简介：Anewstochasticoptimalcontrolstrategyforrandomlyexcitedquasi-integrableHamiltoniansystemsusingmagneto-theological(MR)dampersisproposed.ThedynamicbehaviorofanMRdamperischaracterizedbytheBouc-Wenhystereticmodel.ThecontrolforceproducedbytheMRdamperisseparatedintoapassivepartincorporatedintheuncontrolledsystemandasemi-activeparttobedetermined.ThesystemcombiningtheBouc-Wenhystereticforceisconvertedintoanequivalentnon-hystereticnonlinearstochasticcontrolsystem.ThenItostochasticdifferentialequationsarederivedfromtheequivalentsystembyusingthestochasticaveragingmethod.Adynamicalprogrammingequationforthecontrolleddiffusionprocessesisestablishedbasedonthestochasticdynamicalprogrammingprinciple.Thenon-clippingnonlinearoptimalcontrollawisobtainedforacertainperformanceindexbyminimizingthedynamicalprogrammingequation.Finally,anexampleisgiventoillustratetheapplicationandeffectivenessoftheproposedcontrolstrategy.

简介：Theaimofthisresearchistocharacterizethedevelopmentoffatiguedamagebymeansofstress-strainhysteresis.Experimentswereconductedon14specimensmadeofcold-finishedunannealedAISI1018steel.Resultsdemonstratethatthemechanicalhysteresisloopareas,whenplottedasafunctionofthenumberofloadingcycles,showsignificantvariationsanddemonstratethethreeprincipalstagesconcerningtheprogressofthefatiguefailure—initialaccommodation,accretionofdamageandterminalfailure.ThesethreestagesoffatiguearemarkedbythetransitionsatcyclesN2andN3.ExperimentalresultsshowthatalthoughfatiguelifeNfrangesfrom2644cyclesto108992cycles,theratiosofN2/NfandN3/Nftendtobestable:N2/Nf=10.7%,N3/Nf=91.3%.

简介：Thispaperdescribesaseriesofexperimentalinvestigationsonseventeenspecimensofsteelreinforcedconcretespecialshaped(SRCSS)columnsunderlowcyclicreversedloadingusingparallelcrossheadequipment.NineT-shapedSRCcolumns,fourL-shapedSRCcolumnsandfour+-shapedSRCcolumnsweretestedtoexaminetheeffectsofshapesteelconfiguration,loadingangle,axialcompressiveratioandshear-spanratioonthebehavior(strength,stiffness,energydissipation,ductility,etc.)ofSRCSScolumnspecimens.Thefailuremodesandhystereticperformanceofallthespecimenswereobtainedinthetests.Testresultsdemonstratethattheshear-spanratioisthemainparameteraffectingthefailuremodesofSRCSScolumns.Thespecimenswithsmallshear-spanratioarepronetoshearfailure,andtheprimaryfailureplanesinSRCSScolumnsareparalleltotheloadingdirection.Asaresult,thereisasymmetrybetweenpositiveandnegativeloadingdirectionsinthehystereticcurvesoftheSRCSScolumns.Themajorityofdisplacementductilitycoefficientsforallthespecimensareover3.0,sothattheSRCSScolumnsdemonstrateabetterdeformationcapacity.Inaddition,theequivalentviscousdampingcoefficientsofallthespecimensaregreaterthan0.2,indicatingthattheseismicbehaviorofSRCSScolumnsisadequate.Finally,thesuperpositiontheorywasusedtocalculatethelimitsofaxialcompressiveratioforthespecimens,anditisfoundthatthetestaxialcompressiveratioisclosetoorsmallerthanthecalculatedaxialcompressiveratiolimit.

简介：获得评价能在结构的翻新的reprioritization帮助的一个精确条件的早结构的损坏鉴定安排以便保证结构的安全。现在，地震隔离技术被使用了在许多基础结构桥，等等，和这些非线性的hysteretic颤动隔离系统的健康条件例如大楼，收到了可观的注意。有效地基于颤动数据在颤动隔离系统检测结构的损坏，三种时间域分析技术，叫作适应扩大Kalman过滤器(AEKF)，适应顺序的非线性的最少平方的评价(ASNLSE)和适应二次的和平方错误(AQSSE)，被调查了。在这研究，这些分析技术以精确性，集中和效率被比较，为用通过基于受到ElCentro和科比地震刺激的一个孤立底的结构的模型的一系列实验室测试获得的试验性的数据的结构的损坏察觉。在追踪结构的损坏的AEKF，ASNLSE和AQSSE途径的能力被表明并且比较。

简介：Theinfluenceofthehystereticbehaviourinreactivesputteringwithapurealuminiumtargetinthepresenceofargonandoxygenplasmaontransmittanceandsurfacefreeenergyofaluminiumoxidefilmswasinvestigatedbyplasmaopticalemissionspectroscopytechnology.Theevolutionsofaluminium,andaluminiumoxideemissionlinesasfunctionsofoxygenflowrateatconstantpowerandpressurewerestudied.Asteeptransitionfromthemetallicsputteringtothecompoundsputteringwasobserveduponincreasingtheoxygenflowratefrom0.0SCCMtoabove2.0SCCM.Thenanoptimaldepositionzonewasobtainedthroughanalyzingthehystereticcurvesofaluminiumandaluminiumoxideemissionlines.TheevolutionofcrystalstructuresofsampleswasdiscernedbyX-raydiffractionspectradata.EnergydispersiveX-rayspectroscopydataalsodemonstratetherelationshipbetweenthechemicalcompositionsofaluminiumoxidefilmsandthehystereticbehaviour.Thefilmdepositedbetween1.5SCCMand2.0SCCMoxygenflowratedisplaysanoptimalandstoichiometicatomicratioofOtoAlandmassratioofOtoAl.ThechangesinthetransmittanceofsampleswerediscoveredtodependontheoxygenflowratebyUV-VIStransmittancespectra,andthechangesinsurfacefreeenergywerestudiedbycontactanglemeasurement.

简介：为P三角洲效果和增强的具体成员的hysteretic行为的修改精力平衡方程财务被导出。结构的部件的减少的hysteretic性质由于联合僵硬和力量，降级和拧的效果，和抑制的hysteretic被利用塑料精力和地震输入精力修正以一种简单方式考虑因素。有预先选择的收益机制，在无弹性的范围的结构的精力平衡被考虑。P三角洲效果被把严肃负担的外部工作加到相等的惯性力量的工作并且等同全部的外部工作到修改塑料精力在导出的方程包括。地震精力输入到多自由(MDOF)的度系统被使用形式的精力分解接近。基于精力的底砍系数借助于闲差事分析和有故事的不同数字的几个RC框架的非线性的时间历史(NLTH)分析被验证。框架的NLTH分析被与土耳其语的地震设计的相关要求编码的有弹性的设计加速光谱和圆满持续时间/振幅使用十放大地面运动兼容机的时间历史执行。在基于精力的底之间的观察关联砍力量系数和平均的底砍NLTH分析的力量系数在非线性的底的评价提供一颗合理信心砍由使用导出的方程的框架的力量能力。