Monitoring of process induced strains in a single fibre composite using FBG sensor: A methodological study

A partially embedded long fibre-Bragg grating (FBG) into an epoxy cylindrical specimen is used to monitor the strain distribution evolution along its axis when subjected to subsequent cycles of thermal ageing at 70° and 110 °C. Assuming a total volume reduction of 2.5% at full cure, the epoxy conversion at the end of the thermal cycles was found ∼85%. Using strain data from the FBG, the coefficient of thermal expansion was evaluated as ∼11.5 ×...