Influence of Vehicle Dynamics on Wear of Railway Wheel Profiles

摘要

The objective this work is to understand the effect of the vehicle dynamic on the wear generation on wheel and rail profiles, using a mathematical model to study the evolution of railway wheels profile due to wear. The dynamics of a two axle vehicle running on a realistic track was simulated using a Multibody code (Simpack), the contact points are located for each time step using a geometrical module developed in MATLAB, and considering equivalent Hertzian contact patches. The tangential forces are calculated using the Kalker's simplified theory (FASTSIM). The wear coefficients are calculated from the work of Bolton and Clayton. The contact area is divided according to the strip theory into finite elements. Hence, considering dry friction, the wear rate is calculated for each element in the presence of the slip by the proportionality law of wear and frictional work done and, accordingly the accumulative wear for the entire contact area can be obtained. A short real track is adopted as a reference and the wear amount on the wheel profiles is obtained by cumulating the wear. Since the wear of the wheel is due to the wheel-rail interaction, evaluated on the reference track using a MBS code, it is important to know how the wear of the wheel affects the vehicle dynamic and how dynamic affects the wear respectively. To investigate this problem, we use in this work a simple vehicle model (bi-axle vehicle) on a reference track. An overall track length of 13.000 Km is considered comparing different simulations. At first we consider as wear of profiles would not affect dynamics: in this case the wheel dynamic is evaluated once at the beginning using the MBS code. Results obtained in this case are then compared with those obtained repeating the dynamic calculation every 1.300 Km and 260 Km.