Calculation of minimum crack size for growth under RCF between wheel and rail

초록

Surface initiated cracks in rail by repeated rolling contact between wheel and rail have been one of growing problems in high speed rail. Estimation of a minimum crack size for growth and its growth rate are the most demanding work to develop cost effective rail maintenance strategy and prevent rail from failure. In this study, we did a series of modelling runs to predict a minimum crack size for growth, which was defined as a crack that grew fast enough to ‘keep ahead’ of its removal by surface truncation, in various contact conditions. For this purpose, we developed crack growth simulation software based on the F&B model suggested by Fletcher and Beynon, and calculated the minimum crack sizes for growth considering the effect of dominant contact contributors such as contact pressure, surface friction coefficient, surface wear rate and initial defect size. The minimum crack sizes for growth were calculated from 0.19 to 3.60mm.