Damage measurements

Eight different methods are described to measure damage defined as the effective surfacic density of micro-cracks and cavities in any plane of a representative volume element: (i) direct measurements such as the observation of micrographic pictures and the measurement of the variation of the density; (ii) non direct measurements which are destructive such as the measurement of the variations of the elasticity modulus, of the ultrasonic waves propagation and of the cyclic plasticity or creep responses, or non destructive such as the measurement of the variation of the micro-hardness and of the electrical potential.