Practical Tool for the Prediction of Plastic Flow in Railway Curves

This paper investigates the wheel-rail contact forces and stress distributions that lead to lateral plastic flow of material in the railhead. A 250 m radius curve is taken as an example with rail profiles measured over an 8 month period. Vehicle dynamics simulations have been carried out to investigate how the wheel-rail contact forces change over time, as the rail profile evolves. The calculated forces have then been applied to a Finite Element Analysis (FEA) to investigate plastic work and cumulative strain within the rail. The work presented in this paper is part of a larger project which has the aim of developing a simple analytical approach for predicting rates of plastic flow based on calculated wheel-rail contact forces (without the need for computationally intensive FEA analysis). Vehicle speed on curves (and therefore cant excess/deficiency) appears to have a significant effect on rates of Effective Plastic Work (EPW) as does contact size and shape. Work is ongoing to continue investigating parameters that affect rates of lateral plastic flow and to develop a 'plastic work damage index'; building on a previous study [1].