Applicability of acoustic noise correlation for structural health monitoring in nondiffuse field conditions
Résumé
Ambient noise correlation offers an elegant way of passively caracterize a medium. The principle is that in diffuse field condition, Green’s function between two sensors can be retrieved from the cross-correlated received signals. Here, the technique is applied in conditions where convergence toward Green’s function is not ensured. Since the obtained information is sensible to the medium state, it is still exploitable for damage detection provided a baseline version is available for comparison. This requires the identification of the acoustic source characteristics at the instant of measurement, which could be achieved using the signal measured at a “reference” sensor.