Effect of elasto-plasticity on the creep force characteristics and the ă railway vehicle stability
Résumé
To determine the tangential forces at the wheel-rail contact level, the ă linear coefficients of stiffness provided by Kalker's theory are used in ă many dynamic codes for the different contact models simulated. These ă creep coefficients are exposed in reality to many reducing parameters ă like roughness, surface contamination and third body layer. They also ă can't take into account the elasto-plastic behavior of the bodies in ă contact. In this paper, a three dimensional finite element model is ă developed to study the wheel-rail rolling contact. The elastic solution ă was compared to Kalker's theories and the effect of elasto-plasticity on ă the creep force characteristics was studied. It is found that the ă elasto-plastic behavior reduces the creep coefficients in the ă longitudinal and the lateral direction. The reduced coefficients of ă stiffness are assessed from this model and their influence on railway ă vehicle stability is checked. The stability analysis shows that the ă non-application of a reducing factor to Kalker's coefficients ă overestimates the critical speed.