Nondestructive Evaluation Of Composite Part Details Using Digital Acoustic Video Evaluation

The universal applicability of ultrasonic inspection to aircraft components has helped establish it as an essential nondestructive method. Composite detail parts such as attach pieces, stiffeners, and intercostals generally undergo manual contact ultrasonic inspection due to their complex shapes and relatively small size. These manual inspections involve scanning transducers as small as 0.635 cm (0.25 inch) in diameter across the part surface in order to provide 100% inspection coverage. These inspections are labor-intensive, tedious, and costly in terms of the time involved. Usually, the anomalies and defects associated with these parts are relatively simple to characterize, with the radius areas being the most difficult. Digital acoustic video evaluation essentially provides an ultrasonic "camera" capable of much broader coverage than the conventional transducer arrangement. This inspection is performed by placing the part in a tank of water while articulating it between a relatively large transducer and the digital acoustic camera. The results can then be viewed in real time. This method is, of course, faster than the conventional manual pulse-echo ultrasonic method by several times. In this paper, we will give the results of a study involving several part details having varied types of defects. We will also demonstrate the congruency between the conventional method and the digital acoustic video method as far as sensitivity is concerned. This is a major factor when deciding whether the faster method should replace the slower one.