Constitutive response and consistency of Lee-Fenves concrete damage-plasticity model under non-proportional loadings

The present work attempts to address the issue of constitutive response and consistency of plastic strain-induced anisotropy of Lee-Fenves Concrete Damaged Plasticity (CDP) constitutive model. The CDP model, which comes to be available within the ABAQUS commercial FEM platform, shall be able to reproduce typical features of the failure process of quasi-brittle materials subjected to multiaxial cyclic loadings, according to FEM modelizations and simulations at the structural scale that may arise in different challenging engineering contexts. This is achieved by combining an effective stress-based nonassociative hardening/softening plasticity model, with an isotropic damage model based on plastic strains and stiffness loss/recovery capabilities during microcrack opening/closing, at a smeared continuum scale. Herein, several numerical analyses are performed, starting at a constitutive-driver level, to experiment the outcomes of the constitutive description and to quantify the amount of material anisotropy induced by plastic deformation, for representative non-proportional loading histories, which may involve the rotation of principal strains/stresses (Willam’s test). Extrapolating implications and outcomes at the structural scale may then consistently follow, in the realm of significant practical applications within different structural engineering contexts.