A cohesive fracture-enhanced phase-field approach for modeling the damage behavior of steel fiber-reinforced concrete

This study introduces a novel computational framework based on the phase-field fracture/damage model (PFM), providing rapid and accurate predictions of the damage behavior of Steel Fiber Reinforced Concrete (SFRC) material. The framework integrates the interfacial cohesive fracture model with the PFM to depict the interaction between the cementitious matrix and fibers, marking the first demonstration that this model adequately captures both local fracture phenomena between fibers and concrete (such as fiber bridging and interfacial debonding) and mesoscopic stress-strain behavior. Additionally, an enhanced geometric approximation is established based on the spatial distribution density function of fibers and particles, allowing for the transformation of the three-dimensions (3-D) fiber-reinforced material structure into an equivalent two-dimensions (2-D) material. This approach enables the reduction of computational time, a significant limitation of the phase-field method, thereby allowing an in-house code to perform various computations with complex material structures such as SFRC. The effectiveness of the approach is demonstrated through four examples involving variations in the micro- geometry and material properties of SFRC structures, ranging from the simplest configurations to real experimental material structures. Extensive Monte Carlo simulations of the model are also employed to provide results closer to reality, which are then compared with recent experimental data and numerical models, demonstrating the efficacy of the proposed computational model.