Detection of defects in as manufactured GFRP–GFRP and CFRP–CFRP composite bonded joints using chirped fibre Bragg grating sensors

Chirped fibre Bragg grating (CFBG) sensors have been embedded in composite coupons which have been used to form one half of single lap bonded joints. The bonded joints have been made with deliberately included defects, consisting of either a PTFE insert or an air gap, and the sensors have been used to detect the presence and location of the defects. The experimental results, and the modelling, show that defects in both GFRP–GFRP joints and CFRP–CFRP joints can be detected by the embedded CFBG sensors, though it is easier to detect defects in the lower stiffness (GFRP) joints.