Vehicle-Track-Bridge Vertical System Coupled Vibration Analysis In The Case Of Uneven Settlement Of Pier And Abutment

In order to accord with the fast development of our country economy, the railway has carried on six times greatly enhancement of speed in nearly ten years. With raising of speed , the railway transportation ability is increased in large degree. Meanwhile, it makes especially important to study the question of vehicle-bridge dynamic interaction.In the case of uneven settlement of pier and abutment, 'fold angular' irregularity appears on the track. This kind of special irregularity must have a worse effect on operation safety and riding comfort. In order to effectively appraise the status of the vehicle, track and bridge, it is necessary to build vehicle-track-bridge coupling model.Many countries' scholars built the different vehicle-track-bridge coupling models according to the emphasis point of the questions, and drew many useful conclusions. This article builds secondary suspension and primary suspension vertical vehicle models according to D ' Alembert's principle, and according to the actual need of project question, some approximate hypotheses is carried on the vehicle. The rail vibration equation is established by mode coordinate method, which guarantees solution astringency and saves the computation resources through assigning mode number. Considering the different forms of the bridge structure section, the bridge model is established by finite element method.After vibration equations of the vehicle, the track and the bridge are built, the vehicle-track- bridge coupling model is built taking the wheel rail contact place as the threshold, and compile the computer procedure with FORTRAN language. This procedure uses the Newmark-βmethod iteration to obtain the solution, including dynamic performance of the bridge, such as deflection, the acceleration of bridge, and the vehicles vibration acceleration, the wheel track vertical force, reduction rate of wheel load, so as to appraisal the vehicle- bridge dynamic performance.This article builds 6 span 32 meters simply supported beams model for analyzing vehicle and bridge dynamic performance because of pier settlement. First the vehicle and bridge dynamic response is analyzed in the case of ordinary track irregularity, then in the case of different pier settlement quantity and different vehicle speed, and last in the case of combined action of two kinds of track irregularities. The result indicates, to 32 meters simply supported T beams, when "China star"passenger car's speed reaches 220 km/h, and the pier settlement quantity is 30 millimeters , the reduction rate of wheel load is 0.595 , which approaches 0.6 of criterion 's value. That is to say, the train is in a dangerous status through the bridge; However freight car's dynamic index is within safe range. Explain that the pier settlement quantity is mainly controlled by the passenger car.