Phenomenological Aspects of Damage

The damage of materials is the progressive physical process by which they break. The mechanics of damage is the study, through mechanical variables, of the mechanisms involved in this deterioration when the materials are subjected to loading. At the microscale level this is the accumulation of microstresses in the neighborhood of defects or interfaces and the breaking of bonds, which both damage the material. At the mesoscale level of the representative volume element this is the growth and the coalescence of microcracks or microvoids which together initiate one crack. At the macroscale level this is the growth of that crack. The two first stages may be studied by means of damage variables of the mechanics of continuous media defined at the mesoscale level. The third stage is usually studied using fracture mechanics with variables defined at the macroscale level.