Citation

Lee HW, Sandu C, Holton C. Veh. Syst. Dyn. 2012; 50(2): 299-321.

Copyright

(Copyright © 2012, Informa - Taylor and Francis Group)

DOI

10.1080/00423114.2011.582121

PMID

unavailable

Abstract

Accurately estimating the coefficient of friction (CoF) is essential in modelling railroad dynamics, reducing maintenance costs, and increasing safety in rail operations. The typical assumption of a constant CoF is widely used in theoretical studies; however, it has been noticed that the CoF is not constant, but rather depends on various dynamic parameters and instantaneous conditions. In this paper, we present a newly developed three-dimensional nonlinear CoF model for the dry rail condition and test the CoF variation using this model with estimated dynamic parameters. The wheel-rail is modelled as a mass-spring-damper system to simulate the basic wheel-rail dynamics. Although relatively simple, this model is considered sufficient for the purpose of this study. Simulations are performed at a train speed of 20 m/s using rail roughness as an excitation source. The model captures the CoF extremes and illustrates its nonlinear behaviour and instantaneous dependence on several structural and dynamic parameters.