Research On Dynamic Performance And Safety Of Vehicle-bridge-track System For Long-span High Speed Railway Continuous Steel Truss Bridge

With the continuous development and improvement of high-speed railway construction technology and bridge design level,high-speed railway mileage,train running speed and high-speed railway bridge span also continue to grow.The safety of long-span high-speed railway bridge track train coupling system under high-speed train operation has naturally attracted wide attention of relevant researchers.In order to study the safety of high-speed railway long-span bridge and running train system,the main research contents of this paper are shown as follows:First of all,take a high-speed railway five span continuous steel truss bridge as example,this paper established a 128m+180m×3+128m=796m ANSYS multi-scale full bridge finite element model,then according to the spectrum analysis of the measured acceleration data of the bridge health monitoring system,the natural vibration frequency of the actual bridge could be obtained by the method of peak recognition.Based on the sensitivity finite element model correction method to reduce the difference between the service bridge and the theoretical model,and the theoretical model can well represent the service state of the actual bridge.Secondly,the German low interference track spectrum for the 250km/h high-speed railway was generated by the Universal Mechanism(UM),a multi-body dynamics software.At the same time,combined with the interaction principle of bridge-track-train dynamic coupling system,UM and ANSYS were used for the simulation of bridge-track-train system.According to the time-history curve and maximum value of train vibration response in the system,the representativeness of theoretical train model was confirmed by comparing the safety limit requirements.Through filtering the measured Angle and strain sensor data,and comparing with the dynamic response time history curve of the bridge obtained from the vehicle-rail-bridge joint simulation model,it is found that the bridge-track-train coupling system established can represent the service situation of the actual system from the macro and micro.Finally,the dynamic performance evaluation system of bridge-track-train coupling system was introduced,and the influence mechanism of train speed,train axle load,train formation,bridge structure damping and random track irregularity amplitude on the vibration response of train and bridge was discussed respectively.According to the evaluation system,the safety evaluation of bridge and train under various operating conditions was obtained.The results show that the resonance speed range of the coupling vibration between the bridge and the train is 230 km/h to 250 km/h;The faster the train speed and the greater the axle load,the smaller the damping of the bridge structure and the greater the amplitude of the track irregularity,the more significant the vibration response of the whole vehicle bridge coupling system;The increase of the number of train formation will reduce the peak value of bridge vertical deflection;Considering the influence of the above factors on the dynamic amplification factor of the vertical displacement of the bridge under the condition of variable speed,the appropriate damping ratio can effectively reduce the dynamic amplification factor and play a good role in damping vibration and protecting the track alignment;Train safety and stability are greatly affected by train running speed and track irregularity amplitude.It is necessary to strengthen track irregularity monitoring and control the train running at the design speed of 250 km/h.