ABSTRACT
Damage in metals is mainly the process of the initiation and growth of micro-cracks and cavities. At that scale the phenomenon is discontinuous. Kachanov (1958) was the first to introduce a continuous variable related to the density of such defects. This variable has constitutive equations for evolution, written in terms of stress or strain, which may be used in structural calculations in order to predict the initiation of macro-cracks. The three main types of damage are:
1. Ductile damage: the constitutive equations for this type of damage have been formulated by Lemaitre (1984, 1986), Lemaitre and Dufailly (1987), and Voyiadjis and Kattan (1992). Both elastic and elasto-plastic damage effects were considered.
