Phase-field modeling of anisotropic fracture of additively manufactured parts

Additively manufactured materials exhibit anisotropic mechanical and fracture behaviors, due to the layered structure inherent from the manufacturing process. This work presents a multiscale framework to investigate the anisotropic fracture of additively manufactured parts using the phase-field fracture method. Herein, the anisotropic properties including anisotropic elasticity and anisotropic fracture resistance are considered, with both effects on crack patterns studied separately and combined. The orientation-dependent elastic constants are calculated by the computational homogenization approach, while the stress-based spectral decomposition method of stress and strain energy is adopted as a result of anisotropic elasticity. A direction-dependent structural tensor which relates to the printing process is introduced to the phase-field fracture model to account for the anisotropic fracture toughness. The model is first examined with a single-edge notched tensile test and then applied to additively manufactured parts where the predicted crack patterns agree well with the experimental results. The simulation results show that it is necessary to include both anisotropic elasticity and anisotropic fracture properties to accurately capture the fracture behaviors of additively manufactured parts.