Nonlinear Wheelset Forces in Flange Contact—Part 1: Steady State Analysis and Numerical Results

A theoretical model for steady-state wheelset force/displacement relations in tread and flange contact is presented. The analysis includes nonlinear geometric constraints that characterize wheel/rail contact, creep forces in the contact plane due to wheel/rail differential velocities, limits on adhesion at each contact point, and equilibrium conditions applied to the wheelset body forces. Results are summarized as the resultant lateral force and yaw moment acting on the wheelset as functions of lateral position and yaw angle. The results of this analysis, verified experimentally in Part 2 of this paper, are important to the analysis of wheelset response to track inputs, curving performance, and wheelclimb derailment.