A direct method for the extension of FastSim under non-Hertzian contact conditions

Abstract

[EN] In wheel-rail contact mechanics, there coexist different models characterised by their ability to reproduce the real phenomenon and the time associated with computing the solution. In simulation of the vehicle dynamics, the increase in the computational performance places researchers close to a horizon in which it is possible to implement the most realistic theories (Variational Theory or finite elements), although at present the use of these models is mainly limited to offline calculations, far from real-time simulation. In this context, this work presents a tangential contact theory that is an intermediate point between simplified models (unable to model non-Hertzian contact) and more realistic models (whose complexity triggers simulation times). The tangential contact model proposed is based on the FastSim algorithm, whose precision comes from the algorithm convergence to the results of an exact adhesion theory (i.e. when creepages tend to zero). The impossibility of considering Kalker's Linear Theory as an adjustment method when the hypotheses of the Hertzian model are not fulfilled leads to the adoption of the Kalker's steady-state CONTACT version in adhesion conditions. The calculations presented through the proposed algorithm provide errors for creep forces lower than 4% with computational times one order lower than the Variational Theory.