A Novel Ultrasonic B-Scan Technique For One-Sided Inspection Of Thick Composites With Complex Surface Shapes

A high power low frequency, frequency bandwidth control ultrasonic sector B-scan system with specially designed sector scan transducers is proposed for the internal or under water one-sided inspection of thick (at least 3") composite components with complex surface shapes. This technique is based on the following considerations for ultrasonic NDT of thick composite components: high attenuation, low signal-to-noise ration (s/n), and anisotropy. Low frequency and high power along with specially designed transducers can increase the penetration capability of the ultrasonic waves. An effective computer program, split spectrum processing (SSP), will also be applied to this technique to increase s/n. The sector B-scan in different directions provides information about fiber orientation as well as defects. Transducers with a special soft front plate to match the complex shape surfaces of the composite components will be designed. The sensitivity and resolution of this system will be further examined. It is anticipated that the defects of dimension of 10 mm or less be detected.