《土木工程专业英语 第2版》 课件 Unit10 Supplemental Energy Dissipation State of the art and State of the practice

Unit10SupplementalEnergyDissipation:State-of-the-artandState-of-the-practiceEnglishforCivilEngineering——Teacher:Prof.ZhengLuE-mail:luzheng111@（SchoolofCivilEngineering,TONGJIUNIVERSITY）Unit10SupplementalEnergyDissipation:

State-of-the-artandState-of-the-practice

10.1Introduction

综述减震构件的类型10.2BasicPrinciples

公式原理10.3PassiveEnergyDissipation被动系统MetallicdampersFrictiondamperVEdampersViscousfluiddampersTunedmassdampersTunedliquiddampers10.4Active,HybridandSemi-activeControlSystems

主动、混合、半主动系统Hybrid

mass

damper

systemsActivemassdampersystemsSemi-active

damper

systemsSemi-activeControllableFluidDampers10.1Introduction

Inrecentyears,

innovative

meansofenhancingstruc­turalfunctionalityandsafetyagainstnaturalandman-madehazards

havebeeninvariousstagesofresearchanddevelopment.Byandlarge,theycanbegroupedintothreebroadareasasshowninTable10-1.1).baseisolation;2).passiveenergydissipation；3).activecontrol.抵御自然和人为灾害提高结构功能和安全性的方法：三大类innovative创新，革新；stages

阶段；byandlarge大体上，总的来说；10.1Introduction

Ofthethree,baseisolationcannowbeconsideredamorematuretechnologywithwiderapplicationsascom­paredwiththeothertwo.Passiveenergydissipationsystemsencompass

arangeofmaterialsanddevicesforenhancingdamping,stiff­nessandstrength,andcanbeusedbothforseismichaz­ardmitigationandforrehabilitation

ofagingordeficientstructures.Ingeneral,suchsystemsarecharacterizedbytheircapabilitytoenhanceenergydissipationinthestructuralsystemsinwhichtheyareinstalled.Thesedevicesgenerallyoperateonprinciplessuchasfrictionalsliding,yieldingofmetals,phasetransform­ationinmetals,deformationofviscoelastic(VE)solidsorfluidsandfluidorificing.基础隔震相对成熟和应用；被动控制包括很多材料和设备（提高阻尼、刚度、强度）。同时用于减少地震灾害和修复年久破损结构。encompass

，围绕，包围；

mitigation，缓解，减轻；rehabilitation，修复；dificient，有缺陷的；

viscoelastic，粘弹性；orifice，孔口；onprinciples，基于原理；

phasetransformationinmetals，金属相变。10.1Introduction

Active/hybrid/semi-activecontrolsystemsareforcedeliverydevicesintegratedwithreal-timeprocessingevaluators/controllersandsensorswithinthestructure.Theyactsimultaneouslywiththehazardousexcitationtoprovideenhancedstructuralbehaviorforimprovedserviceandsafety.Researchtodatehasalsoreachedthestagewhereactivesystemshavebeeninstalledinfull-scalestructuresforseismichazardmitigation.主动、混合、半主动控制实时评估和控制传感器目前可安装在全尺结构simultaneously

，同时；research

to

date

，迄今为止的研究。10.1Introduction

Thispaperprovidesanassessmentofthestate-of-the-artandstate-of-the-practiceofthisexciting,andstillevolving,technology.Also,includedinthediscussionaresomebasicconcepts,thetypesofstructuralcontrolsystemsbeingusedanddeployed,andtheiradvantagesandlimitationsinthecontextofseismicdesignandretrofitofcivilengineeringstructures.文章思路

技术评估+结构控制体系的基本概念、种类、优缺点。state-of-the-artandstate-of-the-practice，发展水平和实践；

inthecontextof，在……情况下，在……背景下。10.2Basic

Principles

10.2Basic

Principles

10.2Basic

Principles

Anactivestructuralcontrolsystem,ontheotherhand,hasthebasicconfigurationasshownschematicallyinFig.10-1c.Itconsistsof:1)sensorslocatedaboutthestructuretomeasureeitherexternalexcitations,orstructuralresponsevariables,orboth.2)devicestoprocessthemeasuredinformationandtocomputenecessarycontrolforcesneededbasedonagivencontrolalgorithm.3)actuators,usuallypoweredbyexternalsources,toproducetherequiredforces.主动控制系统的组成。algorithm，算法；actuators，执行器，激励器。10.2Basic

Principles

Whenonlythestructuralresponsevariablesaremeas­ured,thecontrolconfigurationisreferredtoasfeedbackcontrolsincethestructuralresponseiscontinuallymoni­toredandthisinformationisusedtomakecontinualcor­rectionstotheappliedcontrolforces.Afeedforwardcontrolresultswhenthecontrolforcesareregulatedonlybythemeasuredexcitation,whichcanbeachieved,

forearthquakeinputs,bymeasuringaccelerationsatthestructuralbase.Inthecasewheretheinformationonboththeresponsequantitiesandexcitationareutilizedforcontroldesign,thetermfeedback-feedforwardcon­trolisused.句式比较繁杂。反馈控制的机理。be

referredtoas，被称为，视为；

feedforward，前馈控制。10.2Basic

Principles

10.2Basic

Principles

Otheradvantagesassociatedwithactivecontrolsystemscanbecited;amongthemare:1)enhancedeffectivenessinresponsecontrol;thedegreeofeffectivenessis,byandlarge,onlylimitedbythecapacityofthecontrolsystems.2)relativeinsensitivitytositeconditionsandgroundmotion.3)applicabilitytomulti-hazardmitigationsituations;anactivesystemcanbeused,forexample,formotioncontrolagainstbothstrongwindandearthquakes.4)selectivityofcontrolobjectives;onemayemphasize,forexample,humancomfortoverotheraspectsofstructuralmotionduringnoncriticaltimes,whereasincreasedstructuralsafetymaybetheobjectivedur­ingseveredynamicloading.主动控制的其他优点。cite，举例;byandlarge，总的来说。10.2Basic

Principles

Itisusefultodistinguishamongseveraltypesofactivecontrolsystemscurrentlybeingusedinpractice.ThetermhybridcontrolgenerallyreferstoacombinedpassiveandactivecontrolsystemasdepictedinFig.10-1d.Sinceaportionofthecontrolobjectiveisaccomplishedbythepassivesystem,lessactivecontroleffort,implyinglesspowerresource,isrequired.Similarcontrolresourcesavingscanbeachievedusingthesemi-activecontrolschemesketchedinFig.10-1e,wherethecontrolactuatorsdonotaddmechanicalenergydirectlytothestructure,hencebounded-input/bounded-output

stabilityisguaranteed.Semi-activecontroldevicesareoftenviewedascontrollablepassivedevices.Asidebenefitofhybridandsemi-activecontrolsys­temsisthat,inthecaseofapowerfailure,thepassivecomponentsofthecontrolstilloffersomedegreeofpro­tection,unlikeafullyactivecontrolsystem.混合控制和半主动控制的特点和优势portion，部分；

imply，意味着；bound，边界。10.2Basic

Principles

10.3Passive

Energy

Dissipation

DiscussionspresentedbelowarecenteredaroundsomeofthemorecommondeviceswhichhavefoundapplicationsinPED.10.3.1

MetallicYieldDampersOneoftheeffectivemechanismsavailableforthedis­sipationofenergyinputtoastructurefromanearth­quakeisthroughinelasticdeformationofmetals.ManyofthesedevicesusemildsteelplateswithtriangularorXshapessothatyieldingisspreadalmostuniformlythroughoutthematerial.AtypicalX-shapedplatedamperorADAS(addeddampingandstiffness)deviceisshowninFig.10-2.Otherconfigurationsofsteelyieldingdevices,usedmostlyinJapan,includebendingtypeofhoneycomband

slit

dampersandshearpaneltype.Othermaterials,suchasleadandshape-memoryalloys,havealsobeenevaluated.Someparticularlydesirablefeaturesofthesedevicesaretheirstablehystereticbehavior,low-cyclefatigueproperty,longtermreliability,andrelativeinsensitivitytoenvironmentaltemperature.金属屈服阻尼器mildsteelplates，低碳钢板；

uniformly，均匀，一体；

honeycomb

，蜂窝，弯曲型蜂窝；slit，狭缝；

alloys，合金。10.3Passive

Energy

Dissipation

Aftergainingconfidenceintheirperformancebasedprimarilyonexperimentalevidence,implementationofmetallicdevicesinfull-scalestructureshastakenplace.TheearliestimplementationsofmetallicdampersinstructuralsystemsoccurredinNewZealandandJapan.Anumberoftheseinterestingapplicationsarereported.MorerecentapplicationsincludetheuseofADASdampersintheseismicupgradeofexistingbuild­ingsinMexicoandintheUSA.TheseismicupgradeprojectdiscussedininvolvestheretrofitofaWellsFargoBankbuildinginSanFrancisco,CA.Thebuildingisatwo-storynonductileconcreteframestructureoriginallyconstructedin1967andsubsequentlydamagedinthe1989LomaPrietaearthquake.AtotalofsevenADASdeviceswereemployed,eachwithayieldforceof150kips.Bothlinearandnonlinearanalyseswereusedintheretrofitdesignprocess.ADAS在SanFrancisco的应用。kips

，千磅。10.3Passive

Energy

Dissipation

Avariationofthedevicesdescribedabovebutoperatingonthesamemetallicyieldingprincipleisthetension/compressionyieldingbrace,alsocalledtheunbondedbrace,whichhasfoundapplicationsinJapanandtheUSA.AsshowninFig.10-4,anunbondedbraceisabracingmemberconsistingofacoresteelplateencasedinaconcrete-filledsteeltube.Aspecialcoatingisprovidedbetweenthecoreplateandconcreteinordertoreducefriction.Thecoresteelplateprovidesstableenergydissipationbyyieldingunderreversedaxialload­ing,whilethesurroundingconcrete-filledsteeltuberesistscompressionbuckling.介绍了金属屈服构件的一种变体。unbonded

，无粘结的；encased，被包住10.3Passive

Energy

Dissipation

10.3.2

Friction

DampersFrictiondampersutilizethemechanismofsolidfric­tion

thatdevelopsbetweentwosolidbodies

slidingrela­tivetooneanothertoprovidethedesiredenergydissi­pation.Severaltypesoffrictiondampershavebeendevelopedforthepurposeofimprovingseismicresponseofstructures.AnexampleofsuchadeviceisdepictedinFig.10-5.Duringcyclicloading,themechanismenforcesslippageinbothtensileandcompressivedirections.Gen­erally,frictiondevicesgeneraterectangularhystereticloopssimilartothecharacteristicsofCoulombfriction.Afterahystereticrestoringforcemodelhasbeenvali­datedforaparticulardevice,itcanbereadilyincorpor­atedintoanoverallstructuralanalysis.摩擦阻尼器的原理。enforces，施加；vali­dated，有效；coulombfriction

，库伦摩擦10.3Passive

Energy

Dissipation

10.3.3

ViscoelasticDampersViscoelastic(VE)materialsusedinstructuralapplicationsareusuallycopolymersorglassysubstancesthatdissi­pateenergythroughsheardeformation.AtypicalVEdamper,whichconsistsofVElayersbondedwithsteelplates,isshowninFig.10-6.Whenmountedinastructure,sheardeformationandhenceenergydissipationtakesplacewhenstructuralvibrationinducesrelativemotionbetweentheoutersteelflangesandthecenterplates.Sig­nificantadvancesinresearchanddevelopmentofVEdampers,particularlyforseismicapplications,havebeenmadeinrecentyearsthroughanalysesandexperimentaltests.粘弹性阻尼器的原理。viscoelastic

，粘弹性；copolymers

，共聚物；mounted，安装。10.3Passive

Energy

Dissipation

10.3.3

ViscoelasticDampersAseismicretrofitprojectusingVEdampersbeganin1993forthe13-storySantaClaraCountybuildinginSanJose,CA.Situatedinahighseismicriskregion,thebuildingwasbuiltin1976.Itisca64minheightandnearlysquareinplan,with51m×51montypicalupperfloors.Theexteriorcladdingconsistsoffull-heightglazingontwosidesandmetalsidingontheothertwosides.Theexteriorcladding,however,provideslittleresistancetostructuraldrift.Theequivalentviscousdampinginthefundamentalmodewas<1%ofcritical.对结构的抗震升级（加固）

cladding，包层，电镀；critical，临界值；glazing，玻璃；10.3Passive

Energy

Dissipation

10.3.4

Viscous

fluid

dampersTheviscousfluid(VF)devicesdevelopedrecentlyincludeviscouswallsandVFdampers.Theviscouswall,developedbySumitomoConstructionCompany,con­sistsofaplatemovinginathinsteelcasefilledwithhighlyVF.TheVFdamper,widelyusedinthemilitaryandaerospaceindustryformanyyears,hasrecentlybeenadaptedforstructuralapplicationsincivilengineering.AVFdampergenerallyconsistsofapistonwithinadamperhousingfilledwithacompoundofsiliconeorsimilartypeofoil,andthepistonmaycontainanumberofsmallorificesthroughwhichthefluidmaypassfromonesideofthepistontotheother.

Thus,VFdam­persdissipateenergythroughthemovementofapistoninahighly

VFbasedontheconceptoffluidorificing.粘质液体阻尼器的原理和工作方式。aerospace，航空航天；piston，活塞；

silicone，硅酮。10.3Passive

Energy

Dissipation

10.3.5TunedMassDampersEarlyapplicationsoftunedmassdampers(TMDs)havebeendirectedtowardmitigationofwind-inducedexcitations.Recently,numericalandexperimentalstud­ieshavebeencarriedouttoexaminetheeffectivenessofTMDsinreducingseismicresponseofstructures.ItisnotedthatapassiveTMDscanonlybetunedtoasinglestructuralfrequency.Whilethefirst-moderesponseofaMDOFstructurewithTMDscanbesubstantiallyreduced,thehighermoderesponsemayinfactincreaseasthenumberofstoriesincreases.Forearthquake-typeexci­tations,theresponsereductionislargeforresonantgroundmotionsanddiminishesasthedominantfre­quencyofthegroundmotiongetsfurtherawayfromthestructure’snaturalfrequencytowhichtheTMDsistuned.调谐质量阻尼器的减震特点。betuned

，调谐；resonant，共振。10.3Passive

Energy

Dissipation

10.3.6

TunedLiquidDampers

Thebasicprincipleinvolvedinapplyingatunedliquiddampers(TLDs)toreducethedynamicresponseofstructuresisquitesimilartothatdiscussedabovefortheTMDs.Ineffect,asecondarymassintheformofabodyofliquidisintroducedintothestructuralsystemandtunedtoactasadynamicvibrationabsorber.However,inthecaseofTLDs,thedamperresponseishighlynon­lineardueeithertoliquidsloshingorthepresenceoforifices.TLDshavealsobeenusedforsuppressingwind-inducedvibrationsoftallstructures.IncomparisonwithTMDs,theadvantagesassociatedwithTLDsincludelowinitialcost,virtually

freeofmaintenanceandeaseoffrequencytuning.TheTLDapplicationshavetakenplaceprimarilyinJapanforcontrollingwind-inducedvibration.ExamplesofTLD-controlledstructuresincludeairporttowersandtallbuildings.调谐液体阻尼器的机理和应用特点及优势sloshing

，冲击，晃荡；

suppressing，抑制；

virtually

，几乎。10.4Active,HybridandSemi-activeControlSystems

Therapidgrowthofresearchinterestanddevelopmentofactive/hybridandsemi-activestructuralcontrolsys­temsisinpartduetoseveralcoordinated

researchefforts,largelyinJapanandtheUSA,markedbyaseriesofmilestoneslistedinTable10-2.Indeed,themostchal­lengingaspectofactivecontrolresearchincivilengin­eeringisthefactthatitisanintegrationofanumberofdiversedisciplines,

someofwhicharenotwithinthedomainoftraditionalcivilengineering.Theseincludecomputerscience,dataprocessing,controltheory,materialscience,sensingtechnology,aswellasstochas­ticprocesses,structuraldynamics,andwindandearth­quakeengineering.Thesecoordinatedeffortshavefacili­tatedcollaborativeresearcheffortsamongresearchersfromdiversebackgroundsandacceleratedtheresearch-to-implementationprocessasoneseestoday.主动控制是多学科综合的研究领域coordinated

，协同；

disciplines，学科；

stochas­tic

，随机的。10.4Active,HybridandSemi-activeControlSystems

Asalludedtoearlier,thedevelopmentofactive,hybrid,andsemi-activecontrolsystemshasreachedthestageoffull-scaleapplicationstoactualstructures.Otherthantheseinstallationsinbuildingstructuresandtow­ers,mostofwhichareinJapan,

15bridgetowershaveemployedactivesystemsduringerectioninaddition.Mostofthesefull-scalesystemshavebeensub­jectedtoactualwindforcesandgroundmotionsandtheirobservedperformancesprovideinvaluableinfor­mationintermsof:1)validatinganalyticalandsimulationproceduresusedtopredictactualsystemperformance2)verifyingcomplexelectronic-digital-servohydraulicsystemsunderactualloadingconditions.3)verifyingcapabilityofthesesystemstooperateorshutdownunderprescribedconditions.主动系统观测到的数据的用途。Erection，建造；prescribed，规定的；asalludedtoearlier，如前文所述；

electronic-digital-servohydraulicsystems，数电液压系统。10.4Active,HybridandSemi-activeControlSystems

Describedbelowareseveralofthesesystemstogether,insomecases,withtheirobservedperformances.Alsoaddressedareseveralpracticalissuesinconnectionwithactualstructuralapplicationsofthesesystems.10.4.1HybridMassDamperSystemsTheHMDisthemostcommoncontroldeviceemployedinfull-scalecivilengineeringapplications.HMDisacombinationofapassiveTMDsandanactivecontrolactuator.TheabilityofthisdevicetoreducestructuralresponsesreliesmainlyonthenaturalmotionoftheTMDs.TheforcesfromthecontrolactuatorareemployedtoincreasetheefficiencyoftheHMDandtoincreaseitsrobustnesstochangesinthedynamiccharacteristicsofthestructure.TheenergyandforcesrequiredtooperateatypicalHMDarefarlessthanthoseassociatedwithafullyAMPsystemofcom­parableperformance.下文重点讲述系统、应用的表现和连接方面的问题。HMD的工作特点和优点。com­parable，可比的。10.4Active,HybridandSemi-activeControlSystems

AnexampleofsuchanapplicationistheHMDsysteminstalledintheSendagayaINTESbuildinginTokyoin1991.AsshowninFig.10-10,theHMDwasinstalledatopthe11thfloorandconsistsoftwomassestocontroltransverseandtorsionalmotionsofthestructure,whilehydraulicactuatorsprovidetheactivecontrolcapabili­ties.ThetopviewofthecontrolsystemisshowninFig.10-11whereicethermalstoragetanksareusedasmassblockssothatnoextramasswasintroduced.Themassesaresupportedbymulti-stagerubberbearingsintendedforreducingthecontrolenergyconsumedintheHMDandforinsuringsmoothmassmovements.应用HMD的一个案例。atop，在…的顶上；

hydraulicactuators

，液压执行器。10.4Active,HybridandSemi-activeControlSystems

10.4.2ActiveMassDamperSystemsDesignconstraints,suchasseverespacelimitations,canprecludetheuseofanHMDsystem.Suchisthecaseintheactivemassdamperoractivemassdriver(AMD)systemdesignedandinstalledintheKyobashiSeiwaBuildinginTokyoandtheNanjingCommunicationTowerinNanjing,China.InthecaseoftheNanjingCommunicationtower(Fig.10-15),numerousphysicalconstraintshadtobeaccountedfor

inthesystemdesignofthemassdamper.Thephysi­calsizeofthedamperwasconstrainedtoaring-shapedfloorareawithinnerandouterradiiof3and6.1m,respectively.Inaddition,thedamperwasbynecessityelevatedofftheflooronsteelsupportswithTeflonbear­ingstoallowfreeaccesstothefloorarea.Thefinalringdesignallowedthedampertomove±750mmfromitsrestposition.Simulationsindicatethatthisstrokeissufficienttocontrolthetower;however,agreaterstrokewouldallowsubstantiallymoreimprovementintheresponse.AMD应用的情况以及实际的案例。constraints，限制；

preclude，排除；

Teflonbear­ings，特氟龙轴承。10.4Active,HybridandSemi-activeControlSystems

ThefinaldesignoftheAMDisshowninFig.10-16,whichusesthreeservo-controlledhydraulicactuators,eachwithatotalstrokeof±1.50mandapeakcontrolforceof50kN.Theseactuatorsarearranged120°apartaroundthecircumferenceofthering.Theactuatorscon­trolthreedegreesoffreedom:twoorthogonallateraldirectionsofmotionandtorsionalrotation,whichisheldtozero.伺服控制液压执行器。stroke，行程；servo-controlledhydraulicactuators，10.4Active,HybridandSemi-activeControlSystems

10.4.3Semi-activeDamperSystemsControlstrategiesbasedonsemi-activedevicescom­binethebestfeaturesofbothpassiveandactivecontrolsystems.Thecloseattentionreceivedinthisareainrecentyearscanbeattributedtothefactthatsemi-activecontroldevicesoffertheadaptabilityofactivecontroldeviceswithoutrequiringtheassociatedlargepowersources.Infact,manycanoperateonbatterypower,whichiscriticalduringseismiceventswhenthemainpowersourcetothestructuremayfail.Inaddition,asstatedearlier,semi-activecontroldevicesdonothavethepotentialtodestabilize(intheboundedinput/boundedoutputsense)thestructuralsystem.Extensivestudieshaveindicatedthatappropriatelyimplementedsemi-activesystemsperformsignificantlybetterthanpassivedevicesandhavethepotentialtoachievethemajorityoftheperformanceoffullyactivesystems,thusallowingforthepossibilityofeffectiveresponsereductionduringawidearrayofdynamicloadingconditions.半主动阻尼系统的优点。beattributedto，归因于。10.4Active,HybridandSemi-activeControlSystems

Onemeansofachievingasemi-activedampingdeviceistouseacontrollable,electromechanical,variable-orificevalvetoaltertheresistancetoflowofaconventional