Micromechanical modeling of the coated steel sheets thermomechanical behavior

Micromechanical model is developed to determine the macroscopic thermomecha nical behavior of metallic coated sheets. To study the thermoelastoplastic behavior of such heterogeneous materials (in general, substrate + inter-pha se + coating), classical localization and homogenization techniques are use d in the framework of continuum mechanics with small perturbations hypothes is. Coatings are considered as a multi-laminated medium in which every laye r or phase exhibits an anisotropic thermoelastoplastic behavior with plane and perfect interfaces. The real heterogeneous material is replaced by a fi ctitious homogeneous one called Equivalent Homogeneous Material (E.H.M.). T o consider the effect of anisotropy, the Hill's yield criterion for anisotr opic strain-hardening materials is used. The interface problem is solved by introducing the interfacial operators of solid mechanics. One general "thr ee-phase" model is proposed and considered in the case of damaged coating b y taking into account the coupling between plasticity and damage phenomena. First results show the effects of damaged or undamaged metallic coating on elastoplastic behavior of coated steel sheets.