Swept Frequency Ultrasonic Imaging in Composite Plates

Conventional ultrasonic C-scan imaging normally employs focussed transducers excited by high-voltage impulsive signals. The reflected wave train, containing information about the internal features of the test piece, is translated, either through analog or digital means, to an intensity (or color) and plotted as a function of transducer position on the sample. While this method is certainly effective for many inspections, it is not the only way, or perhaps even the best way, to obtain this kind of information. The purpose of this paper will be to describe an alternate means to acquire ultrasonic C-scan data using a swept-frequency tone-burst imaging technique which presents several important advantages over more conventional means