingtothetimeofmaximumbaseshearandonecorrespondingtothetimeofmaximumoverturningmoment,arecreated.BaseandoverturningmomenttimehistoriesaretobeplottedinadditiontoreportingthemaximumX,YandZjointdisplacements.
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2.3.3Engine/CompressorVibration
Theengineorcompressorvibrationanalysisdeterminesjointdisplacementduetounbalancedforces.Jointdisplacementscanbecomparedversusvariousallowabledeflectionspecificationsandexpressedasdisplacementunitycheckratios.
AnalysisType
TheanalysislabelENGVmustbeenteredincolumns710ontheDROPTlineforengineorcompressorvibrationanalysis.
LoadOptions
Engineunbalancedloadingisenteredintheformofmechanicalunbalancedforces,gastorquesorgeneralunbalancedforces.LoadingandloadoptionsaredefinedusingtheENGVIB,RSPEEDandUNBALlinesfollowingtheLOADheaderline.
Note:EachsetofloadingrequiresaseparatesetofRSPEEDandUNBALlines.
DampingMethod
OnlystructuraldampinginputontheSDAMPlineisconsideredforenginevibrationanalyis.
Note:Becausefluiddampingisnotsupported,theFDAMPlineshouldnotbeusedforenginevibration.
EngineSpeedParameters
EnginespeedparametersaredesignatedontheENGVIBline.Thebeginningspeed(thelowestspeed)andtheendingspeed(thehighestspeed)arespecifiedincolumns713and1420,respectively.
Therunningspeedrangeisdefinedbythebeginningandendingspeeds.Theprogramdividesthespeedrangeintoincrementsforthepurposeoftheanalysisusingeitherconstantincrementsorvaryingincrementsbasedonmodalfrequencies.Specifyoneofthefollowingincrementationmethodsincolumns2123:
CONConstantincrementation
MODIncrementsvariedsoeachmodalfrequencyisincludedasananlaysisspeed
MAHSameasMODexceptthateachharmonicfrequencyisalsoincluded
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USRAnalysisspeedsdefinedbytheuserusingUSRSPlines
Forconstantincrements,thespeedincrementvalueenteredincolumns2428isthetotalnumberofspeedpointstoanalyze.Forvaryingincrementsontheotherhand,thevalueenteredinthesecolumnsisusedtodeterminethesmallestspeedincrementallowedbetweenmodes.
Thefollowingshowstheinputforabeginspeedof100rpmandendingspeedof500rpmusingconstantspeedincrements.
UserdefinedrunningspeedsarespecifiedusingtheUSRspeedoptionontheENGVIBlineandUSRSPlinesimmediatelyfollowingtheENGVIBline.Forexample,thefollowinginputdesignatesanalysisrunningspeedsof120,150,200,300,and400rpm.
NonlinearInterpolationPower
Bydefault,2.0isusedasthenonlinearinterpolationpower.Enterthenonlinearinterpolationpoweroverridetobeusedforanymechanicalunbalancedforcesinterpolatednonlinearlybetweenrunningspeedsincolumns2933.Iftheinterpolationpowerisp,thentheinterpolationisaccomplishedasfollows:
whereFaretheforcesandaretherunningspeeds.Thisfieldmaybeleftblankiflinearinterpolationisusedforallunbalancedforces.
CalculationPointsperCycle
Bydefault,10pointsarecalculatedforthehighestharmonicdetermined.Thisvaluemaybeoverriddenbyspecifyingthemaximumnumberofpointscalculatedforthe
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highestharmonicincolumns3739ontheENGVIBline.
Twentypointsarecalculatedforonecycleofthefundamentalfrequencybydefault.Entertheminimumnumberofpointstobecalculatedpercycleincolumns3436ifthisvalueistobeoverridden.
Note:Ifharmonicsareencountered,thenumberofpointscalculatedpercycleisthemaximumofthenumberofpointsperfundamentalandthenumberofpointscalculatedperharmonic.
AllowableOption
Thedeflectionsdeterminedbytheprogramcanbecomparedtopublishedallowabledeflectionsandexpressedasdisplacementunitycheckratios.Theallowableoptionisspecifiedincolumns4041asfollows:
DLDLineAllowable
SNSNAME
MLUSMilitarySpecification
VEMaximumVelocity
ThefollowingillustratestheinputrequiredfordisplacementunitycheckratiostobedeterminedusingtheDLineallowables.
IftheallowableoptionisVE(maximumvelocity),themaximumvelocityallowedisenteredincolumns4246.
JointSelection
Bydefault,alljointsaremonitoredintheenginevibrationanalysis.JointsmaybeoptionallyselectedtobeincludedusingtheJNTSELline.Forexample,thefollowingdesignatesthatonlyjoints101,103,105,107,109and111aretobemonitoredintheanalysis.
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Note:AsmanyJNTSELlinesasrequiredmaybeused.IfJNTSELlinesarespecified,onlyjointsspecifiedaremonitoredduringtheanalysis.
UnbalancedForceInput
Engineunbalancedforcesmaybeexpressedintermsofgastorques,mechanicalunbalancedforcesand/orgeneralunbalancedperiodicforcesatvariousrunningspeeds.
Foraparticularrunningspeed,unbalancedforcescanbeinputasseparateloadconditionswheremaximumresponsefromeachisaddedand/ormaybespecifiedinthesameloadconditionifphaseanglesbetweenunbalancedforcesisknown.
EachloadconditionthatunbalancedforcesaretobedefinedisdesignatedbyaRSPEEDlinewiththerunningspeeddesignatedincolumns915.
GasTorqueLoading
Unbalancedforcesduetogastorquemaybeexpressedasmaximumgastorqueatvariousharmonicsorintheformofatotalgastorquecurve.
Whenunbalancedforcesduetogastorqueareknownforvariousharmonics,loadingisspecifiedintheformofaperiodicloadingusingUNBALlinesspecifiedimmediatelyaftertheRSPEEDline.
Thejointtowhichtheloadisappliedisdesignatedincolumns811.TheforcetypeSINisusedforloaddescribedbyasinglesinewave(amplitudeandphaseangle)andmustbedesignatedincolumns1214.Theforcesactingonthejointaredesignatedincolumns1758.
Enterthephaseangleincolumns5965,theinterpolationtype,eitherLNorNL,incolumns6667andtheharmonicnumberincolumns6869.
Theprogramallowsloadingtobegroupedandconsiderseachloadgrouptoactindependently.Themaximumdisplacementsresultingfromeachloadgrouparesummedtogethertodeterminethetotaldisplacement.Theloadgrouptowhichthisforceisassignedisstipulatedincolumns7071.
Forexample,agastorqueabouttheglobalXaxisatjoint107isknownforthefirst3harmonicsatarunningspeedof300rpm.Sincephasingisknown,eachvalueistobeassignedtothesameloadgroup,loadgroup1.Linearinterpolationistobeusedbetweenrunningspeeds.
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AtotalgastorquecurvemaybeinputasaseriesofequallyspacedpointsintimeusinganUNBALlineandLDFACTlinesimmediatelyaftertheRSPEEDline.
Thejointtowhichtheloadisappliedisdesignatedincolumns811.TheforceoptionTIM,designatingforceinputbyaseriesofequallyspacedtimepoints,mustbedesignatedincolumns1214.Theappliedforcesactingonthejointaredesignatedincolumns1758.
Entertheinterpolationtype,eitherLNorNL,incolumns6667andthehighestharmonicnumbertobeusedfromtheFourierseriesincolumns7273.Theloadgrouptowhichthisforceisassignedisstipulatedincolumns7071.
Note:TheharmonicnumberandphaseanglefieldsmustbeleftblankwheninputtingloaddescribedbyequallyspacedtimepointsasdesignatedbytheTIMforceoption.
ThefollowingexampleshowsatotalgastorquecurveformomentabouttheglobalXaxisatjoint107definedat300rpm.Thecurvewillbedefinedat18degreeincrements(20points).Eachvalueonthecurveistobeassignedtothesameloadgroup,loadgroup1.Linearinterpolationistobeusedbetweenrunningspeedsandthehighestharmonicnumbertobeusedis10.
MechanicalUnbalancedForces
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MechanicalunbalancedforcesarespecifiedintheformofaperiodicloadingusingUNBALlinesspecifiedimmediatelyaftertheRSPEEDline.
Thejointtowhichtheforcesareappliedisdesignatedincolumns811.TheforcetypeSINisusedforloaddescribedbyasinglesinewave(amplitudeandphaseangle)andmustbedesignatedincolumns1214.Theforcesactingonthejointaredesignatedincolumns1758.
Enterthephaseangleincolumns5965,theinterpolationtype,eitherLNorNL,incolumns6667andtheharmonicnumberincolumns6869.
Theprogramallowsloadingtobegroupedandconsiderseachloadgrouptoactindependently.Themaximumdisplacementsresultingfromeachloadgrouparesummedtogethertodeterminethetotaldisplacement.Theloadgrouptowhichthisforceisassignedisstipulatedincolumns7071.
Forexample,acompressorhasprimaryandsecondarymechanicalunbalancedforcesthatcreatemomentsabouttheglobalYandZaxeswhicharephased90degreesapart.At300rpms,theprimaryandsecondaryunbalancedforcescreate16000inkipand2600inkipmomentsabouttheYaxisand2400inkipand750inkipmomentsabouttheZaxisrespectively,appliedatjoint107.Becausetheunbalancedforcesareassumedtovarywiththesquareoftherunningspeed,nonlinearinterpolationwithapowerof2istobeused.
GeneralUnbalancedPeriodicForces
Generalunbalancedforcesmaybeinputintheformoftimehistoryorperiodicloading.
Whenunbalancedforcesareknownforvariousharmonics,loadingisspecifiedintheformsinewavesofaknownamplitudeandphaseangleusingUNBALlinesspecifiedimmediatelyaftertheRSPEEDline.UnbalancedforcesmayalsobeinputintheformofatimehistorywithequallyspacedtimepointsusinganUNBALlineandLDFACTlines.
Ineithercase,thejointtowhichtheloadisappliedisdesignatedincolumns811.Theforcetype,eitherSINforsinglesinewaveorTIMfortimehistory,mustbedesignatedincolumns1214.Theforcesactingonthejointaredesignatedincolumns1758.
Singlesinewavetypeloadingrequiresthephaseangleincolumns5965andtheharmonicnumberincolumns6869whilethetimehistorytyperequiresonlythehighestharmonictobeusedfromtheFourierseriesincolumns7273.
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Theinterpolationtype,eitherLNorNL,mustbedesignatedincolumns6667.Theloadgrouptowhichthisforceisassignedisstipulatedincolumns7071.
Note:Theprogramallowsloadingtobegroupedandconsiderseachloadgrouptoactindependently.Themaximumdisplacementsresultingfromeachloadgrouparesummedtogethertodeterminethetotaldisplacement.
ThefollowingillustratesanunbalancedforcealongtheglobalZandabouttheglobalXaxisatjoint107.Theforceisknownforthefirst3harmonicsatarunningspeedof300rpmandeachvalueistobeassignedtothesameloadgroup,loadgroup1.Linearinterpolationistobeusedbetweenrunningspeeds.
ThefollowingexampleshowsaforcetimehistoryinputformomentabouttheglobalXaxisatjoint107definedat300rpm.Thecurvewillbedefinedat18degreeincrements(20points).Eachvalueonthecurveistobeassignedtothesameloadgroup,loadgroup1.Linearinterpolationistobeusedbetweenrunningspeedsandthehighestharmonicnumbertobeusedis10.
OutputOptions
Theenginevibrationanalysiscalculatesgeneralizedforcesandjointdisplacementsforthevariousconditionsdefined.Jointdisplacementsmaybecomparedtoallowabledisplacementcurvesandexpressedintermsofadisplacementunitycheckratio.
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GeneralizedForces
Generalizedforceprintoptionsaredesignatedincolumns5354ontheENGVIBline.EnterPTforthestandardgeneralizedforceprintorFLforafullprint.
JointResults
JointresultsforalljointsthatexceedtheallowabledisplacementatanyrunningspeedmaybeprintedbyspecifyingPTincolumns5758ontheENGVIBline.
JointdisplacementsmayalsobeplottedbyspecifyingPLincolumns5556.Bedefault,alljointsareplottedwhenthejointplotfeatureisinstigated.JointstobeplottedmaybedesignatedusingtheJNTPLTlinefollowingtheENGVIBline.
Forexample,thefollowingdesignatesthatjointresultsaretobeplottedforjoints101,103,105and107.
PlotOptions
OptionalplotoptionsmaybedesignatedusingthePLTOPTline.Uptothreeallowablecurvesmaybeplottedonthejointdisplacementplots.Designatetheallowablecurvestobeplottedincolumns1116asfollows:
DLDLineAllowable
SNSNAME
MLUSMilitarySpecification
EnterGRincolumns3536ifgridlinesaretobeincludedontheplots.Plotsizeandcharactersizesmayalsobespecifiedincolumns1734.
Thefollowingillustratestheinputtoplotjointresultsforjoints101,103,105and107.DLineandSNAMEallowablecurvesaretobeshownalongwithgridlines.
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2.4SPECTRALWINDANALYSIS
TheDynamicResponseprogramhastheabilitytoperformspectralwindanalyses.Theprogramhasspecializedfeaturesthatgeneratesolutionfilesforextremewindanalysisandwindfatigueanalysis.
2.4.1ExtremeWind
TheprogramcanbeusedtoanalyzewinddynamicallyutilizingaHarriswindspectrumandcreateasolutionfilecontainingendforces,stresses,reactionsanddisplacementsforeachwindvelocitytobeanalyzed.Theseresultscontaindynamicamplificationandcanbecombinedwiththestaticresultsduetoselfweight,etc.
GeneratingthedynamicresultsrequiresthataerodynamicdataandthewindvelocitiestobeanalyzedbespecifiedintheSeastateinput(orSACSmodelfile)whileallotherdataincludinganalysis,spectrumandplotoptionsaredesignatedintheDynamicResponseinputfile.
GeneralModelOptions
TheJOoptionwhichdesignatesthatonlystressesatthejointsaretobecontainedinthesolutionfileshouldbedesignatedincolumns2728ontheOPTIONSlineintheSACSmodelfile.Foreachelement,thedynamicamplificationfactorisbasedonthestressintheelementandisafunctionofthedynamicRMSstressandthestaticstress.Becauseeachmemberinternalloadwillbefactoredbyauniquedynamicamplificationfactorapplicableonlytothatparticularinternalload,internalloadsarenotconsistentwitheachothernoraretheyconsistentwiththeappliedloadingalongthemember.Therefore,stressesandunitycheckcalculationsareonlyvalidatthememberends.
Note:Forextremespectralwindanalysis,theanalysisoptionincolumns1920oftheOPTIONSlineshouldbeleftblank.ThedynamicanalysisoptionDYshouldNOTbespecified.
AerodynamicandWindData
AerodynamicandwinddatamustbespecifiedintheSeastateinputorSACSmodelfile.
TheWINSeastateoptionmustbespecifiedincolumns5658ontheLDOPTline.WindloaddataisspecifiedaftertheLOADline.Eachloadcasedefinedshouldcontainonlywindloadingwiththemeanwindvelocityspecifiedasthewindspeed.
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Note:Eachwindshouldbespecifiedasaseparateloadcase.Asmanywindspeedsanddirectionsasdesiredmaybespecified.
Thefollowingsampleinputshowstwowindcaseswithameanvelocityof100forthe0degreeand90degreedirections.
DynamicResponseOptions
DynamicresponseoptionsincludinganalysisandplotoptionsaredesignatesintheDynamicResponseinputfile.
AnalysisType
TheanalysislabelWINDmustbeenteredincolumns710ontheDROPTlineforspectralwindanalysis.
DampingMethod
OnlystructuraldampinginputontheSDAMPlineisconsideredforspectralwindanalyis.
Note:Becausefluiddampingisnotsupported,theFDAMPlineshouldnotbeusedforspectralwindanalysis.
SpectralWindData
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SpectralwinddataisspecifiedontheSPCWINlineimmediatelyfollowingtheLOADheader.DesignatetheextremewindanalysisoptionEXincolumns89.
Bydefault,600secondsisusedasthemeanwindspeedaveragingtimeusedtocalculatethedynamicamplificationfactors.Thisvaluemaybeoverriddenbyenteringanaveragingtimeoverrideincolumns3944.
Foreachwindspeedtobeanalyzed,aHarriswindspectrumiscreatedbasedonthewindvelocityatthereferenceheightalongwiththespectrumreferencelengthandsurfaceroughnessparametersinputbytheuser.TheprogramusesthisgeneratedHarrisspectrumtodeterminemodelresponses.EnterthereferencelengthandsurfaceroughnesstobeusedfortheHarrisspectrumincolumns4550and5156,respectively.
Bydefault,theprogramcalculatesthespatialcorrelationconstant,enterSKincolumns3536ifaspatialcorrelationconstantisnottobeused.
Thefollowingshowstheinputforaspectralextremewindanalysis.Defaultvaluesforwindaveragingtime,Harrisspectrumreferencelengthandroughnesscoefficientaretobeused.
OutputOptions
Bydefaulttheprogramcreatesacommonsolutionfilecontainingendforces,stresses,reactionsanddisplacementsforeachwindloadcasespecifiedintheSeastateinputfile.
Theprogramalsohastheabilitytoplotageneralizedforcespectrumand/oraresponsespectrumforeachwindspeed.EnterPLincolumns1415and1718respectivelytooutputgeneralizedforceandresponsespectra.
Entertheprintleveldesiredincolumns1112asfollows:
MNMinimumprintcontainingonelineofoutputforeachwindspeedanalyzed
MDModerateprintlevelcontainingonepageofoutputforeachwindanalyzed
MXMaximumprintcontainingdetailedoutputincludingspectrumforeachwindanalyzed.
Static+WindCombinations
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TheDynamicResponsehastheabilitytooptionallycombinespectralwindresultswithstaticresultsaspartoftheextremewindanalysis.Whenusingthisfeature,theprogramcreatesawind+staticcombinationforeachwindloadcase.Ifadifferentjointcheckandmembercheckfactorsarespecifiedhowever,twocombinationsarecreatedforeachwindloadcase.
Note:Thisfeaturerequiresthatthestaticsolutionfileexistpriortoexecutionofthespectralwindanalysis.
ThewindandstaticcombinationinformationisinputusingtheSTCMBline.Enterthefactortobeappliedtothewindloadswhencombinedwiththestaticloadsforthepurposeofmemberandplateelementcheckincolumns812.Thefactortobeappliedtowindloadswhencombinedwithstaticloadsforjointcheckisinputincolumns1317.Entereachofthestaticloadcasestobecombinedwiththeseismicloadcasesandtheloadfactortobeapplied.
Forexample,105%ofloadcases8and9containedinthestaticsolutionfilearetobecombinedwiththewindsolution.Forsamefactorwindloadcasefactorisusedforelementcheckandjointcancheck.
Note:TheSTCMBlineshouldfollowtheSDAMP,FDAMPandMODSELlinesintheinputfile.
CombiningwithStaticResultsManually
Theprogramcreatesacommonsolutionfilecontainingendforces,stresses,reactionsanddisplacementsforeachwindloadcasespecifiedintheSeastateinputfile.BecausetheseresultsareobtainedbycombiningmodalresultsusingRMStechniques,endforces,stresses,etc.havenosignassociatedandaretakenasallpositivevalues.Therefore,whencombiningspectralwindresultswithstaticresultsmanually,thePRSTandPRSCcombineoptionsmustbeused.
2.4.2WindFatigue
TheDynamicResponseprogramcanbeusedtoperformspectralwindfatigueanalysisutilizingaHarriswindspectrum.TheprogramcreatesaFatigueinputfilecontainingfatigueloaddatainconjunctionwiththemodeparticipationfactorsandexecutestheFatiguemoduleautomatically.
GeneratingthedynamicresultsrequiresthataerodynamicandwindinformationbespecifiedintheSeastateinput(orSACSmodelfile)whileallotherdataincludinganalysis,spectrum,fatigueandplotoptionsaredesignatedintheDynamicResponseinputfile.
AerodynamicandWindData
AerodynamicandwinddatamustbespecifiedintheSeastateinputorSACSmodelfile.
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TheWINSeastateoptionmustbespecifiedincolumns5658ontheLDOPTline.WindloaddataisspecifiedaftertheLOADline.Eachloadcasedefinedshouldcontainonlywindloadingwiththemeanwindvelocityspecifiedasthewindspeed.Windloadcasesshouldbespecifiedinorderofincreasingwindspeed,withallwindcasesforaparticulardirectionspecifiedfollowedbyallwindloadcasesforthenextdirection.
Thewindloadsspecifiedareusedtodeterminethefatiguedamage.Astressrangeiscalculatedoreachwindspeedspecified.TheHarrisspectrumisthenusedtodeterminetheprobabiltyofoccurrenceofthatspeed.
Note:Eachwindshouldbespecifiedasaseparateloadcase.Asmanywindspeedsanddirectionsasdesiredmaybespecified.
Thefollowingsampleinputshowswindloadcaseswithspeedrangingfrom2to20fortwodifferentdirections.
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Note:Allwindcasesarespecifiedinthe0degreedirectionbeforethe90degreewindcasesareinput.
DynamicResponseOptions
Dynamicresponseoptionsincludinganalysis,fatigueandplotoptionsaredesignatedintheDynamicResponseinputfile.
AnalysisType
TheanalysislabelWINDmustbeenteredincolumns710ontheDROPTlineforspectralwindanalysis.
DampingMethod
OnlystructuraldampinginputontheSDAMPlineisconsideredforspectralwindanalyis.
Note:Becausefluiddampingisnotsupported,theFDAMPlineshouldnotbeusedforspectralwindanalysis.
SpectralWindData
SpectralwinddataisspecifiedontheSPCWINlineimmediatelyfollowingtheLOADheader.DesignatethewindfatigueanalysisoptionFTincolumns89.
Bydefault,600secondsisusedasthemeanwindspeedaveragingtimeusedtocalculatethedynamicamplificationfactors.Thisvaluemaybeoverriddenbyenteringanaveragingtimeoverrideincolumns3944.TheprogramusesaHarriswindspectrumtodeterminemodalresponses.EnterthereferencelengthandsurfaceroughnesstobeusedfortheHarrisspectrumincolumns4550and5156,respectively.
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Thefollowingshowstheinputforaspectralwindfatigueanalysis.Defaultvaluesforwindaveragingtime,Harrisspectrumreferencelengthandroughnesscoefficientaretobeused.
OutputOptions
TheprogramcreatesaFatigueinputfilecontainingfatigueloaddataforeachwinddirectionspecifiedintheSeastateinputfile.
Theprogramalsohastheabilitytoplotageneralizedforcespectrumand/oraresponsespectrumforeachwindspeed.EnterPLincolumns1415and1718respectivelytooutputgeneralizedforceandresponsespectra.
Entertheprintleveldesiredincolumns1112asfollows:
MNMinimumprintcontainingonelineofoutputforeachwindspeedanalyzed
MDModerateprintlevelcontainingonepageofoutputforeachwindanalyzed
MXMaximumprintcontainingdetailedoutputincludingspectrumforeachwindanalyzed.
FatigueInputData
TheDynamicResponseprogramcreatestheinputfilerequiredbytheFatigueprogrammodule.FatigueinputoptionsarespecifieddirectlyintheDynamicResponseinputfilefollowingtheSPCWINline.AllFatigueinputissupportedandmaybespecifieduptothepointofdefiningfatigueloadcasedata.FatigueloadcasedataiscreatedbytheprogramautomaticallybasedonwindspectrumoptionsspecifiedbytheuserontheWINSPClines.
Foreachwinddirection,windspectrumdatausedtocreatethemodalparticipationinputandthefatigueloadcaseinputisspecifiedonthecorrespondingWINSPCline.Thewinddirectionisdesignatedincolumns713alongwiththefractionoftimethatwindfromthisdirectionoccursspecifiedincolumns1420.
TheWeibullspectrumlabelWEIisenteredincolumns2224alongwiththedistrubutionparametersKandAincolumns2632and3339,respectively.
ThefollowingillustratestheinputrequiredtogeneratetheFatigueinputfortwowinddirections,0and90degrees.Windsfrom0degreesoccur45%andwindsfrom90degreesoccur55%asdesignatedontheWINSPClines.
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Note:EachwinddirectionistreatedasaseparatefatigueloadconditionandmustbedesignatedwithaWINSPCline.
2.5ICEFORCEANALYSIS
IceFatigue
TheDynamicResponseprogramcanbeusedtodeterminefatigueduetovibrationscausedbyiceforces.TheprogramcreatesaFatigueinputfilecontainingfatigueloaddatainconjunctionwiththemodeparticipationfactorsandexecutestheFatiguemoduleautomatically.
AnalysisType
TheanalysislabelVIBRmustbeenteredincolumns710ontheDROPT.Foricevibrationanalysis,enterICEincolumns710ontheFVIBline.
LoadOptions
IceloadingandloadoptionsaredefinedusingtheFVIBandICEinputlinesspecifiedaftertheLOADheaderline.EffectivediameteroverridesusedtocalculateiceloadingmaybespecifiedusingGRPMDandMEMMDlines.
DampingMethod
SpecifythedampingtypeSDOstructuraldampingonly,LFDlinearizedfluiddampingorNFDfornonlinearfluiddampingincolumns1719ontheFVIBline.
Note:Fornonlinearfluiddamping,thefluidforcesarecalculatedateverytimestepduringtheintegration.Thisoptionrequirestheprogramcalculatedfluiddamping
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optionPContheFDAMPline.
Forlinearizedfluiddamping,thedampingamplitudeusedtocalculatetheequivalentlinearfluiddampingmaybeoverriddenbyspecifyingavalueincolumns2027.
EffectiveDiameterOverrides
TheeffectivediameterofmembersthatpenetratetheicesheetmaybeoverriddenusingtheMEMMDortheGRPMDlinesfollowingtheFVIBline.
Formembergroups,enterthegroupnameandtheeffectivediameterontheGRPMDline.Formemberstobemodified,enterthestartjoint,endjointandeffectivediameterontheMEMMDline.
Forexample,groupPL1,PL2andPL3representpilesinsideofthejacketlegthatpenetratetheicesheet.Theeffectivediameterismodifiedto0.001sothatnoiceloadingisappliedtomembersassignedtothesegroups.
IntegrationParameters
IntegrationparametersarestipulatedontheTIMEline.Enterthestartforthebeginningofthetimeintegrationincolumns1120andtheendtimeincolumns2130.Theoutputtimeinterval,minimumintegrationstepandthetolerancefactoraredesignatedincolumns3140,4150and5160,respectively.
Forexample,thefollowingdescribesanicefunctionspecifiedintheinputfile.Thestarttimeis0secondsandendtime25seconds.Outputisrequestedatevery0.25seconds.
FatigueInputData
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TheDynamicResponseprogramcreatestheinputfilerequiredbytheFatigueprogrammodule.FatigueinputoptionsarespecifieddirectlyintheDynamicResponseinputfilefollowingtheFVIBorTIMEline.AllFatigueinputissupportedandmaybespecifieduptothepointofdefiningfatigueloadcasedata.FatigueloadcasedataiscreatedbytheprogramautomaticallybasedonicedataspecifiedbytheuserontheICElines.
ThefollowingshowsfatigueinputoptionscopiedintotheFatigueinputfilecreatedbytheprogram.
IceData
Foreachicefloe,theicedatausedtocreatethemodalparticipationinputandthefatigueloadcaseinputisspecifiedonthecorrespondingICEline.Eachicefloeistreatedasanindividualfatigueloadcase.
Theicethickness,elasticmodulus,staticcrushingstrengthandtopoficeelevationarespecifiedincolumns813,1419,2025and3237,respectively.
Therationoftotallengthtoelasticlengthmustbedesignatedincolumns2631whilethefloedensityisdesignatedincolumns5055.
Theicestiffnessparameterusedtoestimatethestiffnessoftheiceisinputincolumns5661.Thedefaultvalue0.0315representsaninfinitesheetoficeflowingpastaverticalcylinder.
Entertheicevelocityorthevelocityofthefirststepifusingmultiplesteps,incolumns4449.Ifusingmultiplestepstoobtainavariationofresultswithicevelocity,enterthevelocitystepsizeincolumns6267.Thenumberofstepsshouldbestipulatedincolumns6870.
Thetimedurationenteredincolumns7176isthedurationofthefloeandisusedtodeterminethenumberofcyclesfordamagecalculations.
Thefollowingexample,shows5.0thickicefloeinthe40.0degreedirectionwithvelocitiesrangingfrom0.10to0.35.
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OutputOptions
TheicevibrationanalysiscreatesaFatigueinputfileinadditiontooptionalmodalresponseoutput.Optionaloutputoptionsaredesignatedincolumns3258ontheFVIBline.
ModalResponseData
Modalresponsesversustimemaybeprintedand/orplottedbyspecifyingPRTandPLT,respectively,intheoutputoptionsfieldsontheFVIBline.EnterPPTtohavemodalresponsesprintedandplotted.
Note:Modalresponseoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybedesignated.
2.6DYNAMICIMPACTANALYSIS
TheDynamicResponseprogramcanbeusedtodeterminethetransientresponseofastructureresultingfromaccidentalimpactloading.Accidentalimpactloadingresultingfromafloatingvesselanddroppedobjectsareconsidered.TheprogramcanoutputequivalentstaticloadsatdiscreettimestepstobeusedforasubsequentstaticanalysisorincrementalloadsforasubsequentCollapseanalysis.AnalysistypeandanalysisoutputoptionsaredesignatedintheDynamicinputfileinadditiontothebasicanalysisoptions.
2.6.1AnalysisType
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Enter'SHIP'incolumns710ontheDROPTlinetodesignateashipimpactanalysisorenter'DROP'todesignateadroppedobjectanalysis.
2.6.2LoadOptions
ForsshipimpactoradroppedobjectanalysistheinputloadingandloadoptionsareinputfollowingtheLOADheaderlineusingtheSHIP,DRPOBJandTHLOADinputlines.
2.6.3ShipImpactAnalysis
Forashipimpactanalysis,entertheshipparametersincludingtheshipweight,initialvelocity,direction,distancebeforeimpact,impactangle,coefficientoffrictionbetweentheshipandthestructureandtheimpactjointnumberontheSHIPinputlinetogetherwith'SHIP'incolumns912oftheTHLOADlinetodesignateatimehistoryshipimpactanalysis.
2.6.4DroppedObjectAnalysis
Toconductadroppedobjectanalysis,entertheobjectweight,initialvelocity,distancebeforeimpactandtheimpactjointnameontheDRPOBJinputlinetogetherwith'DROP'incolumns912oftheTHLOADlinetodesignatetimehistorydroppedobjectanalysis.
2.6.5DampingMethod
GeneraltimehistoryoptionsaredesignatedontheTHLOADlineimmediatelyfollowingtheLOADheader.SpecifythedampingtypeSDOstructuraldampingonly,LFDlinearizedfluiddampingorNFDfornonlinearfluiddampingincolumns1820.
Note:Fornonlinearfluiddamping,thefluidforcesarecalculatedateverytimestepduringtheintegration.ThisoptionrequirestheprogramcalculatedfluiddampingoptionPContheFDAMPline.
Forlinearizedfluiddamping,thedampingamplitudeusedtocalculatetheequivalentlinearfluiddampingmaybeoverriddenbyspecifyingavalueincolumns2128.
2.6.6InterpolationScheme
Themethodusedtointerpolatebetweentimehistoryinputvaluesisdesignatedincolumns2930ontheTHLOADinputline.EnterLN,QDorCUforlinear,quadraticorcubicinterpolation,respectively.
2.6.7IntegrationParameters
IntegrationparametersarestipulatedontheTIMEline.Enterthestartforthebeginningofthetimehistoryintegrationincolumns1120.Iftheanalysisistoterminatebeforetheendofthetimehistoryinput,entertheendtimeincolumns2130.Theoutputtimeinterval,minimumintegrationstepandthetolerancefactoraredesignatedincolumns3140,4150and5160,respectively.
Forexample,thefollowingdescribesantimehistoryfunctionspecifiedintheinputfile.StructuraldampingonlyisusedinconjunctionwithlinearinterpolationasdesignatedontheTHLOADline.Onetimehistoryfunctionisusedwithdirectionalityfactorsof1.0,1.0and0.5appliedtoitfortheX,YandZdirections,respectively.Thestarttimeis0secondsandendtime25seconds.Outputisrequestedatevery0.25seconds.
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2.6.8OutputOptions
Thetimehistoryearthquakeanalysiscreatesloadcases,printsandplotsmodalresponses,baseshearandoverturningmomentinadditiontojointaccelerations,velocitiesanddisplacements.Analysisoutputoptionsaredesignatedintheoutputoptionsfieldsincolumns3359ontheTHLOADline.
2.6.9LoadCaseCreation
TheDynamicResponseprogramhastheabilitytocreatealoadcasecorrespondingtothetimepointhavingmaximumoverturningmomentand/ormaximumbaseshearbyspecifyingMXMorMXSintheoutputoptionsfieldsontheTHLOADline,respectively.EnterALLifloadcasesaretobecreatedatforalltimepoints,enter'ESL'togenerateequivalentstaticloadsfrasubsequentstaticanalysis,enter'CLP'togenerateincrementalloadsforaCollapseanalysis.
Note:the'ESL'andthe'CLP'optionsaremutuallyexclusive.
2.6.10ModalResponseData
Modalresponsesversustimemaybeprintedand/orplottedbyspecifyingPRTandPLT,respectively,intheoutputoptionsfieldsontheTHLOADline.
2.6.11BaseShearandOverturningMomentPlots
BaseshearandoverturningmomentplotsmaybegeneratedbyenteringPLMandPLSinoneoftheoutputoptionfieldslocatedontheTHLOADline.
2.6.12JointResults
Jointresultsincludingacceleration,velocityanddisplacementmaybeplottedandlistedforuptosixteenjoints.JointplotoptionsarespecifiedintheoutputoptionsfieldsontheTHLOADline.
Jointaccelerationoptionsinclude:
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JMAPrintsmaximumandminimumvaluesforjointaccelerationforeachdirection.
JPASameasJMAplusplotsaccelerationtimehistory
JTASameasJPAplusprintsaccelerationtimehistorydata
Note:Jointaccelerationoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Jointvelocityoptionsinclude:
JMVPrintsmaximumandminimumvaluesforjointvelocityforeachdirection.
JPVSameasJMVplusplotsvelocitytimehistory
JTVSameasJPVplusprintsvelocitytimehistorydata
Note:Jointvelocityoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Jointdisplacementoptionsinclude:
JMDPrintsmaximumandminimumvaluesforjointdisplacementforeachdirection.
JPDSameasJMDplusplotsdisplacementtimehistory
JTDSameasJPDplusprintsdisplacementtimehistorydata
Note:Jointdisplacementoptionsaremutuallyexclusive.Onlyoneoftheoptionsmaybeselected.
Anynumberofjointsmaybedesignatedforplotsandreports.JointstobeoutputarespecifiedusingJTNUMlinesimmediatelyfollowingtheTHLOADline.
Thefollowingillustratesatypicaldynamicresponseinputforashipimpactanalysis.Theanalysisoptionissetto'SHIP'ontheDROPTline.Structuraldampingof5percentisassignedontheSDAMPinputline.TheSHIPlinedescribesa1250tonneshipwithaninitialvelocityof6knotstravellingina180degreedirection.Thedistancebetweentheshipandthestructureisgivenas1meter.TheoutputloadoptionontheTHLOADlineissettogenerateincrementalloadingforaCollapseanalysis.Theresultsareoutputforjoints31P7and701ontheJTNUMline.Theanalysisstarttimeissetto0secondsandtheendtimeissetto2.0secondsontheTIMEinputline.Theresultsareoutputatevery0.01seconds.
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Thefollowingexampleillustratesatypicaldroppedobjectanalysis.Theanalysisoptionissetto'DROP'ontheDROPTline.Structuraldampingof5%isassignedontheSDAMPinputline.Theweightoftheobjectisdefinedas5tonnesontheDRPOBJline.Theinitialvelocityoftheobjectisdefinedas0meterspersecondsandthedistancebeforeimpactisassignedas5meters.Theimpactjointisdefinedas3218.TheoutputloadoptionissettogenerateincrementalloadingforaCollapseanalysisbyentering'CLP'incolumns5153oftheTHLOADline.Resultsareoutputforjoint3218ontheJTNUMline.
3.0COMMENTARY
3.1BASEDRIVENSYSTEM
Theprimarypurposeofthedeflectiondrivensystemistocalculatethestructuralresponseduetoearthquakes.Forthispurpose,allsupportpointsareassumedtobemovingwiththeground.Sinceamodalanalysisisbeingused,eachmodecanbeconsideredtoactindependentlyoftheothermodesandcanbeshowntoactasasingledegreeoffreedomsystemasfollows:
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Theforcedeflectionrelationforanelasticlinearstructurecanbeexpressedas:
(1)
where{F}istheforcevector,[K]islinearstiffnessmatrixand{d}isthedeformationvector.
Separatingthefreeandthereactiondegreesoffreedom,theforcedeflectionrelationcanbeexpressedas:
(2)
wheretheFandRsubscriptsdifferentiatethefreeandreactiondegreesoffreedom.
Forabasedrivensystem,theloadinginthefreedegreesoffreedomisduetotheinertiaandcanbeexpressedas:
(3)
wheredFaretheaccelerationsofthefreedegreesoffreedomandMFFisthemassmatrix.
Fromequation(2),
(4)
whichbecomes:
(5)
Thedeformationofafreedegreeoffreedomcanbeexpressedintermsofdeformationduetoexternalloadsanddeformationduetomovementofthesupports,sothat
(6)
wheredFEisduetoexternalloadsanddFSisduetomovementofthesupports.Equation(4)becomes
(7)
bydefinition
(8)
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sothat
(9)
or
(10)
Substituting(10)into(6)yieldsthefollowing:
(11)
Differentiatingbothsidestwicewithrespecttotime,produces
(12)
Substitutingequation(11)and(12)intoequation(5),
(13)
Thedeformationofthefreedegreesoffreedomwiththebasefixedcanbeexpressedintermsofthenormalvibrationmodesoftherestrainedstructuresuchthat
(14)
whereFFaremodeshapesandrepresentsmodalcoordinates.Substitutingequation(14)intoequation(13)yieldsthefollowing:
(15)
Notingthattheeigenvalues/vectorrelationofthemassmatrix,
(16)
wherenarethenaturalfrequenciesoftherestrainedstructure,substituting(16)into(15)andmultiplyingbythemodeshapes,
(17)
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Notingthatthegeneralizedmassisexpressedas:
(18)
equation(17)becomes:
(19)
or
(20)
DefiningtheparameterRas
(21)
equation(20)maybeexpressedas:
(22)
Modaldampingcanbeaddedsot