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Towards Passive Guided Wave Tomography of Extended Defects Using Ambient Elastic Noise Cross-correlations

T. DRUET, M. JULES, B. CHAPUIS, G. LAFFONT, E. MOULIN

Abstract


Guided waves show great potential for structural health monitoring for their ability to propagate over long distances. This paper shows that tomography algorithms using guided waves in plate-like structures and cross-correlation of ambient noise can be combined to process the passive tomography of a structure. This could prove to be a low power, robust sensing unit for SHM systems. Moreover, if appropriate sensors are used, for example fiber Bragg gratings, the sensors intrusiveness in the structure can be limited. An active tomography image has been performed with a time-of-flight tomography algorithm using experimental data produced by piezoelectric transducers. Comparison between active and passive signals which come from cross-correlation of ambient noise produced by spraying compressed air on an aluminum plate shows that it is possible to detect time-of-flight passively. The sensors used to perform this comparison were both piezoelectric transducers and fiber Bragg gratings.

doi: 10.12783/SHM2015/249


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