Fatigue crack growth behavior of rail steel under mode I and mixed mode loadings

It is necessary to evaluate the fatigue behavior of rail steel under mixed mode loadings to assure the safety of railway vehicles. For this purpose, the stress analysis to investigate static failure and fatigue behavior under mixed mode loadings is performed. The stress analysis results show that the KI/KII tends to increase as the transverse crack below the surface propagates. For the mixed mode, the fatigue crack growth behavior was evaluated using various comparative stress intensity factor ranges ΔKV. Fatigue crack growth rate under the condition of mixed mode is slower than that under mode I, and this difference decreases with the increase of the stress ratio R.