| Abstract: | A study was conducted to evaluate, improve and optimize ultrasonic techniques for the detection of disbonds in composite laminate-to-metal joints. Four graphite/epoxy laminates joined to metal plates were investigated using matched pairs of compression and shear wave ultrasonic transducers of three frequencies (1,2.25, and MHz). Pulse-echo and through transmission modes were used and A-scans, C-scans and frequency spectra were analysed. It was found that the higher frequency (5 MHz) compression wave transducer operated in the through transmission mode gave the best results in most cases. Shear wave transducers were found to be cumbersome to use and unsuitable for the cases studied. |
