RELIABILITY OF FIBER BRAGG GRATING SENSORS EMBEDDED IN TEXTILE COMPOSITES

The reliability of the fiber Bragg grating (FBG) sensors embedded in t extile composites with both dual-end and single-end is studied in this paper. The effects of debonding of the interfaces of the fiber/coatin g and coating/resin on the reliability are considered. Measurement err or induced by the deviation of the location of sensors after embedding into a composite has been analyzed for the three-point bending experi ments. The analysis indicates that the determination of the precise lo cation of FBG sensors would be a key problem when the sensors are embe dded in a large gradient strain field. The experimental results show t hat the debonding at the interfaces has great effect on the reliabilit y of single-ended FBG sensors and little effect on that of dual-ended sensors. It is suggested that FBG sensors be calibrated before they ar e imbedded into composite, which will help to improve the precision of the measurement and avoid damage to sensors to ensure the sensor's st rength while the composite is under loading.