]Laboratoire de Micromécanique et d’Intégrite ́ des Structures, MIST Laboratory,

Since the pioneering works of [1, 2], cohesive zone models are extensively used in failure and damage mechanics. Nevertheless, their numerical implementation as well as the develop-ment of micro-mechanical damage model using cohesive approaches are still important issues of concern. This work aims at determining a micromechanical model for elastoplastic materi-als using intrinsic cohesive approaches in numerical simulations, e.g. the Cohesive-Volumetric Finite Element Method. The idea, first proposed by [3] and recently used by [4], consists in re-placing the cohesive-volumetric discretization by an equivalent ’matrix-inclusions ’ composite: the continuous matrix has the same behavior as bulk elements whereas inclusions correspond to the edges of the underlying mesh (see Figure 1). Figure 1: From cohesive-volumetric discretization to the equivalent ’matrix-inclusions ” com-posite. The overall behavior of such composite is asymptotically obtained using variational homog-enization estimate [5, 6, 7]. The case of isotropic elastic media with bilinear cohesive law is firstly proposed. An elliptic micromechanical damage model is thus derived for brittle materi-als. Then the extension of the model to plastic media is considered. The main interests of this work are: 1. The overall elastic loss due to intrinsic models is a priori estimated and a criteria on cohesive stiffness is proposed. ha l-