A Continuum Mechanics Characterization of Damage in Composite Materials

The mechanical response of a composite material damaged in fatigue, or in any other loading mode, is characterized by a set of vector fields, each representing a damage mode. Constitutive equations are derived for isothermal small-deformation behaviour following attainment of a damage state. For small damage, the elastic constants of a damage state are related to those of the undamaged state. The usefulness of these relations in characterizing the development of damage, for instance during fatigue, is discussed.