Elastic wave scattering by an inclusion in a multilayered medium submerged in fluid. I. Plane strain model

摘要

Response of plane multilayered media enclosing an elastic inclusion of arbitrary shape and submerged in fluid is investigated. The plane strain model is assumed. The steady-state free-field response is modeled by the Thomson-Haskell method using delta-matrix modification and the scattered wave field by a boundary method. The transient response is evaluated using the Fourier synthesis. Numerical results are presented for a single layer plate with an elliptical inclusion and a single layer with an inclusion bounded by an elastic half-space. For the steady-state fluid-solid interface response the results show that (i) presence of the half-space greatly influences the response; (ii) the response is very sensitive upon the geometry and the embedment depth of the inclusion; (iii) the response is sensitive upon the angle and frequency of incident wave; and (iv) impedance contrast between the plate and inclusion is important for overall response pattern. Transient results for vertical incidence demonstrate that the presence of the inclusion is detected very clearly by both predominant and nonpredominant components of motion.