A method for stochastic seismic response analysis of non-classically damped structures

(整期优先)网络出版时间:2004-01-11
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Amethodtocalculatethestationaryrandomresponseofanon-classicallydampedstructureisproposedthatfeaturesclearly-definedphysicalmeaningandsimpleexpression.Themethodisdevelopedinthetrequencydomain.Theexpressionoftheproposedmethodconsistsofthreeterms,i.e.,modalvelocityresponse,modaldisplacementresponse,andcoupled(betweenmodalvelocityandmodaldisplacementresponse).Numericalresultsfromtheparametricstudyandthreeexamplestructuresrevealthatthemodalvelocityresponsetermandthecoupledtermareimportanttostructuralresponseestimatesonlyforadynamicsystemwithatunedmassdamper.Intypicalcases,themodaldisplacementtermcanprovideresponseestimateswithsatisfactoryaccuracybyitself,sothatthemodalvelocitytermandcoupledtermmaybeignoredwithoutlossofaccuracy.Thisisusedtosimplifvtheresponsecomputationofnon-classicallydampedstructures.Forthewhitenoiseexcitation,threemodalcorrelationcoefficientsmclosedformarederived.Toconsiderthemodalvelocityresponsetermandthecoupledterm,asimplifiedapproximationbasedonwhitenoiseexcitationisdevelopedforthecasewhenthemodalvelocityresponseisimportanttothestructuralresponses.Numericalresultsshowthattheapproximateexpressionbasedonwhitenoiseexcitationcanprovidestructuralresponseswithsatisfactoryaccuracy.