Adhesively bonded joints between two plates are gradually receiving increasing acceptance in safety-critical structures, and therefore methods for nondestructive evaluation (NDE) of adhesive joints have drawn much attention. In this paper, specimens with lap splice joints are prepared for the purpose of guided-wave-based debonding damage detection. Fibre optic Doppler (FOD) sensors are used to acquire guided ultrasonic waves propagating in two kinds of bonded specimens, namely aluminium and carbon fibre reinforced plastic (CFRP) assemblies. To overcome the drawbacks of sensor networks in conventional structural health monitoring systems, a self-calibration sensor network is constructed based on elastic analyses of the bonded structures. By using the proposed sensor network, both the baseline measurement and the defect-related guided wave signals can be acquired in one excitation experiment. Moreover, complicated signal interpretation is also avoided by using the simplest feature, arrival time, of the ultrasonic wave signals.
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