Mechanics of small damage in fiber-reinforced composite materials

In this work the new concept of small damage is examined within the framework of continuum damage mechanics. In particular, special emphasis is given to a new damage variable that is defined in terms of the elastic stiffness of the material. Only the scalar case is studied in this work. The scalar definition of the new damage variable was used recently by many researchers. The investigation of the new scalar damage variable and the new concept of small damage is carried out on fiber-reinforced composite materials. Furthermore, the two approaches to damage analysis in composite materials are re-examined in this work using the new damage variable. These are the well known overall and local approaches established in the literature of damage mechanics. It is noted that the examination of these two approaches that is presented here applies to both small and large damage mechanics. Finally, the two approaches are compared mathematically and are shown to be equivalent.