Numerical prediction of crack front shape during fatigue propagation considering plasticity-induced crack closure

• 3D simulation of plasticity induced crack closure throughout fatigue propagation.
• Prediction of the crack front curvature throughout fatigue propagation through remeshing.
• Local effective stress intensity factor as a driving force.
• Explanation of the experimentally observed crack shape.

This paper deals with the numerical study of the plasticity-induced crack closure of through-thickness plane cracks, in CT specimens made of 304L austenitic stainless steel. The initial crack front is straight. Constant amplitude of the stress intensity factor is applied in order to limit the loading history influence. Crack propagation is achieved through automatic remeshing, with elastic and plastic parallel calculations. The local effective stress intensity factor range is calculated along the crack front, and considered as the propagation driving force. A comparison with experimental crack front shape allows the validation of the employed method, although some discrepancies remain near the specimen edges.