Guided Waves in a Plate With a Delamination-Like Discontinuity Available to Purchase

In this paper, some of the useful properties of guided Lamb waves are investigated, using analytical, numerical and experimental methods, in an effort to provide the knowledge base required for the development of viable nondestructive evaluation (NDE) systems for composite structures. An analytical frame-work that considers propagating, nonpropagating and evanescent Lamb waves to analyze the scattering of an incident ultrasonic Lamb wave at delaminations and disbonds is presented. In addition to the delamination problem, the interaction of Lamb waves with a step discontinuity, which can be found at common stiffeners, is investigated using a similar analytical approach. A near-field solution is obtained, and power flows through the cross-sections of the plate are evaluated. The agreement between experimental, numerical and theoretical results is shown to be excellent in certain frequency ranges, providing guidance for the design of reliable and effective inspection systems for modern aeronautical and aerospace structural components.