Prediction of the crack propagation direction in combined static-cyclic multi-axially loaded cruciform specimens

The prediction of crack propagation due to arbitrary mission profiles is still open to debate. One of the main difficulties is how to predict the mission crack deflection angle reliably. In the present paper, experimental and numerical crack propagation data from cruciform specimens subject to a static load along one arm and a cyclic load along the other are reported. It is shown that, for missions purely in the tensile range, the dominant step criterion leads to a better prediction of the deflection angle than the dominant cycle criterion. For all other types of missions, the dominant cycle criterion should be used.