Abaqus implementation of a phase field–cohesive zone fracture model for composite structures with an implicit scheme

Abstract Commercial and academic finite element software packages typically support either phase field modeling for bulk failure or cohesive zone modeling for interfacial damage. Still, an integrated and flexible framework that combines these two is not easily available in commercial software. This paper presents a phase field–cohesive zone (PF–CZ) model implemented in Abaqus, enabling simultaneous simulation of bulk and interfacial fracture within a single computational platform. This framework combines user-defined elements (UEL) for the phase field formulation that covers both brittle and ductile fractures in the bulk, and various Abaqus built-in cohesive elements with customizable traction–separation laws for the interface. A robust and implicit Newton–Raphson solution scheme combined with a staggered method is employed to solve phase and displacement unknowns, with detailed derivation of the stiffness and tangent stiffness matrices. Validation is performed via three-element tensile tests comparing results from Abaqus and MATLAB-based step-by-step calculations. The model is further demonstrated through simulations of bi-material interface fracture, ceramic matrix composite failure, and four-point bending of reinforced concrete beams. This work offers a verified and extensible framework for researchers and engineers who are new to either the phase field model or the cohesive zone model to study complex fracture scenarios in composite structures. In addition, the limitations of the phase field length scale parameter are analyzed and verified through simulation results. The source code is available at https://github.com/MCMB-Lab/AbaqusPF-CZmodel .