Patent ID: 7283693

Claim:
A method of monitoring structural damage in a composite structure manufactured by co-curing, co-bonding or secondary bonding of several sub-components ( 7 , 8 ), using fibre optic Bragg grating sensors attached or embedded to or between (in the bonding line) said sub-components, characterised by comprising the steps of: a) measuring the wavelength spectra ( 31 , 33 , 40 ) of said Bragg grating sensors at the end of the manufacturing of the part, and in a known load condition, considered as reference; b) identifying the occurrence of a failure of the structure and the progress of said failure detecting the release of the residual stresses/strains stored during the curing process by measuring changes ( 31 to 32 , 33 to 34 , 40 to 41 ) with respect to said reference wavelength spectra.