Simulating the Behaviour of a Rail String Segment under Dynamic Impac

Abstract

The paper presents a mathematical model for behaviour of a rail string segment bound by several railway sleepers. The model makes it possible to account for prestressing due to joining rail sections into a string, for anisotropic properties of the rail-and-sleeper assembly, and effects caused by the rolling stock for various initial loading conditions. We considered eleven functions describing wheel--rail contact. These functions enable us to select the most accurate model to describe the effects that vehicles have on railway segments that may differ in design specifics, mechanical properties of materials used, operation modes, and the presence of flaws on the rail tread and wheelset tread. The wave equations used to describe the behaviour of a rail string segment can simulate the process of elastic wave propagation after wheelset contact takes place, which is considerable in the case of high vehicle velocities. The investigation conducted allowed us to plot the wheel--rail interaction force for various contact models. The functions specified make it possible to select the optimum force ratio, taking into account the following: geometrical, mechanical and design parameters of the railway segment; operation modes; and the functions sought for in terms of obtaining the desired maximum contact force, contact duration, and loading and relief times