Analysis Of Dynamic Characteristics For Railway Vehicle System

With the increase of speed in recent years, the dynamic action between the vehicle parts and the wheel-rail has become significant, which can lead to a more serious dynamic problem. So it is very important to study the stability of high-speed train. This thesis is aimed at the stability and curving performance of the high-speed railway vehicle. The contents are listed as follows:In the first chapter, the development process of high-speed train, vehicle dynamics, lateral stability, bifurcation and curving performance, recent developments and achievements are all summarized. Then, the main work is illustrated.In the second chapter, the model of the railway vehicle stability is studied. Then modeling methods to the multi-rigid-body and the calculation of wheel-rail creep force, normal contact force, flange force, suspension force are all stated. Finally, the simplify of shock absorber and the time domain numerical simulation method are also represented.In the third chapter, a 17-degree model of the lateral stability is established. The bifurcation point and the periodical solution are obtained by using the numerical method. The linear critical speed and nonlinear critical speed are obtained. There exists complicated motion form when the speed is higher than the critical speed, including single period, double period, multi-period and chaos motions. The lateral and longitudinal rigidity value of the primary suspension has a great influence on the critical speed, the nonlinear critical speed usually increases first and keeps a constant value later when the rigidity value increases. The vertical rigidity and resistance value of the primary suspension have little influence on nonlinear critical speed. The nonlinear critical speed usually increases when the lateral and longitudinal rigidity value of the secondary suspension increases. the nonlinear critical speed of the system will be the biggest when the lateral resistance value of the secondary suspension increases to a certain value. The vertical rigidity and resistance value of the secondary suspension have little influence on nonlinear critical speed.In the fourth chapter, a 50-degree model of the vehicle by using the multi-body dynamics software UM is established. The nonlinear critical speed when the vehicle running on a straight track is obtained. The longitudinal, lateral and vertical rigidity value of the axle beam node has a great influence on the nonlinear critical speed, so is the rigidity and resistance value of the anti-yawing dampers. But, the longitudinal, lateral and vertical rigidity value of the traction rod have little influence on it. It is safe and the stability index is belong to the optimal level when vehicle running on the minimum radius of curved track. Finally, the influence of track parameters on the dynamic performance of vehicle is studied.In the fifth chapter, a 56-degree model of the vehicle seeing the left and right rail as rigid bodies is established. The nonlinear critical of this system can be obtained. The lateral, vertical rigidity and resistance value of the cushion has a great influence on the stability of system. Then the curve-passing ability of the railway vehicle is analyzed. We know that it is safe and the stability index is belong to the optimal level when the vehicle runs on the 4500 m radius of curved track with 200~250km/h speeds. With cure radius value in less and super high state, the dynamic response of the vehicle model having rigid rails and massless rails can be compared, knowing that the vibration of track has a great influence on the stability of system.