Variational methods in continuum damage and fracture mechanics

Damage is defined as the loss of material stiffness under loading conditions. This process is intrinsically irreversible and, therefore, dissipative. When the stiffness vanishes, fracture is achieved. In order to derive governing equations, variationalmethods have been employed. Standard variational methods for non-dissipative sys-tems are here formulated in order to contemplate dissipative systems as the onesconsidered in continuum damage mechanics.