Experimental study of passive defect localization in plates using ambient noise

Lynda Chehami (1, 2) , Julien de Rosny (3) , Claire Prada (4, 5) , Emmanuel Moulin (1, 2) , Jamal Assaad (1, 2)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 TPIA - IEMN - Transduction, Propagation et Imagerie Acoustique - IEMN
3 ESPCI Paris - Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris
4 IL - Institut Langevin - Ondes et Images (UMR7587)
5 CNRS - Centre National de la Recherche Scientifique

Passive listening methodology has been shown to be a practical and effective method for passive structural health monitoring. In this work, this approach is applied experimentally to monitor the occurrence of defects in thin aluminum plates. A correlation matrix is estimated from noise vibrations recorded on a transducer array. A defect is localized by applying a beamforming algorithm to the difference between the correlation matrices obtained with and without the defect. We successfully detect defects for different kinds of noise sources. Moreover, we show that this technique is robust to detect massive inclusions, holes, and cracks. With a vibrometer, we observe that the fidelity of the estimated transient responses strongly depends on the number of uncorrelated noise sources. Finally, we show that the defect is successfully localized even if the noise source distribution is not uniform, provided that it remains spatially stationary between the states with and without defect. A simple theoretical framework is proposed to interpret these results.

Domaines: Sciences de l'ingénieur [physics]; Physique [physics]

Lynda Chehami, Julien de Rosny, Claire Prada, Emmanuel Moulin, Jamal Assaad. Experimental study of passive defect localization in plates using ambient noise. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2015, 62 (8), pp.1544-1553. ⟨10.1109/TUFFC.2014.006935⟩. ⟨hal-04087445⟩