Lamb Wave-based Quality Inspection of Repaired Carbon Fibre Reinforced Polymers for On-Site Aircraft Maintenance

On-site aircraft repairs are gaining in importance due to the susceptibility of carbon fibre reinforced polymers to damage. Repairs themselves are required to be inspected for quality, preferably cost- and time-efficiently. This paper presents an approach for the inspection of repaired composites based on guided Lamb waves. The focus is on cost-effective signal excitation and effective signal processing. Lamb waves are excited with piezoelectric transducers at the resonance frequency of the material under test. Measured signals are processed with a complex wavelet transform to improve damage detection. The proposed approach is evaluated on two test specimens, one of which has a defect in the adhesive bond.