简介：

简介：在船体外板冷压成形过程中,由于回弹的存在,加工时必须反复修正才能使板材达到符合要求的形状,有限元数值模拟技术是解决回弹问题的有利工具.球形件是船体外板中比较常见的一种,本文针对球形面的船体板进行了回弹模拟,分析了板厚和不同曲率变化条件下对回弹的影响规律,为后续的利用回弹规律进行模具补偿提供依据.

简介：Mostoftheinvestigationsregardingfrictionstirwelding(FSW)ofaluminumalloyplateshavebeenlimitedtoabout5to6mmthickplates.InpriorworkconductedthevariousaspectsconcerningtheprocessparametersandtheFSWtoolgeometrywerestudiedutilizingfrictionstirweldingof12mmthickcommercialgradealuminumalloy.Twodifferentsimple-tomanufacturetoolgeometrieswereused.TheeffectofvaryingweldingparametersanddwelltimeofFSWtoolonmechanicalpropertiesandweldqualitywasexamined.Itwasobservedthatinordertoachieveadefectfreeweldingonsuchthickaluminumalloyplates,toolhavingtrapezoidalpingeometrywassuitable.Adequatetensilestrengthandductilitycanbeachievedutilizingacombinationofhightoolrotationalspeedofabout2000r/minandlowspeedofweldingaround28mm/min.Atverylowandhighdwelltimetheductilityofweldedjointsarereducedsignificantly.

简介：5月9日，国务院法制办公布了劳动合同法实施条例草案，并向社会各界广泛征求意见。草案共五章四十五条，包括总则、劳动合同的订立和履行、劳动合同的解除和终止、劳务派遣特别规定以及附则等内容，主要就劳动合同法贯彻实施中有关无固定期限劳动合同、经济补偿与赔偿金的关系、劳务派遣等方面的问题做了规定。此外，草案还对劳动关系的概念、劳动关系的中止、政府安置困难人员的公益性岗位的劳动合同等问题做了规定。

简介：摘要：通过选取幂函数作为复函数，运用复势函数法以及电场强度复数公式计算出两共焦抛物柱极板间的电势、电容和电场强度．

简介：2016年5月,IMO第96届海安会（MSC）所做MSC.406（96）号决议通过了国际海运危险货物规则第38-16套修正案。缔约国政府可自2017年1月1日起在自愿基础上部分或全部地运用有关新要求,自2018年1月1日起则要求强制性遵守。IMO第MSC.406（96）号决议包含了该规则第1册和第2册的修订全文。在许多变化中有几个尤其需要关注：添加了8个新的联合国编号（UN3527至UN3534）,其涵盖了聚酯树脂套件固体和液体的聚合物质以及发动机和机械。

简介：Acomplianttowerismodeledasapartiallydry,partiallytapered,dampedTimoshenkobeamwiththesuperstructuremodeledasaneccentrictipmass,andanon-classicaldampedboundaryatthebase.Thefoundationismodeledasacombinationofalinearspringandatorsionalspring,alongwithparallellinearandtorsionaldampers(Kelvin-Voigtmodel).Thesuperstructureaddstothekineticenergyofthesystemwithoutaffectingthepotentialenergy,therebyreducingthenaturalfrequencies.Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam,reducingitsnaturalfrequenciesfurther.Theemptyspacefactorduetothetruss-typestructureofthetowerisincluded.Theeffectofsheardeformationandrotaryinertiaareincludedinthevibrationanalysis;withthenon-uniformbeammode-shapesbeingaweightedsumoftheuniformbeammode-shapessatisfyingtheendcondition.TheweightsareevaluatedbytheRayleigh-Ritz(RR)method,andverifiedusingfiniteelementmethod(FEM).Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam.Kelvin-Voigtmodelofstructuraldampingisincluded.Apartofthestructurebeingunderwater,thevirtualaddedinertiaisincludedtocalculatethewetnaturalfrequencies.Aparametricstudyisdoneforvariousmagnitudesoftipmassandvariouslevelsofsubmergence.ThecomputationalefficiencyandaccuracyoftheRayleigh-Ritzmethod,ascomparedtotheFEA,hasbeendemonstrated.Theadvantageofusingclosed-formtrialfunctionsisclearlyseenintheefficacyofcalculatingthevariousenergycomponentsintheRRmethod.