The time domain analysis of interactions in the wheel - rail contacts due to discontinuous time periodic loads

In this paper, we present Fourier series less approaches for determining the energy produced by discontinuous time periodic forces in the wheel-rail contacts of the railway track systems. The vehicle system model used in this study consists of a quarter car supported on a bogie, while the side frame is supported on two wheel sets. The main advantage of the presented method is the total elimination of frequency analysis, which in effect introduces important simplifications in the identification of the energetic effects in the contact. Fundamental properties of contact displacements of the rail surface have been considered on the basis of the newly established method. The contact zone between railway wheels and the rail surfaces made of bulk materials is perceived as strong enough to resist the normal (vertical) forces introduced by heavy loads and the dynamic response induced by track and wheel irregularities. The analysis is carried out for a wheel running on an elastic rail rested on sleepers arranged on completely rigid foundation. The established model of the wheel-rail contact dynamics has been applied to that same roll plane, but with taking into account a nonlinear characteristic of the sleeper with respect to the ground. Attention then is focused completely on the modelling of the energy absorbed by the rail. The applied method employs the energy state variables as time functions leading to determine the susceptibility of a given contact on the strength induced by the rail roll