Determination of Creep Force, Moment, and Work Distribution in Rolling Contact With Slip

Abstract

Investigators interested in the wear of wheels and rails frequently use a wear model that postulates wear is proportional to the work done in the contact patch. Most investigators compute the work using the rigid body motions of the wheel and the total creepage at the contact patch. Such an approach gives an overall or integrated measure of the wear in the contact patch. In previous wheel/rail wear work, we have assumed the wear to be distributed parabolically across the contact patch. In order to check this assumption and to permit refinement of our wear modeling technique, we desired to know the distribution of work within the contact patch. In order to compute the work distribution within the contact patch, we must be able to compute the distributions of both the creep force and the creepage. This paper describes a method of computing lateral and longitudinal creep force and creep moment distributions within the contact patch for combined rolling and slip conditions. It also describes the computations of creep distributions within the contact patch. The work distribution is computed from the dot product of force and creepage. The method uses Kalker’s simplified theory to determine the force and creepage distributions. The actual computations are made using a modification of Kalker’s program FASTSIM. A by-product of the work is the determination of the adhesion and slip regions for arbitrary creepage conditions.