The Theoretical Research And Simulation Analysis On Vibration System Of Vehicle-Turnout-Bridge Or Subgrade Coupling For Railway

In high-speed railway, bridges account for a high proportion, which are viaduct and long bridges, so the possibility of the turnout on the bridge is more than that on common railway. When the vehicle passing the turnout on the bridge, bridges produced large deformation and vibration, which can affect the smoothness of the track and then increased dramatically dynamic interaction between wheel and rail.so the security and stability of vehicle are decreased. In this paper, according to present research of vehicle-bridge coupled dynamics and turnout dynamics, the vehicle-turnout-bridge coupled dynamics is set up, which based on the vehicle-bridge coupled dynamics and turnout dynamics and taken turnout-bridge relation and wheel-rail relation as a link. Main research works of this paper are as follows:1. The vehicle-turnout-bridge coupled dynamics model is set up. Vehicle model with 31 degrees of freedom is set up. According to the characteristics of high-speed turnout, turnout dynamics model is set up by using finite element method. Based on Hamilton principle, bridge dynamics model is set up by using finite element method.2. The calculation method of wheel-rail contact geometry in the turnout area is given. Based on the elastic contact model, a calculation method of wheel-rail multi-point contact is introduced. This method can consider the elastic contact deformation between wheel and rail, which breaks traditional ideas that wheel and rail both are rigid body and wheel-rails both always keep in touch. According to the national norms of wheel and rail, the wheel and rail profile are described by some continuous curves.3. Based on elasticity theory, the calculation method of wheel-rail non-Hertz normal force is given. The comparison shows that the results by Hertz contact theory and non-Hertz theory are almost in agreement when the contact point is located at the middle of the wheel tread, while the results have obvious difference when the contact point is located at the junction of different radio acrs. The calculation results of non-Hertz are more real.4. The turnout–subgrade interaction principle was discussed. The area of the interaction of turnout and subgrade was discrete into the interaction of a series of points. The interaction points of track and subgrade was connected by linear springs and dampers. As long as vibration displacement and vibration velocity of various parts of the track were determined, the interaction force of turnout and subgrade was obtained.5. The turnout–bridge interaction principle was discussed. The area of the interaction of turnout and bridge was discrete into the interaction of a series of points. The interaction points of track and bridge was connected by linear springs and dampers. As long as vibration displacement and vibration velocity of various parts of the track and bridge were determined, the interaction force of turnout and bridge was obtained.6. The numerical integration method used in this paper is introduced, and the calculation program to solve the dynamic response of vehicle-turnout-bridge system is compiled by Fortran. The evaluation standard of vehicle, turnout and bridge is introduced.7. Using the vehicle-turnout-bridge coupled dynamic simulation program and through plenty of examples, the influence of turnout laying on the bridge or subgrade, the span and span number of continuous beam bridge, and vehicle running speed on the dynamic response of vehicles, turnout and bridge were analyzed. The rules of dynamic interaction were summarized:(1) When vehicle straight passes turnout on the subgrade, as the ballast stiffness increases, the dynamic response of derailment coefficient, reduction rate of wheel load, the lateral and vertical forces increase slightly, the lateral and vertical acceleration change little. Because speed is low, when vehicle laterally passes a turnout, the different ballast stiffness has little effect of the dynamic response of vehicle and turnout.(2) Because speed is low when vehicle laterally passes a turnout, the effect of coupling vibration between vehicle and bridge is not obvious. While vehicle straight through turnout on the bridge, dynamic effect of bridge has great influence, and various dynamic response of vehicle, turnout, bridge is greater than when vehicle through turnout on the subgrade.(3) With the increase of span of continue beam and the reduce of span number, the stiffness of bridge increases corresponding, which can result in more obvious effect of wheel-rail interaction and affect the security and stability of vehicle operation.(4) As the speed of train increases, coupling dynamic response of vehicle-turnout-bridge system also increases, especially above the speed of 300km/h.