Stability of a flexible wheelset for high speed rail vehicles with constant and varying parameters

The stability of an elastic wheelset coupled with a torsional spring and a torsional damper is presented in this paper. With flexible elements between two wheels, the advantages of both rigid and independently rotating wheel (IRW) systems may be obtained. Previous studies indicated that the flexible elements will affect the vehicle dynamic behavior and an optimal parameters may improve the system performance. However, those studies were limited to constant wheel/rail geometry as the wheelset rolls along the track. In this paper, it is intended to determine the critical speed regions thus to reduce the potential for hunting. The critical velocity of constant and time-varying models is presented. The variation in conicity is assumed to be periodic thus the Floquet stability concept may be employed. The computation of the state-transition matrix is based on a Runge-Kutta algorithm.