Damage detection in composite materials by FBGs

Embedded fiber Bragg gratings (FBGs) are sensitive to changes of near strain fields in a composite host monolithic structure, typical of aircraft airframes. FBGs have been embedded in different configurations (a typical position is the skin -- stiffener interface in a monolithic structure) for detecting events associated to damage occurrence. Thus, it is possible to think in FBGs not only as strain sensors, in a classical load monitoring configuration, but as a part of a structural health monitoring (SHM) system in composite structures dimensioned following damage tolerance criteria.