A Technique for Validating a Multibody Wheel/Rail Contact Algorithm

Abstract

In this paper, a specialized steady state formulation is developed in order to validate the results obtained using multibody wheel/rail two-point contact algorithms developed at the University of Illinois at Chicago. In the specialized formulation, the wheel set is assumed to have three points of contact with the rail. The steady state curving behavior of the wheel set is examined using this specialized formulation. The balanced steady state curving behavior in which the centrifugal force is equal to the lateral component of the gravity force can be obtained as a special case of the specialized steady state formulation developed in this investigation. No derailment analysis or scenarios are considered in this paper in order to validate the results of both the constraint and elastic contact formulations. The results of the simple specialized formulation are compared with the results of the multibody inverse and forward dynamics approaches. In the inverse dynamics, approach it is assumed that the wheel set will maintain three points of contact with the rail. The inverse dynamics formulation model is conceptually different from the specialized steady state formulation since in the inverse dynamics all the degrees of freedom are specified. In the multibody forward dynamics method, no assumptions are made with regard to the existence of the flange contact.