简介：Localizednatureofdamageinstructuresrequireslocalmeasurementsforstructuralhealthmonitoring.Thelocalmeasurementmeanstomeasurethelocal,usuallyhighermodesofthevibrationinastructure.Threefundamentalissuesaboutthelocalmeasurementforstructuralhealthmonitoringincluding(1)thenecessityofmakinglocalmeasurement,(2)thedifficultyofmakinglocalmeasurementand(3)howtomakelocalmeasurementareaddressedinthispaper.Theresultsfromboththeanalysisandthetestsshowthatthelocalmeasurementcansuccessfullymonitorthestructuralhealthstatusaslongasthelocalmodesareexcited.Unfortunately,theresultsalsoillustratethatitisdifficulttoexcitelocalmodesinastructure.Therefore,inordertocarrystructuralhealthmonitoringintoeffect,wemust(1)ensurethatthelocalmodesareexcited,and(2)deployenoughsensorsinastructuresothatthelocalmodescanbemonitored.

简介：Onebranchofstructuralhealthmonitoring(SHM)utilizesdynamicresponsemeasurementstoassessthestructuralintegrityofcivilinfrastructures.Inparticular,modalfrequencyisawidelyadoptedindicatorforstructuraldamagesinceitssquareisproportionaltostructuralstiffness.However,ithasbeendemonstratedinvariousSHMprojectsthatthisindicatorissubstantiallyaffectedbyfluctuatingenvironmentalconditions.Inordertoprovidereliableandconsistentinformationonthehealthstatusofthemonitoredstructures,itisnecessarytodevelopamethodtofilterthisinterference.Thisstudyattemptstomodelandquantifytheenvironmentalinfluenceonthemodalfrequenciesofreinforcedconcretebuildings.Dailystructuralresponsemeasurementsofatwenty-twostoryreinforcedconcretebuildingwerecollectedandanalyzedoveraone-yearperiod.TheBayesianspectraldensityapproachwasutilizedtoidentifythemodalfrequenciesofthisbuildinganditwasclearlyseenthatthetemperatureandhumidityfluctuationinducednotablevariations.Amathematicalmodelwasdevelopedtoquantifytheenvironmentaleffectsandmodelcomplexitywastakenintoconsideration.BasedonaTimoshenkobeammodel,thefullmodelclasswasconstructedandotherreduced-ordermodelclasscandidateswereobtained.Then,theBayesianmodalclassselectionapproachwasemployedtoselecttheonewiththemostsuitablecomplexity.Theproposedmodelsuccessfullycharacterizestheenvironmentalinfluenceonthemodalfrequencies.Furthermore,theestimateduncertaintyofthemodelparametersallowsforassessmentofthereliabilityoftheprediction.Thisstudynotonlyimprovestheunderstandingaboutthemonitoredstructure,butalsoestablishesasystematicapproachforreliablehealthassessmentofreinforcedconcretebuildings.

简介：Theconceptofhealthmonitoringisakeyaspectofthefieldofmedicinethathasbeenpracticedforalongtime.Acommonlyuseddiagnosticandhealthmonitoringpracticeispulsediagnosis,whichcanbetracedbackapproximatelyfivethousandyearsintherecordedhistoryofChina.Withadvancesinthedevelopmentofmodemtechnology,theconceptofhealthmonitoringofavarietyofengineeringstructuresinseveralapplicationshasbeguntoattractwidespreadattention.Ofparticularinterestinthisstudyisthehealthmonitoringofcivilstructures.Itseemsnatural,andevenbeneficial,thatthesetwohealth-monitoringmethods,oneasappliestothehumanbodyandtheothertocivilstructures,shouldbeanalyzedandcompared.Inthispaper,thebasicconceptsandtheoriesofthetwomonitoringmethodsarefirstdiscussed.Similaritiesarethensummarizedandcommentedupon.Itishopedthatthiscorrelationanalysismayhelpprovidestructuralengineerswithsomeinsightsintotheintrinsicconceptofusingpulsediagnosisinhumanhealthmonitoring,whichmaybeofsomebenefitinthedevelopmentofmodernstructuralhealthmonitoringmethods.

简介：StructuralhealthmonitoringofRCstructuresunderseismicloadshasrecentlyattractedmuchattentionintheearthquakeengineeringresearchcommunity.Inthisstudy,apiezoceramic-baseddevicecalled'smartaggregate'wasusedforthehealthmonitoringofRCframestructuresunderearthquakeexcitations.ThreeRCmomentframesinstrumentedwithsmartaggregatesweretestedusingashaketablewithdifferentgroundexcitationintensities.Distributedpiezoceramic-basedsmartaggregateswereembeddedintheRCstructuresandusedtomonitortheirhealthconditionduringthetests.Thesensitivityandeffectivenessoftheproposedpiezoceramic-basedapproachwereinvestigatedandevaluatedbyanalyzingthemeasuredresponses.Thedisplacementductilitydemandofthestructuralmemberswascalculatedandcomparedwiththedamageindexdeterminedfromthehealthmonitoringsystem.Thecomparisonshowsthatthedamageindexiscompatiblewiththecalculatedductilitydemand.

简介：Developmentandtestingofaseriallymultiplexedfiberopticsensorsystemisdescribed.Thesensordiffersfromconventionalfiberopticacousticsystems,asitiscapableofsensingAEemissionsatseveralpointsalongthelengthofasinglefiber.Multiplexingprovidesforsinglechanneldetectionofcracksandtheirlocationsinlargestructuralsystems.AnalgorithmwasdevelopedforsignalrecognitionandtaggingoftheAEwaveformsfordetectionofcracklocations.Laboratoryexperimentsonplainconcretebeamsandpost-tensionedFRPtendonswereperformedtoevaluatethecrackdetectioncapabilityofthesensorsystem.Theacousticemissionsensorwasabletodetectinitiation,growthandlocationofthecracksinconcreteaswellasintheFRPtendons.TheAEsystemispotentiallysuitableforapplicationsinvolvinghealthmonitoringofstructuresfollowinganearthquake.

简介：Accurateestimationofstiffnesslossisachallengingprobleminstructuralhealthmonitoring.Inthisstudyorthogonalwaveletdecompositionisusedforidentifyingthestiffnesslossinasingledegreeoffreedomspring-mass-dampersystem.Theeffectsofexcitationfrequencyonaccuracyofdamagedetectionisinvestigated.Resultsshowthatpseudo-aliaseffectscausedbytheorthogonalwaveletdecomposition(OWD),affectdamagedetectability.Itisdemonstratedthattheproposedapproachissuitablefordamagedetectionwhentheexcitationfrequencyisrelativelylow.Thisstudyshowshowaprioriknowledgeaboutthesignalandabilitytocontrolthesamplingfrequencycanenhancedamagedetectability.

简介：在这篇论文，一个新奇参量的基于模型的分解方法为变化时间的结构监视的结构的健康被建议。为这个目的，先进功能系列的时间依赖者汽车回归的动人的一般水准(FS-TARMA)技术被用来估计在参量的信号分解计划使用的参数和革新变化。另外，一个唯一的特征抽取和减小方法基于分解信号，已知的同样潜伏的部件(LC)，被建议。为了在实验室评估建议方法，数字模拟和试验性的研究的效率，在变化时间的结构上被进行，在损坏的各种各样的类型被介绍的地方。模糊专家系统(FES)被用作一个分类工具当时，证明建议方法成功地识别不同结构的条件与另外的方法相比基于非减少、平常的特征抽取。

简介：Cable-membranestructureshavesmallrigidityandarehighlysensitivetowind.Structuralhealthmonitoringisnecessarytoensuretheserviceabilityandsafetyofthestructure.Inthisresearch,thedesignmethodofastructuralhealthmonitoringsystemisusingthecharacteristicsofacable-membranestructure.TakingtheYueyangSanheAirportTerminalasanexample,afiniteelementmodelisestablishedtodeterminethecriticalstructuralcomponents.Next,theengineeringrequirementsandtheframeworkofthemonitoringsystemarestudiedbasedontheresultsofnumericalanalysis.Thespecificimplementationofthestructuralhealthmonitoringisthencarriedout,whichincludessensorselection,installationandwiring.TheproposedframeworkissuccessfullyappliedtothemonitoringsystemfortheYueyangAirportterminalbuilding,andthesynchronousacquisitionoffiberBragggratingandaccelerationsensorsignalsisimplementedinaninnovativeway.Thesuccessfulimplementationandoperationofstructuralhealthmonitoringwillhelptoguaranteethesafetyofthecablemembranestructureduringitsservicelife.