Abstract EN:

This work is devoted to the modelling of the behaviour of a class of highly-filled particulate composites in presence of damage by grain/matrix debonding. To this aim, a scale transition technique, called "morphological approach" (MA) has been chosen. It was formulated by Nadot et al. (2006) for a given damage state as an extension of the work initially proposed by Christoffersen (1983). Several tools dedicated to the description of damage evolution (defects nucleation, closure and re-opening criteria) are here formulated. The MA thus completed is then qualitatively evaluated for linear elastic isotropic constituents. The evaluation is performed via a discrete numerical solving procedure allowing to draw a chronological list of damaging events such as nucleations, closures and openings of defects in the material. More precisely, a prediction/correction algorithm enables to adapt automatically calculation steps to the sequencing of nucleations. Therefore, the influence of new nucleations is properly taken into account in the estimate of local and global responses. Several significant loading paths are chosen to prove that the MA allows to describe damage characteristics (access to position, orientation and morphology of microdefects, leading to the construction of 3-D representations of the damaged microstructure) as well as its influence on both scales (unilateral effects, couplings between primary and damage induced nisotropies, identification and estimations of local strains of the contributions which constitute them. . . ). Eventually, the basis for further extensions of the model such as the description of the viscoelastic behaviour of the matrix, or the transposition to a more realistic frame of finite transformations, are set. In particular it shown that the kinematic formulation of the criteria proposed is a great asset for the extensions considered.