Through-Transmission/Pulse-Echo Ultrasonic Equipment Evaluation.

A literature search was conducted to identify commercially available ultrasonic equipment for nondestructive inspection of bonded structures used in advanced high performance aircraft for flaws such as delaminations, debonds, and impact damage. More than fifty instruments were identified from the search. The majority approximately 20 percent of the instruments are based on other techniques such as resonance, acousto-ultrasonic, and so-called shadow techniques. Approximately forty instruments were evaluated, based on the data available from the literature, for their capabilities and limitations. A trend toward the digital, automatic, and computer-controlled instruments was observed. The majority of the commercial instruments are microprocessor-controlled with interfaces for communication with other devices such as an external computer, a printer, a recorder, or a video display. Also, the majority of the instruments are modular in construction to facilitate maintenance and repair. In addition, almost all instruments are equipped with visual andor audible alarms.