Fiber Bragg grating (FBG) hybrid sensors and thermocouples measure strain and temperature simultaneously during and after cure of asymmetric cross-ply composite laminates. FBG strain sensor is used to measure strain; FBG temperature sensor and thermocouple are used to measure temperature. The characteristic matrix of the sensor is derived analytically and measurements can be done without sensor calibration experiments. A wavelength-swept fiber laser is used as the light source. Two FBG hybrid sensors and two K-type thermocouples are embedded in a carbon/epoxy asymmetric cross-ply composite laminate in different directions and different locations. The real-time measurement of fabrication strains and temperatures is performed at two points within the asymmetric composite laminate during the cure process in a hot press. Through these experiments, FBG hybrid sensors are proven to be an efficient choice for smart monitoring of composite structures.
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