《土木工程專業(yè)英語 第2版》 課件 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

綜述減震構(gòu)件的類型10.2BasicPrinciples

公式原理10.3PassiveEnergyDissipation被動系統(tǒng)MetallicdampersFrictiondamperVEdampersViscousfluiddampersTunedmassdampersTunedliquiddampers10.4Active,HybridandSemi-activeControlSystems

主動、混合、半主動系統(tǒng)Hybrid

mass

damper

systemsActivemassdampersystemsSemi-active

damper

systemsSemi-activeControllableFluidDampers10.1Introduction

Inrecentyears,

innovative

meansofenhancingstruc-turalfunctionalityandsafetyagainstnaturalandman-madehazards

havebeeninvariousstagesofresearchanddevelopment.Byandlarge,theycanbegroupedintothreebroadareasasshowninTable10-1.1).baseisolation;2).passiveenergydissipation；3).activecontrol.抵御自然和人為災(zāi)害提高結(jié)構(gòu)功能和安全性的方法：三大類innovative創(chuàng)新，革新；stages

階段；byandlarge大體上，總的來說；10.1Introduction

Ofthethree,baseisolationcannowbeconsideredamorematuretechnologywithwiderapplicationsascom-paredwiththeothertwo.Passiveenergydissipationsystemsencompass

arangeofmaterialsanddevicesforenhancingdamping,stiff-nessandstrength,andcanbeusedbothforseismichaz-ardmitigationandforrehabilitation

ofagingordeficientstructures.Ingeneral,suchsystemsarecharacterizedbytheircapabilitytoenhanceenergydissipationinthestructuralsystemsinwhichtheyareinstalled.Thesedevicesgenerallyoperateonprinciplessuchasfrictionalsliding,yieldingofmetals,phasetransform-ationinmetals,deformationofviscoelastic(VE)solidsorfluidsandfluidorificing.基礎(chǔ)隔震相對成熟和應(yīng)用；被動控制包括很多材料和設(shè)備（提高阻尼、剛度、強度）。同時用于減少地震災(zāi)害和修復(fù)年久破損結(jié)構(gòu)。encompass

，圍繞，包圍；

mitigation，緩解，減輕；rehabilitation，修復(fù)；dificient，有缺陷的；

viscoelastic，粘彈性；orifice，孔口；onprinciples，基于原理；

phasetransformationinmetals，金屬相變。10.1Introduction

Active/hybrid/semi-activecontrolsystemsareforcedeliverydevicesintegratedwithreal-timeprocessingevaluators/controllersandsensorswithinthestructure.Theyactsimultaneouslywiththehazardousexcitationtoprovideenhancedstructuralbehaviorforimprovedserviceandsafety.Researchtodatehasalsoreachedthestagewhereactivesystemshavebeeninstalledinfull-scalestructuresforseismichazardmitigation.主動、混合、半主動控制實時評估和控制傳感器目前可安裝在全尺結(jié)構(gòu)simultaneously

，同時；research

to

date

，迄今為止的研究。10.1Introduction

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

技術(shù)評估+結(jié)構(gòu)控制體系的基本概念、種類、優(yōu)缺點。state-of-the-artandstate-of-the-practice，發(fā)展水平和實踐；

inthecontextof，在……情況下，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.主動控制系統(tǒng)的組成。algorithm，算法；actuators，執(zhí)行器，激勵器。10.2Basic

Principles

Whenonlythestructuralresponsevariablesaremeas-ured,thecontrolconfigurationisreferredtoasfeedbackcontrolsincethestructuralresponseiscontinuallymoni-toredandthisinformationisusedtomakecontinualcor-rectionstotheappliedcontrolforces.Afeedforwardcontrolresultswhenthecontrolforcesareregulatedonlybythemeasuredexcitation,whichcanbeachieved,

forearthquakeinputs,bymeasuringaccelerationsatthestructuralbase.Inthecasewheretheinformationonboththeresponsequantitiesandexcitationareutilizedforcontroldesign,thetermfeedback-feedforwardcon-trolisused.句式比較繁雜。反饋控制的機理。be

referredtoas，被稱為，視為；

feedforward，前饋控制。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,whereasincreasedstructuralsafetymaybetheobjectivedur-ingseveredynamicloading.主動控制的其他優(yōu)點。cite，舉例;byandlarge，總的來說。10.2Basic

Principles

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

stabilityisguaranteed.Semi-activecontroldevicesareoftenviewedascontrollablepassivedevices.Asidebenefitofhybridandsemi-activecontrolsys-temsisthat,inthecaseofapowerfailure,thepassivecomponentsofthecontrolstilloffersomedegreeofpro-tection,unlikeafullyactivecontrolsystem.混合控制和半主動控制的特點和優(yōu)勢portion，部分；

imply，意味著；bound，邊界。10.2Basic

Principles

10.3Passive

Energy

Dissipation

DiscussionspresentedbelowarecenteredaroundsomeofthemorecommondeviceswhichhavefoundapplicationsinPED.10.3.1

MetallicYieldDampersOneoftheeffectivemechanismsavailableforthedis-sipationofenergyinputtoastructurefromanearth-quakeisthroughinelasticdeformationofmetals.ManyofthesedevicesusemildsteelplateswithtriangularorXshapessothatyieldingisspreadalmostuniformlythroughoutthematerial.AtypicalX-shapedplatedamperorADAS(addeddampingandstiffness)deviceisshowninFig.10-2.Otherconfigurationsofsteelyieldingdevices,usedmostlyinJapan,includebendingtypeofhoneycomband

slit

dampersandshearpaneltype.Othermaterials,suchasleadandshape-memoryalloys,havealsobeenevaluated.Someparticularlydesirablefeaturesofthesedevicesaretheirstablehystereticbehavior,low-cyclefatigueproperty,longtermreliability,andrelativeinsensitivitytoenvironmentaltemperature.金屬屈服阻尼器mildsteelplates，低碳鋼板；

uniformly，均勻，一體；

honeycomb

，蜂窩，彎曲型蜂窩；slit，狹縫；

alloys，合金。10.3Passive

Energy

Dissipation

Aftergainingconfidenceintheirperformancebasedprimarilyonexperimentalevidence,implementationofmetallicdevicesinfull-scalestructureshastakenplace.TheearliestimplementationsofmetallicdampersinstructuralsystemsoccurredinNewZealandandJapan.Anumberoftheseinterestingapplicationsarereported.MorerecentapplicationsincludetheuseofADASdampersintheseismicupgradeofexistingbuild-ingsinMexicoandintheUSA.TheseismicupgradeprojectdiscussedininvolvestheretrofitofaWellsFargoBankbuildinginSanFrancisco,CA.Thebuildingisatwo-storynonductileconcreteframestructureoriginallyconstructedin1967andsubsequentlydamagedinthe1989LomaPrietaearthquake.AtotalofsevenADASdeviceswereemployed,eachwithayieldforceof150kips.Bothlinearandnonlinearanalyseswereusedintheretrofitdesignprocess.ADAS在SanFrancisco的應(yīng)用。kips

，千磅。10.3Passive

Energy

Dissipation

Avariationofthedevicesdescribedabovebutoperatingonthesamemetallicyieldingprincipleisthetension/compressionyieldingbrace,alsocalledtheunbondedbrace,whichhasfoundapplicationsinJapanandtheUSA.AsshowninFig.10-4,anunbondedbraceisabracingmemberconsistingofacoresteelplateencasedinaconcrete-filledsteeltube.Aspecialcoatingisprovidedbetweenthecoreplateandconcreteinordertoreducefriction.Thecoresteelplateprovidesstableenergydissipationbyyieldingunderreversedaxialload-ing,whilethesurroundingconcrete-filledsteeltuberesistscompressionbuckling.介紹了金屬屈服構(gòu)件的一種變體。unbonded

，無粘結(jié)的；encased，被包住10.3Passive

Energy

Dissipation

10.3.2

Friction

DampersFrictiondampersutilizethemechanismofsolidfric-tion

thatdevelopsbetweentwosolidbodies

slidingrela-tivetooneanothertoprovidethedesiredenergydissi-pation.Severaltypesoffrictiondampershavebeendevelopedforthepurposeofimprovingseismicresponseofstructures.AnexampleofsuchadeviceisdepictedinFig.10-5.Duringcyclicloading,themechanismenforcesslippageinbothtensileandcompressivedirections.Gen-erally,frictiondevicesgeneraterectangularhystereticloopssimilartothecharacteristicsofCoulombfriction.Afterahystereticrestoringforcemodelhasbeenvali-datedforaparticulardevice,itcanbereadilyincorpor-atedintoanoverallstructuralanalysis.摩擦阻尼器的原理。enforces，施加；vali-dated，有效；coulombfriction

，庫倫摩擦10.3Passive

Energy

Dissipation

10.3.3

ViscoelasticDampersViscoelastic(VE)materialsusedinstructuralapplicationsareusuallycopolymersorglassysubstancesthatdissi-pateenergythroughsheardeformation.AtypicalVEdamper,whichconsistsofVElayersbondedwithsteelplates,isshowninFig.10-6.Whenmountedinastructure,sheardeformationandhenceenergydissipationtakesplacewhenstructuralvibrationinducesrelativemotionbetweentheoutersteelflangesandthecenterplates.Sig-nificantadvancesinresearchanddevelopmentofVEdampers,particularlyforseismicapplications,havebeenmadeinrecentyearsthroughanalysesandexperimentaltests.粘彈性阻尼器的原理。viscoelastic

，粘彈性；copolymers

，共聚物；mounted，安裝。10.3Passive

Energy

Dissipation

10.3.3

ViscoelasticDampersAseismicretrofitprojectusingVEdampersbeganin1993forthe13-storySantaClaraCountybuildinginSanJose,CA.Situatedinahighseismicriskregion,thebuildingwasbuiltin1976.Itisca64minheightandnearlysquareinplan,with51m×51montypicalupperfloors.Theexteriorcladdingconsistsoffull-heightglazingontwosidesandmetalsidingontheothertwosides.Theexteriorcladding,however,provideslittleresistancetostructuraldrift.Theequivalentviscousdampinginthefundamentalmodewas<1%ofcritical.對結(jié)構(gòu)的抗震升級（加固）

cladding，包層，電鍍；critical，臨界值；glazing，玻璃；10.3Passive

Energy

Dissipation

10.3.4

Viscous

fluid

dampersTheviscousfluid(VF)devicesdevelopedrecentlyincludeviscouswallsandVFdampers.Theviscouswall,developedbySumitomoConstructionCompany,con-sistsofaplatemovinginathinsteelcasefilledwithhighlyVF.TheVFdamper,widelyusedinthemilitaryandaerospaceindustryformanyyears,hasrecentlybeenadaptedforstructuralapplicationsincivilengineering.AVFdampergenerallyconsistsofapistonwithinadamperhousingfilledwithacompoundofsiliconeorsimilartypeofoil,andthepistonmaycontainanumberofsmallorificesthroughwhichthefluidmaypassfromonesideofthepistontotheother.

Thus,VFdam-persdissipateenergythroughthemovementofapistoninahighly

VFbasedontheconceptoffluidorificing.粘質(zhì)液體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,numericalandexperimentalstud-ieshavebeencarriedouttoexaminetheeffectivenessofTMDsinreducingseismicresponseofstructures.ItisnotedthatapassiveTMDscanonlybetunedtoasinglestructuralfrequency.Whilethefirst-moderesponseofaMDOFstructurewithTMDscanbesubstantiallyreduced,thehighermoderesponsemayinfactincreaseasthenumberofstoriesincreases.Forearthquake-typeexci-tations,theresponsereductionislargeforresonantgroundmotionsanddiminishesasthedominantfre-quencyofthegroundmotiongetsfurtherawayfromthestructure’snaturalfrequencytowhichtheTMDsistuned.調(diào)諧質(zhì)量阻尼器的減震特點。betuned

，調(diào)諧；resonant，共振。10.3Passive

Energy

Dissipation

10.3.6

TunedLiquidDampers

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

freeofmaintenanceandeaseoffrequencytuning.TheTLDapplicationshavetakenplaceprimarilyinJapanforcontrollingwind-inducedvibration.ExamplesofTLD-controlledstructuresincludeairporttowersandtallbuildings.調(diào)諧液體阻尼器的機理和應(yīng)用特點及優(yōu)勢sloshing

，沖擊，晃蕩；

suppressing，抑制；

virtually

，幾乎。10.4Active,HybridandSemi-activeControlSystems

Therapidgrowthofresearchinterestanddevelopmentofactive/hybridandsemi-activestructuralcontrolsys-temsisinpartduetoseveralcoordinated

researchefforts,largelyinJapanandtheUSA,markedbyaseriesofmilestoneslistedinTable10-2.Indeed,themostchal-lengingaspectofactivecontrolresearchincivilengin-eeringisthefactthatitisanintegrationofanumberofdiversedisciplines,

someofwhicharenotwithinthedomainoftraditionalcivilengineering.Theseincludecomputerscience,dataprocessing,controltheory,materialscience,sensingtechnology,aswellasstochas-ticprocesses,structuraldynamics,andwindandearth-quakeengineering.Thesecoordinatedeffortshavefacili-tatedcollaborativeresearcheffortsamongresearchersfromdiversebackgroundsandacceleratedtheresearch-to-implementationprocessasoneseestoday.主動控制是多學(xué)科綜合的研究領(lǐng)域coordinated

，協(xié)同；

disciplines，學(xué)科；

stochas-tic

，隨機的。10.4Active,HybridandSemi-activeControlSystems

Asalludedtoearlier,thedevelopmentofactive,hybrid,andsemi-activecontrolsystemshasreachedthestageoffull-scaleapplicationstoactualstructures.Otherthantheseinstallationsinbuildingstructuresandtow-ers,mostofwhichareinJapan,

15bridgetowershaveemployedactivesystemsduringerectioninaddition.Mostofthesefull-scalesystemshavebeensub-jectedtoactualwindforcesandgroundmotionsandtheirobservedperformancesprovideinvaluableinfor-mationintermsof:1)validatinganalyticalandsimulationproceduresusedtopredictactualsystemperformance2)verifyingcomplexelectronic-digital-servohydraulicsystemsunderactualloadingconditions.3)verifyingcapabilityofthesesystemstooperateorshutdownunderprescribedconditions.主動系統(tǒng)觀測到的數(shù)據(jù)的用途。Erection，建造；prescribed，規(guī)定的；asalludedtoearlier，如前文所述；

electronic-digital-servohydraulicsystems，數(shù)電液壓系統(tǒng)。10.4Active,HybridandSemi-activeControlSystems

Describedbelowareseveralofthesesystemstogether,insomecases,withtheirobservedperformances.Alsoaddressedareseveralpracticalissuesinconnectionwithactualstructuralapplicationsofthesesystems.10.4.1HybridMassDamperSystemsTheHMDisthemostcommoncontroldeviceemployedinfull-scalecivilengineeringapplications.HMDisacombinationofapassiveTMDsandanactivecontrolactuator.TheabilityofthisdevicetoreducestructuralresponsesreliesmainlyonthenaturalmotionoftheTMDs.TheforcesfromthecontrolactuatorareemployedtoincreasetheefficiencyoftheHMDandtoincreaseitsrobustnesstochangesinthedynamiccharacteristicsofthestructure.TheenergyandforcesrequiredtooperateatypicalHMDarefarlessthanthoseassociatedwithafullyAMPsystemofcom-parableperformance.下文重點講述系統(tǒng)、應(yīng)用的表現(xiàn)和連接方面的問題。HMD的工作特點和優(yōu)點。com-parable，可比的。10.4Active,HybridandSemi-activeControlSystems

AnexampleofsuchanapplicationistheHMDsysteminstalledintheSendagayaINTESbuildinginTokyoin1991.AsshowninFig.10-10,theHMDwasinstalledatopthe11thfloorandconsistsoftwomassestocontroltransverseandtorsionalmotionsofthestructure,whilehydraulicactuatorsprovidetheactivecontrolcapabili-ties.ThetopviewofthecontrolsystemisshowninFig.10-11whereicethermalstoragetanksareusedasmassblockssothatnoextramasswasintroduced.Themassesaresupportedbymulti-stagerubberbearingsintendedforreducingthecontrolenergyconsumedintheHMDandforinsuringsmoothmassmovements.應(yīng)用HMD的一個案例。atop，在…的頂上；

hydraulicactuators

，液壓執(zhí)行器。10.4Active,HybridandSemi-activeControlSystems

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

inthesystemdesignofthemassdamper.Thephysi-calsizeofthedamperwasconstrainedtoaring-shapedfloorareawithinnerandouterradiiof3and6.1m,respectively.Inaddition,thedamperwasbynecessityelevatedofftheflooronsteelsupportswithTeflonbear-ingstoallowfreeaccesstothefloorarea.Thefinalringdesignallowedthedampertomove±750mmfromitsrestposition.Simulationsindicatethatthisstrokeissufficienttocontrolthetower;however,agreaterstrokewouldallowsubstantiallymoreimprovementintheresponse.AMD應(yīng)用的情況以及實際的案例。constraints，限制；

preclude，排除；

Teflonbear-ings，特氟龍軸承。10.4Active,HybridandSemi-activeControlSystems

ThefinaldesignoftheAMDisshowninFig.10-16,whichusesthreeservo-controlledhydraulicactuators,eachwithatotalstrokeof±1.50mandapeakcontrolforceof50kN.Theseactuatorsarearranged120°apartaroundthecircumferenceofthering.Theactuatorscon-trolthreedegreesoffreedom:twoorthogonallateraldirectionsofmotionandtorsionalrotation,whichisheldtozero.伺服控制液壓執(zhí)行器。stroke，行程；servo-controlledhydraulicactuators，10.4Active,HybridandSemi-activeControlSystems

10.4.3Semi-activeDamperSystemsControlstrategiesbasedonsemi-activedevicescom-binethebestfeaturesofbothpassiveandactivecontrolsystems.Thecloseattentionreceivedinthisareainrecentyearscanbeattributedtothefactthatsemi-activecontroldevicesoffertheadaptabilityofactivecontroldeviceswithoutrequiringtheassociatedlargepowersources.Infact,manycanoperateonbatterypower,whichiscriticalduringseismiceventswhenthemainpowersourcetothestructuremayfail.Inaddition,asstatedearlier,semi-activecontroldevicesdonothavethepotentialtodestabilize(intheboundedinput/boundedoutputsense)thestructuralsystem.Extensivestudieshaveindicatedthatappropriatelyimplementedsemi-activesystemsperformsignificantlybetterthanpassivedevicesandhavethepotentialtoachievethemajorityoftheperformanceoffullyactivesystems,thusallowingforthepossibilityofeffectiveresponsereductionduringawidearrayofdynamicloadingconditions.半主動阻尼系統(tǒng)的優(yōu)點。beattributedto，歸因于。10.4Active,HybridandSemi-activeControlSystems

Onemeansofachievingasemi-activedampingdeviceistouseacontrollable,electromechanical,variable-orificevalvetoaltertheresistancetoflowofaconventional