Résumé
Non Interaction Approximation (NIA) is currently used to relate effective elastic moduli to crack density. It also allows one to identify the anisotropy of the crack network.
We investigated thermally cracked glass sample and quantified the crack network (using SEM). From elastic wave velocity measurements, using EMT, we obtained the crack densities: alpha(1) = 0.038 (horizontal one) and alpha(3) = 0.0037 (vertical one).
From SEM observations and image processing we could identify all cracks, count them and determine independently the crack density. These results agree with the previously determined ones from the elastic wave velocity measurements (within a small uncertainty range).
These results indicate that the NIA is quite accurate in the considered range of crack densities, and elastic wave velocity measurements can provide reliable information on their crack distribution and crack density.