Railway Vehicle Dynamics: Some Aspects of Wheel–Rail Contact Modeling and Optimization of Running Gears

A significant part of a computer-aided model of a railway vehicle is the description of forces at contact between wheel and rail. Computation of these forces is one of the most time-consuming CPU operations during the simulation process. Mathematical models of the contact forces often lead to stiff equations of motion because of high contact stiffness. In this article, an approximate, nonstiff method for computing the nonelliptical contact problem and some results of its implementation are presented. Optimization of multibody systems is presented as a multicriteria optimization problem. The problem of forming objective function is still open due to wide variety of conflicting criteria, which have to be reduced to a scalar function. Implementation of an approach for optimizing dynamic systems based on the analytic hierarchy process for getting the scalar objective function is presented. The application of the developed approach to railway vehicle dynamics is considered.