简介:装载的风是为控制大跨度的房顶结构的设计的最重要的负担之一。相等的静态的风负担,能通常瞄准决定特定的回答,被结构的设计者广泛地使用。为对多反应适用的相等的静态的风负担的一个方法在这份报纸被建议。相应于特别山峰回答的一个修改loadresponse-关联(纵向冗余码校验)方法被介绍,并且类似算法实现了因为组反应被描述。算法的主要想法是二回答能被放进一个组如果一回答的价值接近另外的反应的,当结构受到瞄准另外的反应的相等的静态的风负担时。基于修改纵向冗余码校验,组织反应方法被提出到装载的构造等价物静电干扰风。这种技术能同时为一些组织回答复制山峰回答。验证它的计算精确性,方法被用于实际大跨度的房顶结构。计算结果看那在一样的组的回答的类似什么时候高,有高精确性的相等的静态的风负担和相等的静电干扰的合理大小弯屈分发能被完成。
简介:Asimplifiedmultisupportresponsespectrummethodispresented.Thestructuralresponseisasumoftwocomponentsofastructurewithafirstnaturalperiodlessthan2s.Thefirstcomponentisthepseudostaticresponsecausedbytheinconsistentmotionsofthestructuralsupports,andthesecondisthestructuraldynamicresponsetogroundmotionaccelerations.Thismethodisformallyconsistentwiththeclassicalresponsespectrummethod,andtheeffectsofmultisupportexcitationareconsideredforanymodalresponsespectrumormodalsuperposition.Iftheseismicinputsateachsupportarethesame,thesupportdisplacementscausedbythepseudostaticresponsebecomerigidbodydisplacements.Theresponsespectruminthecaseofmultisupportexcitationsthenreducestothatforuniformexcitations.Inotherwords,thismultisupportresponsespectrummethodisamodificationandextensionoftheexistingresponsespectrummethodunderuniformexcitation.Moreover,mostofthecoherencycoefficientsinthisformulationaresimplifiedbyapproximatingthegroundmotionexcitationaswhitenoise.Theresultsindicatethatthissimplificationcanreducethecalculationtimewhilemaintainingaccuracy.Furthermore,theinternalforcesobtainedbythemultisupportresponsespectrummethodarecomparedwiththoseproducedbythetraditionalresponsespectrummethodintwocasestudiesofexistinglong-spanstructures.Becausetheeffectsofinconsistentsupportdisplacementsarenotconsideredinthetraditionalresponsespectrummethod,thevaluesofinternalforcesnearthesupportsareunderestimated.Theseregionsareimportantpotentialfailurepointsanddeservespecialattentionintheseismicdesignofreticulatedstructures.
简介:Twoaspectsofanewmethod,whichcanbeusedforseismiczoning,areintroducedinthispaper.Ontheonehand,theapproachtoestimatebvalueandannualactivityrateproposedbyKijkoandSellevollneedstousetheearthquakecatalogue.Theexistingearthquakecataloguecontainsbothhistoricalandrecentinstrumentaldatasetsanditisinadequatetouseonlyonepart.Combiningthelargenumberofhistoricaleventswithrecentcompleterecordsandtakingthemagnitudeuncertaintyintoaccount,Kijko’smethodgivesthemaximumlikelihoodestimationofbvalueandannualactivityrate,whichmightbemorerealistic.Ontheotherhand,thismethodconsidersthesourcezoneboundaryuncertaintyinseismichazardanalysis,whichmeanstheearthquakeactivityrateacrossaboundaryofasourcezonechangessmoothlyinsteadofabruptlyandavoidstoolargeagradientinthecalculatedresults.
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简介:Theconceptofstatevectorstemsfromstatisticalphysics,whereitisusuallyusedtodescribetheevolutionofacontinuumfieldinitswayofcoarse-graining.Inthispaper,thestatevectorisemployedtodepicttheevolutionofseismieityquantitatively,andsomeinterestingresultsarepresented.Theauthorsinvestigatedsomefamousearthquakecases(e.g.,theHaiehengearthquake,theTangshanearthquake,thewestKuulunMountainsearthquake,etc.)andfoundthatthestatevectorsevidentlychangepriortotheoccurrenceoflargeearthquakes.Thusitisbelievedthatthestatevectorcanbeusedasakindofprecursortopredictlargeearthquakes.
简介:Inthispaper,thespatiallinearitymethodisappliedtosyntheticalprocessingofprecursorydatafromdifferentstationsanddifferentdisciplines.Thenewcharacteristicvalue(a)obtainedcandescribethewholeprecursoryfield.Theauthorspresenttheformulasforcalculatingspatiallinearity.Furthermore,thespatiallinearitymethodisappliedtoprocessingofgeoelectricalresistivityandgroundwaterleveldatafrom1970to1994inNorthChina.Theresultsshowthatthenewcharacteristicvalue(a)coulddetecttheanomaly1yearbeforemoderatelystrongearthquakes.
简介:Ithasbeenproventhattheimplicitmethodusedtosolvethevibrationequationcanbetransformedintoanexplicitmethod,whichiscalledtheconcomitantexplicitmethod.Theconstantaccelerationmethod'sconcomitantexplicitmethodwasusedasanexampleandisdescribedindetailinthispaper.Therelationshipbetweentheimplicitmethodandexplicitmethodisdefined,whichprovidessomeguidanceabouthowtocreateanewexplicitmethodthathashighprecisionandcomputationalefficiency.
简介:Afrequencyandspatialdomaindecompositionmethod(FSDD)foroperationalmodalanalysis(OMA)ispresentedinthispaper,whichisanextensionofthecomplexmodeindicatorfunction(CMIF)methodforexperimentalmodalanalysis(EMA).ThetheoreticalbackgroundoftheFSDDmethodisclarified.Singularvaluedecompositionisadoptedtoseparatethesignalspacefromthenoisespace.Finally,anenhancedpowerspectrumdensity(PSD)isproposedtoobtainmoreaccuratemodalparametersbycurvefittinginthefrequencydomain.Moreover,asimulationcaseandanapplicationcaseareusedtovalidatethismethod.
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简介:Theoptimalmatrixmethodandoptimalelementalmethodusedtoupdatefiniteelementmodelsmaynotprovideaccurateresults.Thissituationoccurswhenthetestmodalmodelisincomplete,asisoftenthecaseinpractice.Animprovedoptimalelementalmethodispresentedthatdefinesanewobjectivefunction,andasabyproduct,circumventstheneedformassnormalizedmodalshapes,whicharealsonotreadilyavailableinpractice.Tosolvethegroupofnonlinearequationscreatedbytheimprovedoptimalmethod,theLagrangemultipliermethodandMatlabfunctionfminconareemployed.Todealwithactualcomplexstructures,thefloat-encodinggeneticalgorithm(FGA)isintroducedtoenhancethecapabilityoftheimprovedmethod.Twoexamples,a7-degreeoffreedom(DOF)mass-springsystemanda53-DOFplanarframe,respectively,areupdatedusingtheimprovedmethod.Thcexampleresultsdemonstratetheadvantagesoftheimprovedmethodoverexistingoptimalmethods,andshowthatthegeneticalgorithmisaneffectivewaytoupdatethemodelsusedforactualcomplexstructures.
简介:ResearchonnonlinearR/SmethodanditspplicationinearthquakepredictionBi-QuanWANG(王碧泉);Han-MingHUANG(黄汉明);Hong-ShunFAN(范洪顺);Chuen...