Application of a wheel–rail contact model to railway dynamics in small radius curved tracks

Abstract

A multibody formulation with Cartesian coordinates is used to describe the kinematic structure of rigid bodies and joints that constitute the vehicle. A track parameterization methodology is implemented for the accurate description of the track spatial geometry emphasizing small radius curves, including its irregularities. A generic formulation is reviewed to determine, during the dynamic analysis, the contact forces that are generated in the wheel–rail interface. This contact model includes an algorithm that identifies the coordinates of the wheel–rail contact points, even for the most general three dimensional motion of the wheelset on the track. The proposed formulation can be applied to study the two points of contact scenario and, since the contact point in the wheel flange does not have to be located in the same plane as the contact point in the tread, it allows analyzing lead and lag flange contact configurations. An elastic force model that allows computing of the normal contact force in the wheel–rail interface, accounting for the energy loss during contact, is implemented and the tangential wheel–rail contact forces are calculated using one of three distinct creep force models: Kalker linear theory; Heuristic nonlinear method; Polach formulation. The methodologies proposed here are demonstrated by their application to the dynamic analysis of the boggie of a metro rail vehicle when negotiating a small radius curved track.