Including Pre‐Existing Fractures in Phase Field Fracture Models

ABSTRACT The phase field method for fracture modelling has, in recent years, become the method of choice for complex fracture problems, especially those involving branching, merging, or nucleating fractures. As the number of applications of the phase field method has expanded, the importance of assessing its accuracy has increased. One important factor in enabling the production of accurate results is making appropriate choices to include pre‐existing fractures in the model setup. In this work, seven methods for including pre‐existing fractures are identified—six from existing literature, and one new method derived from the phase field energy functional. These methods are tested in their ability to reproduce an analytical 1D solution for their phase field, and their performance in a mode I fracture problem, with their load‐displacement and energy release rate responses analysed. The authors' proposed method exhibits robust performance and shows promise in matching theoretical predictions and reducing computational cost in some settings.