Scattering of Elastic Waves by Inclusions Surrounded by Thin Interface Layers

Abstract

The problem of scattering of elastodynamic waves by elastic inclusions surrounded by interface layers is one which is of interest for ultrasonic nondestructive evaluation of interfaces in composites. In the present paper we study scattering by a single elastic inclusion with a thin interface layer in an elastic matrix. The thin interface layer is modelled as an elastic shell, the equation of motion of which enters the boundary condition on the surface of the elastic inclusion. The scattering problem is solved by means of the null field approach, and the results are compared with those that have recently been obtained [1] by the use of a hybrid finite element and wave funtion expansion technique. Numerical results are presented showing the dependence of the scattering cross section on frequency and the elastic properties of constituents. Results show significant dependence on parameters containing the thickness, density, and stiffnesses of the interface layer.