A new formulation of continuum damage mechanics (CDM) for composite materials

Abstract

The damaged elastic properties of composite materials are modeled here in the framework of Continuum Damage Mechanics. The original feature of this model is that it combines different types of variables in describing the damage state of the material. It is now admitted that defects, depending on their reinforcement/matrix properties, can be oriented either by the microstructure, and can then be expressed by a family of scalar variables, or by the loading, in which case tensorial variables must be used. This new model can be used to describe all the essential phenomena observed in composites, namely: initial anisotropy; induced anisotropy, i.e. the effects of the damage on the elastic properties; defaults evolution laws; and closure effects in relation with residual strains. After presenting the general framework of the model, we propose a particular application to the case of ceramic matrix composites.