Bifurcations and chaos in a model of a rolling railway wheelset

Abstract

In this paper we present the results of a numerical investigation of the dynamics of a model of a suspended railway wheelset in the speed range between 0 and 180 km h -1 . The wheel rolls on a straight and horizontal track unaffected by external torques. A nonlinear relation between the creepage and the creep forces in the ideal wheel rail contact point is used. The effect of flange contact is modelled by a very stiff spring with a dead band. The suspension elements have linear characteristics, and the wheel profile is assumed to be conical. All other parameters than the speed are kept constant. Both symmetric and asymmetric oscillations and chaotic motion are found. The results are presented as bifurcation diagrams, time series and Poincaré section plots. We apply bifurcation and path following routines to obtain the results. In the last chapter we examine one of the chaotic regions with the help of symbolic dynamics.