学科分类
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10 个结果
  • 简介:Tworocksampleswithdifferentstructuresandmaterialsweredeformedunderabiaxialloadingsystem,andmulti-pointstrainmeasurementswereperformedforeachsample.ThedistributionofstrainanomaliesduringthedeformationandtheinstabilityprocesswereanalyzedbyusingCvvalueputforwardbyWANGXiao-qingandCHENXue-zhong,etal,aparametertodescribetheheterogeneousdistributionofearthquakeprecursors,soastoexaminethemethodofCvvalueandtoexploreitsphysicalmeaningexperimentally.TheresultshowsthatthechangeofCvvalueiscorrelatedtothechangeofdeformationcharacteristicsandisaneffectiveparametertodescribetheheterogeneityofprecursordistribution.Cvvalueincreasesfirstlyandthendecreasesbeforetheinstability,andtheinstabilityoccurswhenCvvaluedecreasestothelevelbeforeincreasing.ThisindicatesthatCvvaluemaybeausefulparameterforearthquakeprediction.

  • 标签: rock mechanical experiment STRAIN field EARTHQUAKE
  • 简介:光谱表示方法(SRM)广泛地被用来模仿空间地变化的地面运动。这研究基于根分解集中于SRM的近似途径,它能改进模拟的效率。近似途径的精确性可以被三个因素影响:为分解的矩阵,为插值的频率插值节点和元素的分发。这条途径的精确性上的这些因素的影响被检验,下列结论被得出。SRM基于十字的根分解比SRM基于落后连贯矩阵的根分解展出更大的精确性光谱矩阵。节点在这研究建议了的频率插值的相等的精力分发是比有相等的间距的相反的木髓更有效的。为插值的元素没在精确性上有许多效果,因此因为它从一个计算效率观点是不太复杂的,分解矩阵的元素的插值被推荐。

  • 标签: 矩阵分解 空间变化 SRM 基础 模拟 地震动
  • 简介:在这篇论文,一个新奇参量的基于模型的分解方法为变化时间的结构监视的结构的健康被建议。为这个目的,先进功能系列的时间依赖者汽车回归的动人的一般水准(FS-TARMA)技术被用来估计在参量的信号分解计划使用的参数和革新变化。另外,一个唯一的特征抽取和减小方法基于分解信号,已知的同样潜伏的部件(LC),被建议。为了在实验室评估建议方法,数字模拟和试验性的研究的效率,在变化时间的结构上被进行,在损坏的各种各样的类型被介绍的地方。模糊专家系统(FES)被用作一个分类工具当时,证明建议方法成功地识别不同结构的条件与另外的方法相比基于非减少、平常的特征抽取。

  • 标签: 参数模型 信号分解 特征提取 模糊专家系统
  • 简介:Evolutionarycomputationbasedontheideaofbiologicevolutionisonetypeofglobaloptimizationalgorithmthatusesself-adaptation,self-organizationandrandomsearchingtosolveoptimizationproblems.Theevolutionary-simplexalgorithmisintroducedinthispaper.Itcontainsfloatingencodingwhichcombinestheevolutionarycomputationandthesimplexalgorithmtoovcrcomctheproblemsencounteredinthegeneticalgorithmandevolutionarystrategymethods.Numericalcxpcrimcntsarcperformedusingseventypicalfunctionstoverifythealgorithm.Aninverseanalysismethodtoidentifystructuralphysicalparametersbasedonincompletedynamicresponsesobtainedfromtheanalysisinthetimedomainisprcscntcdbyusingtheevolutionary-simplexalgorithm.Themodalevolutionary-simplexalgorithmconvertedfromthetimedomaintothemodaldomainisproposedtoimprovetheinverseefficiency.Numericalcalculationsfora50-DOFsystemshowthatwhcncomparedwithothermethods,theevolutionary-simplexalgorithmoffersadvantagesofhighprecision,cfficientsearchingability,strongabilitytoresistnoise,independenceofinitialvalue,andgoodadaptationtoincompleteinformationconditions.

  • 标签: MODAL paramcter PHYSICAL PARAMETER INVERSE analysis
  • 简介:为有在出现在所有团中的控制输入隧道和参数无常的时间延期的电镀物品水力的激活的结构的系统的一个类的柔韧的活跃颤动控制的问题,抑制并且僵硬矩阵在这份报纸被调查。由介绍一个线性变化参数,首先,非线性的系统被描述为变化的一个线性参数(LPV)模型。基于这个LPV模型,第二,为asymptotically要稳定的系统的一个基于LMI的条件被推出。由解决这些LMI,一个参数依赖者控制器为与骚乱变细的规定水平稳定的closedloop系统被建立。条件也被扩大到不明确的案例。最后,一些数字模拟表明建议控制器的令人满意的表演。

  • 标签: 线性变参数 结构系统 液压驱动 控制器 振动衰减 电动
  • 简介:Thispaperpresentsacopulatechniquetodeveloptime-variantseismicfragilitycurvesforcorrodedbridgesatthesystemlevelandconsiderstherealistictime-varyingdependenceamongcomponentseismicdemands.Basedonmaterialdeteriorationmechanismsandincrementaldynamicanalysis,thetime-evolvingseismicdemandsofcomponentswereobtainedintheformofmarginalprobabilitydistributions.Thetime-varyingdependencesamongbridgecomponentswerethencapturedwiththebestfittingcopulafunction,whichwasselectedfromthecommonlyusedcopulaclassesbytheempiricaldistributionbasedanalysismethod.Thesystemtime-variantfragilitycurvesatdifferentdamagestatesweredevelopedandtheeffectsoftime-varyingdependencesamongcomponentsonthebridgesystemfragilitywereinvestigated.Theresultsindicatethetime-varyingdependenceamongcomponentssignificantlyaffectsthetime-variantfragilityofthebridgesystem.Thecopulatechniquecapturesthenonlineardependenceamongcomponentseismicdemandsaccuratelyandeasilybyseparatingthemarginaldistributionsandthedependenceamongthem.

  • 标签: system FRAGILITY chloride corrosion TIME-VARYING DEPENDENCE
  • 简介:Incorporatingrateandstatefrictionlaws,stabilityoflinearlystable(i.e.,withstiffnessgreaterthanthecriticalvalue)spring-slidersystemssubjectedtotriggeringperturbationswasanalyzedundervariablenormalstresscondition,andcomparisonwasmadebetweenourresultsandthatoffixednormalstresscasesrevealedinpreviousstudies.Forsystemsassociatedwiththesliplaw,thecriticalmagnitudeofratestepsfortriggeringunstableslipsarefoundtohaveasimilarpatterntothefixednormalstresscase,andthecriticalvelocitystepsscalewitha/(b-a)whenk=kcrforbothcases.Therate-stepboundariesforthevariablenormalstresscasesarerevealedtobelowerthanthefixednormalstresscaseby7%–16%forarelativelylargea=0.56with(b-a)/arangingfrom0.25to1,indicatingeasiertriggeringunderthevariablenormalstressconditionwithratesteps.Thedifferencebetweenfixedandvariablenormalstresscasesdecreaseswhentheavalueissmaller.Inthesamesliplaw-typesystems,criticaldisplacementstotriggerinstabilityarerevealedtobelittleaffectedbythevariablenormalstresscondition.WhenkCkcr(V*),aspring-slidersystemwiththeslownesslawismuchmorestablethanwiththesliplaw,suggestingthattheslownesslawfitsexperimentaldatabetterwhenasinglestatevariableisadopted.Instick-slipmotions,thevariablenormalstresscasehaslargerstressdropsthantheconstantnormalstresscase.Thevariablenormalstresshaslittleeffectontherangeofslipvelocityinsystemsassociatedwiththeslownesslaw,whereassystemsassociatedwiththesliplawhaveaslowestslipvelocityimmenselysmallerthanthefixednormalstresscase,by*10ordersofmagnitude.

  • 标签: 滑块系统 正应力 粘滑运动 稳定性 弹簧 速率
  • 简介:这个地点和结构的参数无常的动态效果的考虑被标准在大多数国家为核电厂(NPP)要求。抗地震的标准提供二个基本方法分析参数无常。手工地直接处理计算地板反应系列(皇家学会会员)确定的途径珍视是第一个方法。第二个方法是执行概率统计的FRS的分析根据蒙特卡罗方法结果。二个方法能仅仅反映不明确的参数的全面效果,并且结果不能为某个参数影响和贡献被屏蔽。在这研究,基于NPP的地板反应系列的动态分析,为各种各样的不明确的参数的估计的影响的一个全面索引被介绍并且推荐,包括关联系数,回归斜坡系数和旋风秋千。在NPP地震标准补偿指导的缺乏,建议方法能有效地被用来从敏感,尖酸和统计秋千的方面评估各种各样的参数的贡献关联。最后,例子被提供从系统、直觉的观点验证指示物的集合,例如NPP的皇家学会会员的结构参数和贡献的影响的无常。这个索引对参数的不同类型敏感,它为评估为NPP要求的抗地震的参数提供一种新技术。

  • 标签: 参数不确定性 楼层反应谱 评估方法 结构层 核电厂 概率统计分析
  • 简介:Thispaperaddressesthefreetransversevibrationsofthinsimplysupportednonhomogeneousisotropicrectangularplatesofbilinearlyvaryingthicknesswithelasticallyrestrainededgesagainstrotation.TheGram-Schmidtprocesshasbeenusedtogeneratetwo-dimensionalboundarycharacteristicorthogonalpolynomials,whichhavebeenusedintheRayleigh-Ritzmethodtostudytheproblem.Thelowestthreefrequencieshavebeencomputedforvariousvaluesofnonhomogeneousparameters,thicknessparameters,aspectratioandflexibilityparameters.Acomparisonoftheresultswiththoseavailableintheliteraturehasbeenmade.Three-dimensionalmodeshapesforthespecifiedplatehavebeenpresented.

  • 标签: NONHOMOGENEOUS RECTANGULAR bilinearly VARYING thickness elastically