Damaged Anelastic Behavior of FCC Polycrystalline Metals with Micromechanical Approach

A theoretical micromechanical model is proposed to describe the damaged behavior of polycrystalline metals. Based on the slip theory, a local micro-damage variable representing the transgranular damage is introduced and fully coupled with micro-macro anelastic constitutive equations for FCC polycrystals proposed by Cailletaud (1987, 1992). The micro-damage is supposed to be initiated and then evolved on the activated crystallo graphic slip systems to define isotropic damage at the macroscopic level (i.e., in the Repre sentative Volume Element RVE). The coupling between damage and the behavior at both microscopic and macroscopic levels is carefully discussed. The obtained model is applied and discussed in the case of uniaxial monotonic and cyclic loading, neglecting the quasi- unilateral effect as well as the localization of the fatigue micro-cracks on the surface of the loaded medium.