Sensing characteristics of FBG sensor embedded in CFRP laminate

Sensing characteristics of FBG sensor embedded in carbon fiber reinforced polymer (CFRP) laminate were experimentally investigated in this work. In order to evaluate the monitoring accuracy, two upper/lower surface bonded FBG sensors were also included as the measurement references. Results reveal that the wavelength of embedded FBG changes sensitively corresponding to the temperature or strain variation during the experiments: responses to temperature and static loads follow highly linear trend, showing a good agreement with that of surface bonded FBGs, while the frequency responses to low velocity impact give the same resonant frequency but lower amplitudes compared with the ones of surface bonded FBGs. This work confirms that embedded FBG sensor can effectively and reliably monitor the inner conditions of composite materials. Due to the advantages of precise measurement, small size, easy integration and so on, the embedded FBG sensors have broad application prospects in the field of intelligent composites.