The Influence Of The Alignment Change Of High Speed Railway Bridge On The Dynamic Performance Of Rail Vehicle Bridge System

In recent years,the high-speed railway construction in our country has developed rapidly,and the safe operation of high-speed trains has also attracted much attention.Many years of operation and management experience of high-speed railway at home and abroad shows that track irregularity is one of the important causes of derailment and overturning in the course of train running.At present,the railway line build many bridge to ensure the smoothness of track.However,there is the deformation of the girder bridge pier,uneven settlement and other issues.Therefore,this paper carried out the research on bridge alignment change on the dynamic performance of the vehicle track bridge system,evaluation of train operation in different conditions of security and stability,it has important significance for the safe operation of high-speed railway and high-speed railway bridge design security guide.Firstly,finite element model of a 32 meter span box girder was established based on the YUN Lianghe Bridge.The model was modified based on sensitivity analysis method In order to ensure the maximum deformation,the Japanese code is used as the box girder creep calculation model.The deformation process of the beam body was discussed according to the simulation results.The model predicted that girder residual deformation is 8.2mm after track laying.Then,Assuming that the track is in harmony with the deformation of the beam,a new track irregularity sample was generated by simulating the residual deformation of the box girder by the arc curve and superimposing it into the German low interference track spectrum.Secondly,a joint simulation model was established based on the principle of the train track bridge dynamic interaction,using the multi-body dynamics software UM and finite element software ANSYS through the UM FEM module.Among them,the EMU model took into account 8 sections,each carriage had 35 degrees of freedom,and the bridge model adopted ANSYS solid elements.Combined train and bridge dynamic response time diagram and peak value,compared the standard limit requirements and relevant calculation data of existing literature,vehicle rail bridge joint simulation model could accurately simulate the actual situation of the train bridge.Finally,the dynamic performance evaluation criteria of the rail bridge system were introduced,and 36 kinds of working conditions were set up to study the influence of the bridge alignment on the dynamic performance of the rail and bridge system.The results showed that the train safety and stability control indexes were the wheel load reduction rate and the vertical Spelling index.When the bridge alignment changes within 30 mm,it can guarantee the safety and smooth operation of the existing train.Then,the comprehensive effect of random track irregularity and the alignment change of the bridge was investigated under the condition of bridge arch 8.2mm,300 kilometers per hour.The results show that the vertical random irregularity of track has very significant and positive correlation with all the dynamic indexes of train and Bridge.The derailment coefficient is sensitive to the random amplitude of the two directions and is the control index of train operation safety under the given conditions.The train is in unsafe operation state when the transverse amplitude coefficient >1.5 and the vertical amplitude coefficient >2.0.