Wave Propagation in a Plate with Defects

Abstract

A significant number of commercial and military airplanes currently in service have exceeded their design service lives. It is of great importance to monitor the initiation and propagation of flaws in such aging aircraft structures to ensure their safety and integrity. This paper is concerned with the nondestructive evaluation of corrosion cracks emanating from rivet holes in typical aircraft structural components. Conventional NDE techniques require point-by-point inspection, a time-consuming and often unreliable process. Guided waves, which direct wave energy along the plate, carry information about the status of the material in their path and offer a more efficient tool for the inspection of structural components. Using a pitch-catch technique, with one transducer as a transmitter wave and two or more transducers as receivers placed at different positions around the rivet hole, guided waves can be launched and detected to inspect plate-like structures, line by line, thus increasing the inspection efficiency significantly. By studying the characteristics of the received signals, information about the condition of the rivet holes can be obtained.