Estimation of wheel/rail adhesion coefficient under wet condition with measured boundary friction coefficient and real contact area

Abstract: This paper describes how to improve the prediction method of the adhesion coefficient by means of the experimentally estimated boundary friction coefficient obtained by two kinds of twin-disc rolling contact machines and the ratio of real contact area to nominal contact area (RCA/NCA) obtained by ultrasonic measurement. The previous prediction method that the authors had already proposed in the last paper was based on Greenwood–Tripp''s rough surface contact model; however, in this study, the authors adopted Lee & Ren''s rough surfaces contact model and focused on the RCA/NCA measured by ultrasonic wave in order to predict the adhesion coefficient under wet conditions with the actual surface contact conditions. As a result, regarding the tendency of adhesion coefficient decreasing with an increase of running speed, a good agreement has been obtained between the results obtained by the prediction method proposed in this study and the measured results obtained by the field-test of Japanese Shinkansen vehicle (series 200). [Copyright &y& Elsevier]