Elastic Wave Diffraction at Cracks in Anisotropic Materials

Theoretical Evaluation of Ultrasonic Scattering by Flaws in Anisotropic Media

“…Since the application regime of Kirchhoff's approximation is confined to the region of specular reflection, other methods have to be applied to account for the tip reflection. Geometrical Theory of Diffraction seems to be suitable [7], work concerning a respective inclusion into the presented theory is underway.…”

G.R. Wickham: an appreciation

“…The bulk of his research articles appeared throughout the last decade reflecting his increasing expertise and enthusiasm. At the time of his death, Gerry was actively discussing a variety of research topics with collaborators from around the world: these include inverse problems in one-, two-and three-dimensional acoustics and elastodynamics (with Zhiming Sun, P. Olsson amongst others); stability of fluid-loaded elastic structures [41]; new applications of the polarization method for interfaces and thin layers (with John Harris); relevance of hyperasymptotics to wave diffraction and scattering (with colleagues at Brunel University); application of a new method for matrix Wiener-Hopf factorization [30,36] to diffraction from cracks in isotropic and anisotropic materials [34,38]; diffraction of elastic waves by an imperfect fusion bond [39]; high frequency wave propagation in inhomogeneous and anisotropic solids [40]. Much of this activity has continued since Gerry's death, as indicated in the publication list to follow, and will no doubt provide further stimulus to research in coming years.…”

Diffraction of a plane stress wave by a semi-infinite crack in a general anisotropic elastic material

“…The solution of plane wave diffraction in a cracked isotropic solid is well known [1,2]. The diffraction of a time-harmonic wave by a semi-infinite crack has been studied by Norris and Achenbach [3] for a transversely isotropic material and by Lewis et al [4,5] for an anisotropic material. A three-dimensional elastodynamic model for ultrasonic wave propagation and crack detection in anisotropic materials has been developed by Eriksson et al [6].…”