An enhanced damaged plasticity model for concrete under cyclic and monotonic triaxial compression

The concrete damaged plasticity model (CDPM) in ABAQUS has been widely used to capture the damage behavior and nonlinear deformation characteristics of concrete structures. However, there are no available guidelines for defining the damage variables in this model. Modeling the behavior of concrete under high hydrostatic pressure (HP) is also beyond the scope of the CDPM. As a result, an enhanced model within the CDPM theoretical framework for modeling concrete under monotonic and cyclic triaxial compression (TC) was developed in this paper. Based on the 3-parameter Menétrey-Willam strength criterion (MWSC), the constant aspect ratio Kc, which dominates the shape of the failure surface in the deviatoric plane, of the original yield criterion was modified to be an HP-dependent variable to account for concrete behavior under high confining pressures. Besides, a corresponding confining pressure-dependent compression hardening/softening rule was developed based on the modified failure criterion. Moreover, both the compressive and tensile damage variables were explicitly derived as functions of the inelastic strain since improved relationships between the total strains and the corresponding plastic strains, as well as the effect of the lateral confining pressure on the compressive damage variable, was established. Furthermore, the predictive capability of the enhanced CDPM for concrete was demonstrated through comparisons of numerical simulations and experimental tests. The numerical predictions were in satisfactory agreement with the experimental results reported in the technical literature. Therefore, the enhanced CDPM in ABAQUS can properly capture the strength and ductility behavior of concrete under cyclic and monotonic TC.