J. Phys. IV France 105 (2003) 55
A non-classical micro-macro transition towards the anisotropic damage behaviour of particulate compositesC. Nadot-Martin, N. Lesur, D. Halm, H. Trumel and A. Dragon
Laboratoire de Mécanique et de Physique des Matériaux, UMR 6617 du CNRS, École Nationale Supérieure de Mécanique et d'Aérotechnique, 1 avenue Clément Ader, BP. 40109, 86961 Futuroscope-Chasseneuil cedex, France
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  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.
© EDP Sciences 2003