Abstract
Experiments have been performed for the coplanar fatigue crack growth under non-proportional mixed mode loading. In the experiments, sequential and overlapping mode I and mode II, or mode I and mode III cycles were applied to the crack in the specimen made of wheel or rail steel. The growth rates were obtained and compared in terms of equivalent stress intensity factor ranges. Fracture surfaces near the crack tip region of tested specimens were observed by SEM. For the investigation of incipient crack path direction, the elasto-plastic finite element analyses were performed with the combination of the maximum tangential stress criterion.
