On the application of the Wiener-Hopf technique to problems in dynamic elasticity

Abrahams, I. David (2002) On the application of the Wiener-Hopf technique to problems in dynamic elasticity. Wave Motion, 36 (4). pp. 311-333. ISSN 0165-2125

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Abstract

Many problems in linear elastodynamics, or dynamic fracture mechanics, can be reduced to Wiener–Hopf functional equations defined in a strip in a complex transform plane. Apart from a few special cases, the inherent coupling between shear and compressional body motions gives rise to coupled systems of equations, and so the resulting Wiener–Hopf kernels are of matrix form. The key step in the solution of a Wiener–Hopf equation, which is to decompose the kernel into a product of two factors with particular analyticity properties, can be accomplished explicitly for scalar kernels. However, apart from special matrices which yield commutative factorizations, no procedure has yet been devised to factorize exactly general matrix kernels. This paper shall demonstrate, by way of example, that the Wiener–Hopf approximant matrix (WHAM) procedure for obtaining approximate factors of matrix kernels (recently introduced by the author in [SIAM J. Appl. Math. 57 (2) (1997) 541]) is applicable to the class of matrix kernels found in elasticity, and in particular to problems in QNDE. First, as a motivating example, the kernel arising in the model of diffraction of skew incident elastic waves on a semi-infinite crack in an isotropic elastic space is studied. This was first examined in a seminal work by Achenbach and Gautesen [J. Acoust. Soc. Am. 61 (2) (1977) 413] and here three methods are offered for deriving distinct non-commutative factorizations of the kernel. Second, the WHAM method is employed to factorize the matrix kernel arising in the problem of radiation into an elastic half-space with mixed boundary conditions on its face. Third, brief mention is made of kernel factorization related to the problems of flexural wave diffraction by a crack in a thin (Mindlin) plate, and body wave scattering by an interfacial crack.

Item Type:	Article
Uncontrolled Keywords:	Elastic waves; Wiener–Hopf technique; Matrix Wiener–Hopf equations; Scattering; Diffraction; Acoustics; Geometrical theory of diffraction; Padé approximants; Non-destructive testing
Subjects:	MSC 2010, the AMS's Mathematics Subject Classification > 30 Functions of a complex variable MSC 2010, the AMS's Mathematics Subject Classification > 43 Abstract harmonic analysis MSC 2010, the AMS's Mathematics Subject Classification > 46 Functional analysis MSC 2010, the AMS's Mathematics Subject Classification > 47 Operator theory MSC 2010, the AMS's Mathematics Subject Classification > 78 Optics, electromagnetic theory MSC 2010, the AMS's Mathematics Subject Classification > 81 Quantum theory
Depositing User:	Professor I D Abrahams
Date Deposited:	26 Nov 2006
Last Modified:	20 Oct 2017 14:12
URI:	https://eprints.maths.manchester.ac.uk/id/eprint/420

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