Experimental Broadband Signal Reconstruction for Plate-like Structures

In the Structural Health Monitoring (SHM) field, the Acoustic Emission (AE) technique is a passive method by which damage is localized and identified by capturing Lamb Waves (LW) signals propagating in a plate-like structure. The reconstruction of emitted signals from damage at the source location constitutes one of the main challenges faced by the SHM community. Recently, the application of a Frequencies Compensation Transfer Function (FCTF) has been used to reconstruct narrowband (NwB) and broadband (BdB) signals through a hybrid experimental and numerical Time Reversal (TR) process on aluminum plates. This study aims to reconstruct through experimental methods different types of NwB and BdB signals on different plate-like structures making use of FCTFs. In particular, Hanning Window (HW) and Numerical Band Limited Broadband (NBLB) signals have been reconstructed for aluminum and steel plates. The results obtained in this study show how the FCTF method can be applied to different types of materials in plate-like structures. Moreover, the FCTF method has been applied on real BdB signals emitted by the Pencil Lead Break (PLB) technique and Rock Impact (RI) test. These last results prove that the FCTF method is able to compensate for the frequency changes on a single wave packet. Such results are fundamental, as they open the possibility to reconstruct any type of source signals emitted by any damage type.