An Efficient Approximate Model for Elastic Wave Scattering in Plates

Abstract

The objective of this work is to develop a fast method for modeling time-domain ultrasonic wave scattering in plates. Due to the possible excitation of multiple plate modes and dispersive behavior of these waves, the scattered signal can be very complicated. The model that is presented in the following, can be valuable tool in real-time inspection or development of new inspection techniques for the aircraft safety inspection. Inspection of the structural integrity of an aircraft involves, in part, the inspection of rivots for existence of cracks. Rivots can be checked using eddy-current probes or regular contact ultrasonic transducers. However, for inspection of rivots that are hidden by a top layer (e.g. lap-joints), a better technique may be to excite a guided ultrasonic wave which can travel in the plate under the joint and interrogates the hidden rivot. The scattered signal can be picked up by the same transducer in the pulse-echo mode.