Long period fiber grating transverse load effect-based sensor for the omnidirectional monitoring of rebar corrosion in concrete

Abstract

From the angle of sensitivity of the long period fiber grating (LPFG) resonant transmission spectrum, we demonstrate the sensitivity of LPFG resonance peak amplitude changing with transverse loads. The design of a resonant peak modulation-based LPFG rebar corrosion sensor is described by combining the spectral characteristics of LPFG with the expansion state monitoring of rebar corrosion. LPFG spectrum curves corresponding with different rebar corrosion status of the environment under test are captured by the monitoring technique of LPFG transmission spectra, and the relationship between the resonance peak amplitude change and the state of rebar corrosion is obtained, that is, the variation of LPFG resonance peak amplitude increases with the intensifying of the degree of rebar corrosion. The experimental results numerically show that the sensor response has good regularity for a wide range of travel.

Transverse Load Discrimination in Long-Period Fiber Grating via Artificial Neural Network

“…For a birefringent LPG, we may assume the refractive index of birefringence of the optical axes and to be and , respectively, with < . Then, the corresponding orthogonal polarization propagation constants are given by [16]:…”

“…Furthermore, the effect of transverse load in LPGs produces a new linear birefringence in the optical fiber, due to photoelastic effect [16], which modifies the original fast and slow axes propagation constant. Therefore, changes in the phase difference in Eq.…”

Optical Sensors for Corrosion Monitoring

“…[23][24][25][26][27] In Ref. A few works have studied FBGs strain sensors to monitor the corrosion rate in civil engineering structures at single or multiple points.…”

Corrosion Monitoring by Plastic Optic Fiber Sensor Using Bi-Directional Light Transmission

“…Previous studies have delved into the corrosion process and monitoring technologies across various fields, aiming to provide a comprehensive overview [4,5]. These studies sought to assess corrosion initiation and progression by monitoring key factors influenced by corrosion onset, including physical appearance [6], alterations in electrochemical signals [7][8][9][10][11], specimen weight variations [12], structural deformation [13][14][15], alterations in wave propagation characteristics [16][17][18][19], and modifications in the biological corrosion environment [20]. Despite the accuracy of these corrosion monitoring methods, challenges persist, including pinpointing precise corrosion locations, detecting early-stage corrosion, determining corrosion depths, the dependence of data on monitoring environments, and cost-related challenges associated with required monitoring equipment.…”