High-density distributed fiber optic sensing system based on Rayleigh backscattering effect

A High-density distributed fiber optic sensing technique based on Rayleigh backscattering effect is introduced here. This technique can assess the strain along the entire optical fiber length with a resolution in the submilimeter range. It was used to measure the strain of carbon fiber reinforced composite laminates under static bending tests, and the regularity of strain distribution under different conditions were studied. According to the experimental pavement mothed of the optic fiber, with 2 mm spatial resolution, 480 points' strain profiles were generated for each laminate, and positive linear relationship between loads and strain size was observed. Fiber Bragg Gratings (FBGs) were bonded to the laminates co-located with the distributed sensors for comparison. Very good agreement is obtained between strain measures for the laminates with the two kinds of sensors. It shows that the distributed sensing technique enables to monitor the strain very detailed in a global mapping of the entire structure, realizing distributed measurement, and demonstrates its high potential for damage detection of composite materials.