A 3D damage plastic model incorporating low-cycle fatigue effects towards predicting concrete structure failure under cyclic loading

This paper presents a novel 3D constitutive model for concrete that integrates damage and plasticity mechanisms, while explicitly incorporating low-cycle fatigue (LCF) effects to accurately simulate stiffness degradation of concrete under repeated and reversed loading. The plasticity component of the model is an adaption of the classical formulation by Grassl and Jirasek (2006), while the damage part is enhanced through the inclusion of fatigue damage factors. Those improvements enable the model to capture the fatigue-induced stiffness reduction and the key hysteretic behaviors observed in concrete's load-deformation responses. Employing a strain-based approach, the proposed constitutive model is implemented in ABAQUS via its user-defined subroutine, making it suitable for structural-scale predictions. Validation against a range of experimental tests from the literature confirms that the model reliably predicts the failure process of concrete materials/structures under diverse repeated and cyclic LCF loading conditions.