Modelling fatigue crack growth in shape memory alloys

Abstract

Abstract We present a phase field‐based framework for modelling fatigue damage in Shape Memory Alloys (SMAs). The model combines, for the first time: (i) a generalized phase field description of fracture, incorporating multiple phase field formulations, (ii) a constitutive model for SMAs, based on a Drucker–Prager form of the transformation surface, and (iii) a fatigue degradation function, with damage driven by both elastic and transformation strains. The theoretical framework is numerically implemented, and the resulting linearized system is solved using a robust monolithic scheme, based on quasi‐Newton methods. Several paradigmatic boundary value problems are addressed to gain insight into the role of transformation stresses, stress‐strain hysteresis, and temperature. Namely, we compute Δ ε − N curves, quantify Paris law parameters, and predict fatigue crack growth rates in several geometries. In addition, the potential of the model for solving large‐scale problems is demonstrated by simulating the fatigue failure of a 3D lattice structure.