简介:"结构调整关系企业的生存空间,关系企业新的利润来源,关系企业的发展方向,是一个决定企业是否长期有饭吃、是否有较高利润回报的问题,对于企业发展是个重大的战略问题,必须坚定不移地持续推进。"中国铁建总裁张宗言《关于企业持续健康发展的几个重大问题》文章中以上的这段文字,科学的揭示机构调整对于建筑施工企业,特别是对中国铁建生存发展的重要。我们必须清醒的认识到,产业结构构成了国民经济诸产业间相互联系、相互依赖、相互制约的对应关系,其结构的配置必然与国民经济的发展和国家产业政策的调整同步。建筑施工企业产业结构调整也将成为长期的任务。从战略层面讲,它事关我们企业可持续发展的战略定位;从战术层面讲,它为我们在应对日益复杂多变的市场,提升企业综合管控能力提出了许多新课题、新要求。
简介:Theobjectiveofthisworkistoanalysefatiguereliabilityofdeckstructuressubjectedtocorrelatedcrackgrowth.Thestressintensityfactorsofthecorrelatedcracksareobtainedbyfiniteelementanalysisandbasedonwhichthegeometrycorrectionfunctionsarederived.TheMonteCarlosimulationsareappliedtopredictthestatisticaldescriptorsofcorrelatedcracksbasedontheParis-Erdoganequation.Aprobabilisticmodelofcrackgrowthasafunctionoftimeisusedtoanalysethefatiguereliabilityofdeckstructuresaccountingforthecrackpropagationcorrelation.Adeckstructureismodelledasaseriessystemofstiffenedpanels,whereastiffenedpanelisregardedasaparallelsystemcomposedofplatesandarelongitudinal.Ithasbeenproventhatthemethoddevelopedherecanbeconvenientlyappliedtoperformthefatiguereliabilityassessmentofstructuressubjectedtocorrelatedcrackgrowth.
简介:Inthisstudy,thepassageofwavesthroughpilegroupswithdifferentarrangementsisinvestigatedusingathree-dimensional(3D)numericalmodel.Forthesimulations,wavesofthreedifferentheightsof36,58,and81mm,afixedperiodof0.88s,andafixedwavelengthof1.128mwereused.Tosimulatethewavesandflowpatternthroughthepiles,Reynolds-averagedNavier–Stokes(RANS)equationsoffluidmotionweresolvedbasedonthefinitevolumemethod(FVM).Pilesweredefinedasobstaclesintherectangulardomainusingthefractionalarea/volumeobstaclerepresentation(FAVOR)method.Thevolume-of-fluid(VOF)andre-normalizationgroup(RNG)methodswereusedtosimulatethefreesurfaceandturbulencephenomenon,respectively.Byperformingdifferentnumericalsimulations,theeffectofcoastalpilearrangementsonwavepatternwasstudiedandwascomparedwithexistingexperimentaldata,andanacceptableagreementwasachieved.