简介：AftertheprogressivecollapseofRonanPointapartmentinUKin1968,intensiveresearchefforthadbeenspentondevelopingguidelinesfordesignofneworstrengtheningtheexistingstructurestopreventprogressivecollapse.However,onlyveryfewbuildingdesigncodesprovidesomerathergeneralguidance,nodetaileddesignrequirementisgiven.ProgressivecollapseoftheAlfredP.MurrahFederalbuildinginOklahomaCityandtheWorldTradeCentre(WTC)sparkedagaintremendousresearchinterestonprogressivecollapseofstructures.Recently,USDepartmentofDefence(DoD)andUSGeneralServiceAdministration(GSA)issuedguidelinesforstructureprogressivecollapseanalysis.Thesetwoguidelinesaremostcommonlyused,buttheiraccuracyisnotknown.Thispaperpresentsnumericalanalysisofprogressivecollapseofanexampleframestructuretoblastloads.TheDoDandGSAproceduresarealsousedtoanalysethesameexamplestructure.Numericalresultsarecomparedanddiscussed.Theaccuracyandtheapplicabilityofthetwodesignguidelinesareevaluated.

简介：Planechargeexplosiontechnique(PCET)isoneofthemajortechniquesfrequentlyusedinlarge-scaleblast-resistantstructuretests.AnFEMmodelwasestablished,whichcansimulatetheprocessofairreleasingfromtheblastcavity.Theeffectsofthechargedensity,theintervalofthechargestrip,thedistanceofthechargesfromthestructure,andthemassofbackfillsoilontheoverpressuresappliedonthetestedstructureswereanalyzedbytheFEMmodel.Thequantitativerelationshipsbetweenthepeakvalueandthedurationoftheoverpressureandtheabove-mentionedaffectingparameterswereestablished.Agreementbetweennumericalresultsandthetestdatawasobtained.

简介：在天津从Tanggu区域基于观察数据，一个back-propagationneural网络(BPNN)模型被介绍由于地下水的利用预言可能的陆地沉淀。根据在各种各样的假想抽取情形下面的模型评价，在Tanggu区域的陆地沉淀的模式被学习并且讨论。Tanggu的预言的平均背景陆地沉淀率是9.47mm/a。到陆地沉淀的含水土层的贡献的意义下降单位Ⅳ有序，Ⅲ，Ⅴ，Ⅱ。陆地沉淀趋于随全部的抽取率的增加败坏。

简介：Inthispaper,theproblemofParameterestimationinlineardelayedsystemsfromsampleddataistreated.Usingnumericalintegraloperation(NIO),anidentificationmodelwhichisparametrizeddirectlyinthelineardelayedsystempa-rametersisgot.Withtheleastsquare(LS)methodortheinstrumentalvariable(Ⅳ)method,therecursivealgorithmofparameterestimationisgiven.Theresultoftheillustratedexampleshowsthatthisalgorithmissimple,rapidandaccurrate.

简介：Theearthquake-resistantpropertyofreinforcedconcretemembersdependsontheinteractionbetweenreinforcingbarsandsurroundingconcretethroughbondtoalargedegree.Inthispaperageneralsystemaimedatdealingwiththefailureanalysisofreinforcedconcretecolumnsstrengthenedwithcarbon-fiber-reinforcedplastic(CFRP)sheetsincludingbond-slipoftheanchoredreinforcingbarsatthefootofthecolumnsispresented.Itisbasedontheyielddesigntheorywithamixedmodelingofthestructure,accordingtowhichtheconcretematerialistreatedasaclassicaltwo-dimensionalcontinuum,whereasthelongitudinalreinforcingbarsareregardedasone-dimensionalrodsincludingbond-slipatthefootofthecolumns.InshearreinforcedzonesboththeshearCFRPsheetsandtransversereinforcingbarsareincorporatedintheanalysisthroughahomogenizationprocedureandtheyareonlyintension.Theapproachisthenimplementednumericallybymeansofthefinite-elementformulation.Thenumericalprocedureproducesaccurateestimatesfortheloading-carryingcapacityoftheshearmemberstakenasanillustrativeapplicationbycorrelationwiththeexperimentalresults,sotheproposedapproachisvalid.

简介：Thispaperinvestigatesthestabilityandconvergenceofsomeknowndifferenceschemesforthenumericalsolutiontoheatconductionequationwithderivativeboundaryconditionsbythefictitiousdomainmethod.Thediscretevari-ablesatthefalsemeshpointsarefirstlyeliminatedfromthedifferenceschemesandthelocaltruncationerrorsarethenanalyzedindetail.Thestabilityandconvergenceoftheschemesareprovedbyenergymethod.Animprovementisproposedtoobtainbetterschemesovertheoriginalones.Severalnumericalexamplesandcomparisonswithotherschemesarepresented.

简介：Theidentificationofthecriticalinfrastructurehasshownthatthebuildcivilengineeringinfrastructureisalmostinvolvedeverywhere,evenwiththeIT-infrastructure.Therefore,thepassivesafetyofstructuresisdemanded.Securityassociationshaveanalysedthatmostassaultscamealongwithexplosionandimpactscenarios,whichamountin80%ofassaults.Consequently,thesearetheextraordinaryloadsthestructureshavetobeplannedanddesignedfor.Tocarryoutsuchanengineeringjob,theengineerhastobeeducatedinmultipledisciplinesasphysics,materialscience,continuummechanics,numericalmechanics,testing,structuralengineeringandrelatedspecificfieldsaswavepropagationetc.Inthispaperwewillconcentrateonthesubjectsofnumericalsimulationandtesting.

简介：Thispaperprovidesanumericalanalysismodelofunsteadyheattrans-ferinpiston-linersetofaninternalcombustionengine.Themodelsimulatestheun-steadyheattransferprocessamongthecombustionmixture,pistonset,lubricantfilm,linerandcoolantinawholeenginecycle,andcanpredictthetemperaturefluc-tuationanddistributiononpistoncrown,innersurfaceofliner,pistonringandthelubricantfilm.Acomputerprogramisdevelopedtocalculatetheunsteadyheattrans-ferprocessofpiston-linersysteminawater-cooleddieselengine.

简介：AhomogeneoustheoreticalmodelisdevelopedtopredicttheperformanceofR22andR290inadiabaticcapillarytubes.Themodelisbasedonconservationequationsofmass,momentumandenergy.Metastablebothliquidandtwo-phaseflowregionsareconsideredinthemodel.Inmetastabletwo-phaseregion,superheatedliquidisintroducedintothemetastablemixtureviscosityandtwomethodsarepresentedtoevaluateit.Themodelisvalidatedbycomparingthepredictedpressureandtemperatureprofileandmassflowratewithseveralinvestigators′experimentaldataofR22andoneofitsalternativesR290reportedinliterature.Allofthepredictedmassflowratesarewithin±8%ofmeasuredvalues.Comparisonsarealsomadebetweenthepresentmodelandotherinvestigators′modelsorsizingcorrelation.Themodelcanbeusedfordesignorsimulationcalculationofadiabaticcapillarytubes.

简介：CharacteristicsofR22anditsnewalternativerefrigerantR290flowingthroughadiabaticcapillarytubesareinvestigatedbasedonthehomogeneousmodel.Extensiveflowvariablesalongtubelengthsuchaspressure,temperature,viscosity,velocity,Reynoldsnumber,frictionfactorandvaporqualityetcarecomparedbetweenthetwofluidsunderthesameoperatingcondition.Twocasesareconsidered,namely,eitherthesametubelengthorthesamemassflowrateasinletcondition.TheresultsshowthatthemassflowrateinthecapillarytubeofR290is40%lowerthanthatofR22duetothedifferencesofphysicalpropertiesbetweenthetwofluids.Further,aparametricanalysisisperformedanditappearsthateffectsofgeometricandthermodynamicparametersonmassflowrateofR290areweakerthanthatofR22.Whenthecondensingtemperatureisincreasedfrom40℃to50℃,themassflowrateforR22isincreasedby16%,whiletheincreasingrateforR290is13%.