船舶结构运行模态参数辨识研究.pdf

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1、第15卷第3期2011年3月船舶力学JournalofShipMechanicsV01．15No．3Mal-．2011ArticleID：l007-7294(2011)03—D313一12StudyonOperationalModalParametersIdentificationofShipStructures．HANGDa-zheng,HONGMing,ZHOULi(SchoolofNavalArchitectureEngineering，FacultyofVehicleEngineeringandMechanics，St

2、ateKeyLaboratoryofStructuralAnalysisforIndustrialEquipment，DalianUniversityofTechnology，Dalian116024，China)Abstract：Operationalmodalanalysisisaprocedurewhichallowsextractingmodalparametersfromastructureonlybasedonresponsedataunderambientexcitation．Itisbasedontheassu

3、mptionthatinputtothestructureisstationarywhitenoise．Inthispaper,theapplicationfeasibilityofoperationalmodalanalysisonshipstructuresisdiscussed．Andbandstopfilterisproposedtofiltertheobviousharmonicenergytoimprovetheidentificationprecisionofrealmodes．Thentheauto—cross

4、spectrumdensitymethodisdiscussedandverifiedbyasimplysupportedbeamexperimentwithwhitenoiseandharmonicexcitations．Thi8methodistestifiedtobeeffectivetoidentifythenaturalfrequenciesandoperatingdeflectionshapes．Soitisfeasibleandsignificanttoidentifymodalparametersofships

5、tructuresunderambientexcitations．Keywords：operationalmodalanalysis；shipstructures；parameteridentification；bandstopfilterCI．Cnumber：11661．4Documentcode：A1IntroductionModalanalysismethodincludesexperimentalmodalanalysis(EMA)methodandopera-tionalmodalanalysisfOMA)．Oper

6、ationalmodalanalysis【11procedureisanefficienttechniquetoidentifymodalpropertiesofstructuresonlybasedonresponsedataduringoperation．Com—paringwithtraditionalmodalanalysismethods，OMAhassometypicalcharacteristicsasfol-lowst刁：(1)OMAcallextractmodalparametersoflargeconstr

7、uctionsonlyfromresponsedataan—derambientexcitationswithoutadditionalexcitations．ThisisalargeimprovementtotraditionalmethodswhichCallnotidentifymodalpropertiesefficientlybecauseoffailingtoapplyeffectiveexcitations．(2)TheidentifiedresultswithOMAcanreflecttherealdynami

8、ccharacteristicofthestruc—tureduringoperation．Itcanbeusedtotestthechangesofmodalparameterscausedbyambi—entexcitationandthestructurehealthm