Surface crack propagation analysis in rail head

초록

Rail failure generally occur due to fatigue defects that form and grow in the rail steel as a result of cyclic forces caused by the repeated passage of trains over the rails. Estimation of critical crack size and crack growth rate is an essential to prevent rail from failure and develop cost effective railway maintenance strategy. In this study, we predict critical crack size and crack growth rate of a rail with a surface crack. For this purpose, a rail with a semi-elliptical surface crack is modeled. Global bending stress and contact stress at the rail surface are calculated by applying the Timoshenko…s beam model and Hertzian contact model, respectively. Also, thermal stress and residual stress are superposed to calculate the total stress history at the crack tip. Parameter studies on initial crack size, da/dN-？？K curve, service temperature, and crack aspect ratio are conducted by setting a base-line value for each factor, and then varying the value from the baseline one factor at a time.