Diffuse Acoustic waves Correlation in Layer-On-Substrate structures – DACLOS

This project paves the way for an original microstructure auscultation technique based on diffuse wave correlation (DWC). The objective is the non-destructive testing and evaluation (NDT&E) of Layer-On-Substrate (LOS) specimens. Currently, one possibility to inspect these structures consists in using IDTs for emission and LDV detection. The implementation of the diffuse acoustic waves correlation and the associated principle of passive Green's function reconstruction should allow to detect and image heterogeneities in 2D. Promising applications on plates subjected to low frequency ambient noise (10-30 kHz) have been shown. Given the size of the LOS structures, it is now necessary to show that such analysis can be conducted at higher frequencies (10-30 MHz). This "jump" in frequency from (10-30 kHz) to (10-30 MHz) for DWC technique presents double challenges: create an artificial diffuse noise, adapted instrumentation and signal-processing.