Temperature and external strain sensing with metal-embedded optical fiber sensors for structural health monitoring

Abstract

An optical fiber with both temperature and strain fiber Bragg grating sensors were embedded into an aluminum cast structure during the casting process. Temperature and strain calibrations were carried out respectively for the metal-embedded sensors. Temperature and external strain decoupling was further demonstrated in a temperature range from 25 to 80 °C and an external strain range from 0 to ∼110 µɛ. With the interpolated temperature measured by two temperature sensors at different positions, the external strain could be decoupled from temperature and thermal strain at the strain sensor. The temperature and external strain values obtained from our embedded optical fiber sensors agreed well with reference values, revealing the good performance of the metal-embedded optical fiber sensors. The difference between the measured values and the reference values are within ±5 µɛ for external strain and ±1 °C for temperature. With only a single fiber, the in-situ temperature and external strain information in the aluminum structure can be monitored in real time, representing an important step towards fiber-optic smart casts. Our investigation demonstrates that embedded optical fiber sensors can be a promising method for structural health monitoring of metallic structures.

High-Resolution and Large-Dynamic Range Fiber-Optic Sensors Based on Dual-Mode Direct Spectrum Interrogation Method

“…The two strategies (i.e., (2) and (3)) together with the Q factor of the resonant (interference) dip can be significantly improved, yielding an ultrahigh resolution and a large dynamic range sensor; (4) Temperature and strain crosstalk existed in the proposed sensor structure. However, the crosstalk can be resolved using a lot of strategies, including compensation and coefficient matrix strategies [ 22 , 23 , 24 , 25 ].…”

Probing quantum phenomena using fiber Bragg grating sensor

“…where, λB is the Bragg wavelength, Λ denotes the grating pitch and neff represents the effective refractive index of the fiber core. FBG sensing principle is based on change in the Bragg wavelength due to change in grating parameters such as effective refractive index of the core and grating periodicity after being exposed to sensing parameters such as temperature or strain 12 . In our previous work, we have explored light-matter interaction using FBG such as study of photomechanical actuation and photothermal effect in carbon nanotubes, chalcogenides, and graphene which is purely based on photon-absorption property of these nanoscale materials coated on FBG [13][14][15][16][17] .…”

Spectral Behavior of Fiber Bragg Gratings during Embedding in 3D-Printed Metal Tensile Coupons and Cyclic Loading

“…Fiber Bragg grating (FBG) has been the predominant optical sensor selected for embedding in various AM materials including polymer [ 6 ], thermoplastic composites [ 7 ], metal [ 8 ], and metal alloys [ 9 ]. Among the metal additive processes, ultrasonic AM [ 10 , 11 ], solid-state AM [ 12 ], and selective laser melting [ 13 ] have been mostly studied for sensor integration in structures.…”