Study On Coupled Vibration Of High Speed Train-Track-Bridge System Under Wave Loads

The development of modern railway is inseparable from the foundation of bridge construction.Railway bridges can greatly promote the development of regional economic prosperity.However,cross-sea railway bridges in coastal areas of China often face the impact of wave loads,and large-span bridges tend to show greater flexibility in design,which makes wave motion have obvious dynamic effects on bridges and trains.At present,there are few dynamic response results and operational analysis of trains and bridges under the combined action of wave loads.Therefore,the research on vehicle-bridge coupling dynamic response under wave loads needs to be further discussed and analyzed.Based on the fluid dynamics theory and vehicle-bridge coupling dynamics theory,a railway bridge is taken as the research object in this paper.The numerical wave flume is established to obtain the wave force under different working conditions.The dynamic response analysis of the bridge model under wave load is carried out in Ansys finite element software,and the substructure analysis of the bridge and track model is carried out to obtain the flexible body file.Then the Simpack multi-body dynamics software is used to establish the vehicle-track-bridge coupling model.Finally,the dynamic response results of the vehicle-track-bridge coupling model under wave load are discussed and analyzed.This paper mainly obtains the following results :(1)Based on the Stokes fifth-order wave and Jonswap wave spectrum,the three-dimensional numerical wave flume model of the bridge tower in deep water environment was established by using Fluent computational fluid dynamics software.The wave force under different working conditions was simulated,and the correctness of the numerical flume construction was verified by adjusting the height change diagram of the wave surface.Secondly,the velocity field and pressure field under wave telemotion were analyzed,and it was found that the wave attached to the bridge tower changed significantly.At the same time,the wave force changed periodically with time,and the wave force increased gradually with the increase of wave height.(2)The finite element model of the sea-crossing bridge was established by Ansys software,and the modal analysis was carried out.The results of the first 10 orders of self-vibration characteristics show that the middle of the main span of the bridge and the top of the bridge tower are the main positions that need attention in the dynamic response.Secondly,four wave conditions are formulated,and the dynamic responses of the bridge under four wave conditions are analyzed.The results show that the acceleration response results and displacement response results at different positions also gradually increase with the increase of wave height,and the dynamic response of the tower top is larger than that of the mid-span response of the main span,the secondary side span and the side span response in turn.(3)A single section train with 35 degrees of freedom was built by Simpack dynamics software,and then a multi-group train model was built by grouping it.The flexible track method was used to import the flexible track into the dynamics software and coupled with the multi-pack train model.Four types of track irregularities were simulated according to the German low disturbance power spectrum,and finally the results of the train running at250km/h speed were calculated to obtain the safety and comfort of the train,and the results were analyzed according to the high speed rail code,and the results showed that the train running safety and comfort could meet the requirements.(4)Simpack software was used to illustrate the relationship between the main degree of freedom selection and the frequency of the flexible body of the bridge;secondly,a coupled vehicle-rail-bridge dynamics model under wave loading was established;the calculation results of the vehicle-rail-bridge dynamics model under the combined effect of vehicle speed and wave show that the bridge dynamic response is influenced by the size of the wave height,the larger the wave height,the dynamic response increases subsequently,and the larger the vehicle speed,the larger the growth rate.The derailment coefficient and wheel pair transverse force grow faster in the operational safety results of the train subsystem,and the acceleration of the train increases significantly with the increase of vehicle speed and wave load,and passengers will have obvious discomfort.