Passive guided waves measurements using fiber Bragg gratings sensors

Abstract

Guided elastic waves are often studied as an effective solution for Structural Health Monitoring (SHM) systems of plate-like structures thanks to the capacity to propagate on large distances. In typical applications such as monitoring delaminations in aircraft fuselage, a network made of piezoelectric transducer (PZT) is used to emit and receive such waves in the structure. Fiber Bragg grating (FBG) sensors on optical fibers are a promising alternative to PZT for guided waves measurements in practical applications due to the capacity for dense multiplexing and robustness with respect to the environment. However, unlike conventional PZT transducers, FBG sensors cannot emit waves. It is demonstrated here that FBG sensors can be used in combination with a passive diffuse noise cross-correlation technique in order to extract the coherent guided waves propagating between two sensors. This could lead to a system using only FBG sensors in the near future. The reconstructed signals can then be analyzed with usual guided waves algorithms, like in active SHM systems, keeping all the advantages of this kind of monitoring in terms of fine diagnosis. The experimental demonstration shown in this paper is performed at ultrasonic frequencies (20–100 kHz) typically used in guided waves based SHM systems showing the potential of the approach.

Guided wave imaging of composite plates using passive acquisitions by fiber Bragg gratings

“…Furthermore, sensors such as Fiber Bragg Gratings (FBG) on optical fibers, which are unable to emit waves, can be used (Betz et al, 2003). Those sensors have previously been successfully used in combination with piezoelectric transducers (PZT) for active a) arnaud.recoquillay@cea.fr data acquisition (Betz et al, 2003;Takeda et al, 2005), 30 and more recently for passive data acquisition using noise cross correlation to recover the active signal first in seismology (Zeng et al, 2017) and then at ultrasonic frequencies for metallic plates (Druet et al, 2018).…”

“…The combination of ambient noise cross-correlation and Fiber Bragg Gratings sensors, described in (Druet et al, 2018), allows for the determination of the pitchcatch response, that is the response of the structure for a…”

Passive guided wave tomography for structural health monitoring

“…Indeed, in the past years researchers have shown that it is possible to use ambient structure-borne elastic noise instead of actively emit the waves in the structure in order to retrieve the impulse response of the medium between two sensors (Sabra et al, 2007a). Moreover, it has been shown in (Druet et al, 2018) that passive guided wave measurements are possible thanks to the coupling between FBGs and passive methods. In this paper is shown how to perform passive tomography by coupling guided wave tomography adapted to SHM framework (Druet et al, 2019) with passive methods.…”

Effect of Fiber Bragg Gratings Receivers’ Directivity on Guided Wave Tomography of Pipe

“…This method is transposed for pipe structures in [5]. It has also be shown in [6] that passive guided waves measurements using FBG sensors is possible thanks to passive methods such as the ambient noise cross-correlation. In this paper the studies are focused on the impacts that have the fiber Bragg Gratings measurements on guided wave tomography imaging on pipe structure because of the FBG directivity.…”