Porosity Estimation of Composites Using Acoustic Attenuation

Ultrasonic techniques for measuring void content were discussed and the composites used for the whole fuselage composite aircraft AG300 were chosen as experimental specimens, including 10 unidirectional carbon fiber laminates and 10 textile glass fiber sheets. The ultrasonic RF signals were processed using Hilbert transform and spectral-filter and then used to calculate the acoustic attenuation. The relationship between attenuation coefficient and porosity was calibrated by sampling experiment based on metalloscope. The calibrated formula was then used to estimate the porosity of the rest specimens. The results indicate that the porosity values estimated by the calibrated formula are in good agreement with the values determined by metalloscope.