Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 08, 2024 - September 11, 2024
It is generally known that wheel flats tend to occur when the coefficient of friction between wheel and rail is small. However, the specific conditions under which wheel flats occur have not been clarified so far, since they tend to occur randomly. This paper proposes a method for evaluating wheel flat shape generated during braking of railway vehicles. Firstly, we developed a one-way coupled analysis method which combines vehicle dynamics analysis using commercial software, SIMPACK, and wheel/rail friction heat analysis under wheel-stick conditions. Secondly, the tangential longitudinal stress was calculated from the tangential contact force and contact ellipse calculated by SIMPACK, and the tangential yield stress of wheel steel is obtained from high-temperature tensile tests. Furthermore, the equilibrium conditions of the tangential stress and yield stress corresponding to the contact surface temperature are calculated as the contact ellipse of wheel/rail is gradually expanded, and its final shape is defined as the wheel flat shape. Finally, the validity of our proposed method is confirmed by comparing the results obtained by our proposed method with the measurement results for commercial vehicles.
