Optical Fiber Sensors for Ultrasonic Structural Health Monitoring: A Review

Abstract

Guided waves (GW) and acoustic emission (AE) -based structural health monitoring (SHM) have widespread applications in structures, as the monitoring of an entire structure is possible with a limited number of sensors. Optical fiber-based sensors offer several advantages, such as their low weight, small size, ability to be embedded, and immunity to electro-magnetic interference. Therefore, they have long been regarded as an ideal sensing solution for SHM. In this review, the different optical fiber technologies used for ultrasonic sensing are discussed in detail. Special attention has been given to the new developments in the use of FBG sensors for ultrasonic measurements, as they are the most promising and widely used of the sensors. The paper highlights the physics of the wave coupling to the optical fiber and explains the different phenomena such as directional sensitivity and directional coupling of the wave. Applications of the different sensors in real SHM applications have also been discussed. Finally, the review identifies the encouraging trends and future areas where the field is expected to develop.

Accuracy of Distributed Strain Sensing with Single-Mode Fibre in Composite Laminates under Thermal and Vibration Loads

“…Tis is mainly because of the strain transfer rate between the substrate and SMF. In the work of [46], a model is built to estimate this strain transfer rate α by equation (8). Te expression of k in this equation is shown in equation ( 9) as follows:…”

“…Various fbre optical (FO) sensors have been adopted in diferent SHM applications [7][8][9]. For example, buckling detection based on distributed FO sensors [10], a hybrid piezoelectric-fbre optic system based on fbre Bragg gratings (FBG) [11,12], embedded FBG sensors in SHM of complex composite structures [13], and sandwich panel [14].…”

Phase Stability Control of Optical Fiber Partial Discharge Ultrasonic Sensing System

“…The traditional acoustic measurement uses piezoelectric transducers (PZT) to sense the ultrasonic wave generated by partial discharges in power equipment. However, PZT has a relatively weak sensitivity and is difficult to multiplex, and as such, it struggles to meet the needs of partial discharge detection in power equipment [ 5 ]. A variety of optical fiber ultrasonic sensors have been developed rapidly and provides a new technical scheme for partial discharge ultrasonic detection.…”

Development of a Fault Detection Instrument for Fiber Bragg Grating Sensing System on Airplane

“…However, the FBG sensor's faults or failures become more frequent than the structural damage during the sensor lifetime owing to their own natural aging, line failure, installation failure, harsh operational environment (e.g., temperature, humidity and moisture), and so on. Furthermore, the sensor detection using the one-by-one method will take a long time and increase the maintenance costs, especially in the large sensor network [17,18]. The early identification of faults or failures in FBG sensors is the most important aspect of fault detection to ensure data accuracy and reliability [19,20].…”