Title of article
Combinationofmodalresponses:Aclosed-formformulationforrigidresponsecoefficientOriginalResearchArticle
Author/Authors
RakeshK.Saigal، نويسنده , , AbhinavGupta، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2007
Pages
8
From page
2075
To page
2082
Abstract
RecentstudiesconductedbyUSNuclearRegulatoryCommission(USNRC)forcombiningmodalresponsesinaresponsespectrummethodofseismicanalysisanddesignhaveemphasizedthateachmodalresponsequantityshouldbeseparatedintodamped-periodicandrigidpartsbeforecombiningthecontributionsfromdifferentmodes.Thedamped-periodicpartsofmodalresponsesarecombinedusingthedouble-sumequationwhereastherigidpartsarecombinedalgebraically.Aparticularmodalresponsequantityisseparatedintodamped-periodicandrigidpartsusingthe“rigidresponsecoefficient”.TheUSNRCsponsoredstudyrecommendsthecalculationofrigidresponsecoefficientbyeithertheLindley–YowapproachorGuptamethod.WhileLindley–Yowʹsmethodhasaheuristicbasisandgivesincorrectresultsinlowfrequencyregion,Guptaʹsmethodisbasedonnumericalstudiesoffree-fieldearthquakemotionsandworkswellinthefrequencyregionsofinterestforafree-fieldgroundmotion.Aclosed-formsolutionwasdevelopedbyHahnandValentiin1997usingafrequencydomainapproach.Withappropriatesimplifications,theirworkcanbeshowntoresultinanexpressionwhichisverysimilartothatgivenbyGupta.Itmustbenotedthattheearthquakeinputtothesecondarysystemssuchaspipingandequipmentisdefinedbyafloormotionandnotafree-fieldgroundmotion.Thefrequencycharacteristicsofafloormotionareverydifferentfromthoseofafree-fieldgroundmotion.Inthispaper,westudythevalidityofexistingformulationsforthecaseoffloormotionsanddevelopaclosed-formsolutionbasedonatimedomainapproachtoexplainthebehaviorofrigidresponsecoefficient.Theformulationisthenusedtoexplainthenatureofvariationinrigidresponsecoefficientforgroundaswellasfloormotions.Itisshownthattheproposedformulationanditssimplifiedformgivesresultsthatareidenticaltothoseevaluatednumericallyinthecompletefrequencyregionofinterest.
Journal title
Nuclear Engineering and Design Eslah
Serial Year
2007
Journal title
Nuclear Engineering and Design Eslah
Record number
941427
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