An Optical Interferometric Triaxial Displacement Sensor for Structural Health Monitoring: Characterization of Sliding and Debonding for a Delamination Process

Abstract

This paper presents an extrinsic Fabry–Perot interferometer-based optical fiber sensor (EFPI) for measuring three-dimensional (3D) displacements, including interfacial sliding and debonding during delamination. The idea employs three spatially arranged EFPIs as the sensing elements. In our sensor, the three EFPIs are formed by three endfaces of three optical fibers and their corresponding inclined mirrors. Two coincident roof-like metallic structures are used to support the three fibers and the three mirrors, respectively. Our sensor was calibrated and then used to monitor interfacial sliding and debonding between a long square brick of mortar and its support structure (i.e., a steel base plate) during the drying/curing process. This robust and easy-to-manufacture triaxial EFPI-based 3D displacement sensor has great potential in structural health monitoring, the construction industry, oil well monitoring, and geotechnology.

Experimental Investigation of the Natural Bonding Strength between Stay-In-Place Form and Concrete in FRP-Concrete Decks/Beams

“…The advantageous properties of light-weight, high tensile strength along the fiber direction, and durability under harsh environments have made fiber reinforced polymer (FRP) composites an advanced and competitive solution to repair and retrofit civil engineering structures [1][2][3]. There has been an increasing number of field applications using FRP bars and sheets to replace steel bars [1][2][3][4][5][6][7][8][9][10] and to strengthen existing structures [11,12]. FRP thin-walled profiles have also been put into field applications of newly built pedestrians, or to replace the old decks of small and medium span bridge superstructures [13][14][15].…”

Identification of Volatile Organic Liquids by Combining an Array of Fiber-Optic Sensors and Machine Learning

“…FOSs have exploded in popularity in engineering societies because they outperform traditional electronic sensors by offering unique benefits such as small size, immunity to electromagnetic interference, high sensitivity and resolution, robustness in harsh environments, remote operation, and multiplexing/distributed sensing capabilities . FOSs have been used for measuring various parameters such as displacement, strain, temperature, and pressure. − Currently, FOSs are fabricated following different designs, such as the fiber-optic gyroscopes, the fiber grating sensors, the interferometer sensors, and so forth. Fiber-optic interferometers are widely utilized in the analysis of liquid droplets, − especially, the extrinsic Fabry–Perot interferometer (EFPI)-based sensor, which has demonstrated tremendous potential because it is simple and highly sensitive. , Using the EFPI approach to monitor liquid droplet evaporation events has been previously reported in the literature. − However, the previous studies focused on evaporation dynamics, but they did not use the experiment data to identify liquids.…”

“… 11 FOSs have been used for measuring various parameters such as displacement, strain, temperature, and pressure. 12 − 15 Currently, FOSs are fabricated following different designs, such as the fiber-optic gyroscopes, 16 the fiber grating sensors, 17 the interferometer sensors, 18 and so forth. Fiber-optic interferometers are widely utilized in the analysis of liquid droplets, 19 − 21 especially, the extrinsic Fabry–Perot interferometer (EFPI)-based sensor, which has demonstrated tremendous potential because it is simple and highly sensitive.…”

An Embeddable Strain Sensor with 30 Nano-Strain Resolution Based on Optical Interferometry

“…Optical fiber extrinsic Fabry-Perot interferometer (EFPI) sensors are also one of the most widely-used optical fiber sensors [14][15][16][17][18]. The majority of reported EFPI strain sensors have a relatively low measurement resolution due to the physical structures of the sensors, such as the well-known fiber-in-capillary structure [19].…”