Masahito Adachi

Dynamics of track/wheel systems on high-speed vehicles

For high speed railway vehicles, we consider a vibiation of flexible track/wheel system It is very important to deal with the complex phenomena of high-speed vehicles that can be occurred in the vertical vibration of the system From a viewpoint of multibody dynamics, this kind of problem needs accurate analysis because the system includes mutual dynamic behaviors of rigid body and flexible body The simulation technique for the complex problems is also discussed We consider the high-speed translation, rail elasticity, elastic supports under the rail and contact rigidity Eigen value analysis is also completed to verify the mechanism of the coupled vertical vibration of the system

Analysis on Wheel Load Variation in Coupled Motion Between Running Wheel and Track with Irregularity

The decrease of wheel load variation is effective in enhancing stability, safety of high-speed train. In this paper, we conduct the simulation analysis on wheel load variation in order to figure out the mechanism of wheel load variation in consideration of track irregularity such as sine wave and to investigate the influence of the relation between unsprung mass and static wheel load. As a result, we figured out as follows : The wheel load variation at high speed increases according as the wheel speed because the vertical inertia force of wheel increases widely by high-speed running along the flexible rail with irregularity. If sleeper passing frequency and the irregularity passing frequency is close to the primary natural frequency of the wheel/rail system, the wheel load variation becomes larger. The decrease of wheel mass is very effective in decreasing the wheel load variation in comparison with the decrease of static wheel load.