Feasibility of Passive Tomography of Extended Defects Using Ambient Elastic Noise Correlation

AbstractUsing guided waves in structural health monitoring seems interesting because of their capability 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 can make a very robust and low power SHM system. An active tomography image has been performed with a time-of-flight tomography algorithm using experimental data produced by piezoelectric transducers. Comparison between active signals and passive signals which come from cross-correlation of ambient noise produced by compressed air sprayed on an aluminum plate shows that it is possible to detect time-of-flight passively