Mixed mode fatigue crack propagation in a railway wheel steel

The time-dependent stress state of railway wheels leads to fatigue crack propagation in mixed mode (I-II) conditions. In order to model a crack growth scenario in a railway wheel, mixed-mode I-II fatigue crack growth tests were performed on 9 mm thick Compact Tension Shear (CTS) specimens, taken from a Spanish AVE train wheel, using a servo-hydraulic MTS fatigue testing machine with 100 kN maximum load capacity. Fatigue crack growth rates and propagation direction (angle) of a crack subjected to mixed mode loading were measured. A finite element analysis was performed in order to obtain the KI and KII values for the tested loading angles. The crack propagation direction (angle) for the tested mixed mode loading conditions was experimentally measured and numerically calculated, and the obtained results were then compared in order to validate the used numerical techniques. The adopted methodologies, specimens’ dimensions and extraction position, and the obtained results are presented and discussed in the present paper.