Research On Simulation For Lateral Vibration And Structures Suitable For High Speed Of Railway Bridges

In modern society with the development in economy and the improvement on people'sstandard of living, the more comfortable and more efficient transportaion means is required.Furthermore, in order to increase the railway's competitive capability to that of freeway andair transport, the train speed has been increased drastically in resent years. The speed ofpassenger trains has been increased stag by stag from less than l00 km/h to l20. l40.l60km/h or even 200km/h, and the speed of freight trains has been increased stage by stagefrom 50 km/h tO 60. 80. l00 km/h. At the same time, special railway lines for high-speedpassenger trains (200-300km/h) are being constructed. In our country bridges of existingrailway tracks are almost simple PC T-type girders and I-type steel girders of 20-40 spanlength which have been designed under the speed of l20km/h and without the considerationof running quality However, When unloaded freight trains pass through the above bridgeswith the speed higher than 60km/h, there is serious lateral resonance aroused from the bridge,especially for simple I-type Steel girder with a maximum lateral displacement of l2mm. AndWhen the passenger trains pass through the above bridges with the speed higher than l60km/h,the amplitude of the bridge's lateral vibration also exceeds the reference value ofspecifications. So, how to simulate the dynamic response of vehicle-track -bridge system toresearch the fitfol renovation method of existing railway bridges to meet the need of therunning quality of trains by increased speed and to research the structures suitable forconstruction high speed railway are our important task.On accoullt of the urgent need of the solution of problems of existing railway bridgesand high-speed railway bridges, in this paper the following problems are researched:Firstly, the dynamic test and the numerical simulation are carried through for theYangLouSi bridge(L=32m simple I-type steel girder). The finite element method is employedin establishing the calculation model for the vehicle-track-bridge joint structure system, andMSC/DYTRAN is adopted in the calculation of contact force between wheel and rail and inanalyzing the structure system dynamic response. The speed of vehicle and the railirregularities of different grade are input. The explicit method is adopted and in every timestep the grid-point accelerations. grid-point velocities and displacements. element strainf＆tCS,CleffiCllt StfCSSCS slid CICffiCllt foFCCS t gfld polfltS sfC C8lCu18tCd．Flflslly hC ChsflgCS Ofaccele血ions,displacements and forces with time are obtained．The running safety Isevaluated by the wheel load reduction rate and derailment ratio and the riding comfort isevaluated with the咒celeMions of vehicles．Then the esults of calculatlolls e comparedwith the test values andthe randomlclty of＊thelclty lateral vibration amplitude and the forcedfrequency of＊thency two re ye0 slml你 which verify the credltablllty of＊theablllty analysis method． Moreovec the simplified analysis model ofslmulatingthe sn毗e motion as h忆raf forcechanging accoding to coslne w uue In cwle Is put fo fiNlN加．nd with this model the sn毗motlon frsrequencles that can Induce the h卜fsl esonance of the bud驴e o讪ined．Thecalculated f6sults e cons卜比＊w讪the iC砒d one,so It has p fnfntlcal meaning on quicklydetermining the sn劝"motion frequencies that can Induce the 血曰alresonance of the bridgethrough simplified analysis． To m1n河1e】atera！resonance o75e slmp！e Itwe stee！glder,6asd on enefgydlsslpatlontheom伽 vlscoelastlc damper device of32m simple N仰 st6el glder isdesigned．Then the damper device Is installed in the YangLOusi brd驴 and the duamic 5 gyetect Is conducted．yhe ie一主一一一回L大一言土d fCsultS manifest that the vlscoel一自白色一一主一一注Ic damper玉匡奎自二甲一一晖stl...