Hygroscopic strain measurement by fibre Bragg gratings sensors in organic matrix composites - Application to monitoring of a composite structure

This study is devoted to the identification of the moisture expansion coefficients of composite materials by means of a novel measurement technique. This method is based on the insertion of Fibre Bragg Grating (FBG) sensors between composite layers. The sensor enables to measure the hygroscopic strain induced by moisture diffusion in the plane of the laminated composite. Experimental results from immersed samples, varying both the direction of measurement and the fibre volume fraction are given according to the water uptake, and leading to the characterisation of moisture expansion coefficient.