ge,additionalnetworksofsubsystemscanbeaddedtothemodelthatareexcitedbythevelocityofparticularsusbsystemsofthemainnetwork.Thebridgebearingsandpiersarenotimportantforthenoiseradiation.Forthetrack,therailsupportstiffnessisanimportantparameter.Thecombinedroughnessofthewheelandrailrunningsurfacesexcitesthewheelandrailintovibrationaccordingtotheirdynamicproperties.Modelsfortherollingnoiseemittedbythewheelandtrackarewellestablished[,].ThewayinwhichthetrackisassumedtotransmitenergytotheSEAmodelofthebridgeisanimportantaspectofthecalculation.Forthecurrentbridge,amodeloftherailcoupledviaacon-tinuousspring-mass-springsupporttothelongitudinalbeamofthebridgehasbeenuseduptotherail-on-sleeperresonancefrequency.Abovethisfrequencytheforce毕业设计外文文献及译文fromthetrackisassumedtodrivethelocalinputmobilityofthelongitudinalbeam.ThelatterisbasedonanapproximateformulaforanI-sectionbeam[].Thesoundpoweriscalculatedfromthevibrationve赫兹频率带噪声降低情况,尽管光谱测量结果比预测更顺利。
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