High-resolution distributed fiber-optic monitoring of composite beams production

Distributed monitoring of strain and temperature is performed repeatedly during the production and curing of a composite material beam, over more than 30 hours. The measurements are based on stimulated Brillouin analysis of light propagating along an optical fiber that is embedded underneath the outer-most structural layer of the beam, during its production. The Brillouin analysis protocol provides high spatial resolution of 4 cm, and sensitivity of ±1 °C or ±20 με. The results indicate an initial heating of the beam, by as much as 20-25 °C over several hours, and residual compressive strain in the sensing fiber on the order of 200 με. The measurement procedure is applicable to quality control and production monitoring of advanced composite materials structures.