Non-destructive testing of composites

Abstract Materials and manufacturing anomalies are inherent in composites and therefore introduction of composites into large scale production depends in large measure on the successful application of non-destructive testing (NDT) techniques for monitoring. It should also be appreciated that for wide acceptance of various NDT techniques, they should be positive in results, economical to procure and easy to apply. In view of this, a number of NDT techniques were evaluated for their applicability to assess internal features such as voids, fibre volume fraction, fibre wash or misoriented fibres, interlaminar and translaminar cracks, lay-up orders, latent defects etc, in fibre-reinforced plastics composites. The NDT techniques employed included x-radiography, ultrasonics, eddy-current methods, photometry and x-ray diffractometer, and acoustic emissions.