Research On Structural Seismic Response Considering The Influence Of Train-bridge Coupling Vibration

In recent years,high-speed railway has become the main way for Chinese residents to travel.By 2025,the mileage of high-speed railways will reach 38,000 kilometers.Bridges on high-speed railways account for a large proportion.China is a country with frequent earthquakes.The probability of encountering earthq uakes when trains run on bridges is significantly increased.Therefore,it is of practical significance to study the coupled vibration of vehicles under earthquakes.This thesis is based on ANSYS for the study of vehicle-bridge coupling problems.The main research contents and results are as follows:(1)The equation of motion of the simplified theoretical model of vehicle-bridge interaction is derived.The numerical solution of the equation of motion is obtained based on the Newmark method.The ANSYS simulation of the simplified theoretical model of vehicle-bridge interaction is realized based on the displacement coupling method.By comparing the numerical solution of the model with the ANSYS simulation solution,the feasibility of using ANSYS to study the vehicle-bridge coupled vibration problem is verified.(2)Based on ANSYS software,a 17-DOF two-dimensional vehicle model was established using MASS21 unit,MPC184 unit and COMBIN14 unit,a three-span continuous rigid frame bridge finite element model was established using BEAM189 unit and MPC184 unit.The first 9 modes of the vehicle model and the first 6 modes of the bridge finite element model are extracted using the Block Lanczos method.(3)According to the specific site conditions,three seismic waves were selected based on the design response spectrum,and the time-history analysis of the bridge under the multiple earthquakes was carried out.The calculation results show that the components of the bridge are in the elastic working stage during the sm all earthquake;The vertical seismic response of bridge is independent of the longitudinal seismic response of bridge.When performing the section design of the beam body,the vertical earthquake action should be included.When performing the section design of the pier,the vertical seismic response of bridge can be ignored.(4)Based on ANSYS,the coupled simulation of vehicle model and bridge finite element model is carried out,and the response of vehicle-bridge coupling system under different working conditions such as different vehicle speed,different axle weight,different pier height and considering seismic action is calculated.The calculation results show that the vertical displacement of the vehicle body decreases with the increase of the speed,the vertical acceleration of the vehicle body,the vertical displacement of the bridge and the vertical acceleration of the bridge increase with the increase of the speed;The response of the system increases as the axle weight increases;The vertical displacement of the vehicle body,the vertical acceleration of the vehicle body and the vertical displacement of the bridge increase with the increase of the height of the pier.The vertical acceleration of the bridge decreases with the increase of the height of the pier.When considering the grouping of vehicles,the dynamic response characteristics of the bridges exhibit obvious periodic components.When the earthquake and the train load act on the bridge,the train load will amplify the response of the bridge structure.When designing the bridge structure,it is necessary to incorporate the influence of the vehicle-bridge coupling vibration to ensure the safety of the structure.