Integrated Fiber Optic Sensors for Strain, Temperature and Corrosion-Induced Mass Loss Measurement

In this study, a fiber optic sensing system based on long period fiber gratings (LPFG) in LP06 and LP07 modes is designed, fabricated and tested for simultaneous measurements of strain, temperature and corrosion-induced mass loss. It consists of three steel tubes and several Fe-C coated LPFG sensors for long- and short-term corrosion monitoring, respectively, when deployed in proximity and parallel to a steel member. Graphene/silver nanowire (Gr/AgNW) composite was coated on the LPFG surface for efficient Fe-C electroplating due to its high optical transparency and conductivity. The sensor was subjected to both tensile strain and temperature, and submerged in 3.5 wt.% NaCl for 72 hours during corrosion tests. The results showed high accuracy and sensitivity of the integrated sensor