The Tmatrix for Elastic Scattering by a Partly Closed Circular Crack

The object of this work is to calculate the T (transition) matrix for a circular crack in a homogeneous, isotropic, linear elastic medium. The T matrix method is a building block technique for multiple scattering, where the T matrix is calculated for each scatterer separately without prior knowledge of the other scatterers (cracks, inclusions, surfaces, etc.).This means that we solve the scattering problem for arbitrary incoming time harmonic elastic waves. A solution for the scattering by an open circular crack can be found in [1], and for multiple scattering see [2]. On the cmck surface the so called spring contact boundary conditions are assumed, enabling modelling of various cracktypes, such as the open crack, the fluid filled crack and a crack partly closed by a static background pressure. Numerical calculations of the scattering cross sections and the crack-scattered farfield amplitudes for incoming plane waves are given.