简介:交通安全,人命关天。尤其在春运期间,由于车流量、客流量的剧增,道路交通管理工作任务更加艰巨。据预测,今年春运期间,全国公路客流量预计比2002年春运增加4%,将达到16.5亿万人次。因此,今年春运道路交通管理工作十分繁忙,责任更加重大。如何确保春运期间的道路交通安全,成为各地公安交通管理部门的当务之急。2003年的春运工作,从元月17日开始至2月25日结束,历时40天。春运在即,各地公安交通管理部门的春运工作如何开展?春运期间他们又将采取哪些具体措施?元月9日,皖、沪、苏、浙、闽、赣、鲁、豫、鄂9个省(市)的交、巡警“老总”们聚会在安徽省合肥市外商国际俱乐部,召开了一次春运交通安全协调会议。
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.