Scattering of SH waves by flaws in sandwich plates and its use in flaw detection

The strip element method (SEM) is used to investigate SH wave scattering by rectangular flaws in sandwich plates. The plates containing flaws are divided by junctions into domains in which the SEM is applied. For each domain, SEM equations for anti-plane motion are derived. These equations give a relationship between the traction and displacement vector on the vertical boundaries. A set of equations which give a relationship between the traction and displacement vector on the junctions is then obtained by assembling the SEM equations for all the domains. This set of equations is solved by using the conditions on the junctions. Scattered SH wave fields in the frequency domain for sandwich plates with rectangular flaws are computed and discussed in comparison with results for corresponding plates without flaws. A technique for determining the length and the damage factor of a rectangular flaw in a sandwich plate is also presented.