ESTIMATION OF RAIL WHEEL WEAR AND OPTIMIZATION OF WHEEL PROFILE

Abstract

A methodology and a simulation tool to predict changes of wheel profiles due to wear have been developed. The methodology is based on a load collective concept, where a load collective determines a set of dynamic time-domain simulations that is chosen to expose the wheels to contacts with the rails that they are likely to encounter in the application at hand. In the load collective, the railway network is primarily discretisized based on the curve radius distribution. Key parameters are found by performing parametric studies, where the input load collective is varied. Track design geometry parameters and rail profiles are most important to vary in the load collective.The vehicle-track simulations are performed with the MBS (Multi-Body-System) tool GENSYS and the wheel-rail contact mechanics modelling is done with the Hertzian theory in combination with the simplified theory by Kalker (FASTSIM). Material removal, or the profile updating, must be performed iteratively since the wheel profiles affect the wheel-rail contacts and the vehicle-track response. A wear step is defined as one loop in the main programme and corresponds to a maximum wear depth on the wheel profiles and the pertinent simulated running distance of the vehicle. The maximum wear depth in each wear step has been set 2000 km of running distance.Archard's wear model is used . Wear due to braking has been estimated by introducing a factor that increase wear due to straight track running.