A single three-parameter tilted fibre Bragg grating sensor to monitor the thermosetting composite curing process

Abstract The unique sensing features of the tilted Fibre Bragg Grating (TFBG) as a single three-parameter optical sensor are demonstrated in this work, to monitor the manufacturing process of composite materials produced using Vacuum Assisted Resin Transfer Moulding (VARTM) process. Each TFBG sensor can measure simultaneously and separately strain, temperature and refractive index (RI) of the material where the optical fibre is embedded. A TFBG embedded in a 2 mm glass-fibre/epoxy composite plate was used to measure the thermomechanical variations induced during the curing process. At the same time, the RI measurements, performed with the same TFBG sensor, can estimate the degree of cure of the resin. The TFBG sensor shows to be a valid and promising technology to improve the state of art of sensing and monitoring in composite material manufacturing. Graphical Abstract