4. Scattering Theories Available for Future Application
At high frequencies, the geometrical theory of diffraction provides useful and relatively simple approximations to diffracted fields. In this paper the theory is applied to the diffraction of time-harmonic longitudinal waves by a penny-shaped crack in an elastic solid.
Achenbach, J. D.; Gautesen, A. K.; and McMaken, H., "Application of Geometrical Diffraction Theory to Scattering by Cracks" (1978). Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE, September 1976–June 1977. 18.