Micromechanical-based criteria for the calibration of cohesive zone parameters

This paper presents a new micromechanical model for a collection of cohesive zone models embedded between each mesh of a finite element-type discretization. It aims to forth fully extend the previous linear results of [1] to the calibration of damageable cohesive parameters (cohesive peak stress, critical opening displacement, cohesive energy, etc). The main idea of the approach consists in replacing the underlying cohesive-volumetric discretization by an equivalent ’matrix-inclusions’ composite. The overall behavior of this equivalent composite is estimated using homogenization schemes (Hashin-Shtrikman estimate and the modified secant method) and is given in a closed-form as function of both cohesive and bulk properties and the mesh density. In the particular case of a bilinear cohesive law a micromechanical damage model for quasi-brittle materials is derived. The corresponding local-to-global relationships are obtained for any overall triaxiality loading ratio.