A non-classical micro-macro transition towards the anisotropic damage behaviour of particulate composites

Abstract
The complex problem of micromechanically based constitutive description of composite materials for which damage consists in grain-matrix debonding is treated employing the homogenization method initially proposed by Christoffersen [1] for elastic bonded granulates. The localization relations (microscopic level) as well as the homogenized stress are established and discussed for a fixed state of damage (i.e. for fixed numbers of open and closed cracks) and using the hypothesis of no sliding on closed crack lips. Finally, a complementary, thermodynamically motivated approach is performed in order to express the crack opening effect as a function of macroscopic strain and of two damage variables involving granular aspects and emerging from the scale transition.