Abstract
Parametric instability of a wheel moving at a constant speed on a railway track is discussed. For this purpose, this paper presents an analytical formulation in which the damping is considered in rail supports. Since the dynamic behavior of a railway track depends on the rail axial load arising from the temperature change, this effect is also taken into account in the present mathematical model. Through numerical analyses, it is found that the eigenvalue which characterizes the quasi-steady-state dynamic reaction of the moving wheel and track is translated toward the positive imaginary number under the existence of damping. The range of unstable velocity is then narrowed by the introduction of dissipation into the track structure. Moreover, the critical damping at which the instability zone vanishes is obtained. Although the compressional rail stress reduces the instability speed, its contribution to the critical damping is insignificant.
