Host: The Japan Society of Mechanical Engineers
Name : Dynamics and Design Conference 2021
Date : September 13, 2021 - September 17, 2021
One of the problems of high-speed railways is the phenomenon of hunting, in which the car body and bogies vibrate significantly from side to side during high-speed running. It is very important to understand the mechanism of the hunting because it not only makes the ride uncomfortable but also causes track damage and wear. In order to understand the mechanism of hunting, we model and carried numerical simulation of a two-axle bogie with a real tread geometry in a high-speed railway. In this study, the running stability of the bogie is evaluated by determining the critical speed of the two-axle bogie. When the initial lateral displacements are given as disturbances, the critical speed differs depending on the initial displacement, and the larger the initial displacement, the lower the critical speed. The reasons are presented as follows: the first reason is that the equivalent conicity of the wheel increases with large amplitude. Second, due to the nonlinear characteristics of the creep force, the creep force does not increase linearly even when the creep rate increases. Moreover, the results show that the hunting becomes a limit cycle above a certain initial displacement when given a speed below the critical speed determined by the eigenvalue analysis, and that the hunting becomes a limit cycle regardless of the amplitude when given a speed above the critical speed determined by the eigenvalue analysis.
