Forward ultrasonic scattering from multidimensional solid or fluid inclusions buried in multilayered elastic structures

摘要

The scattering of elastic waves by multidimensional objects buried in a multilayered elastic background medium insonified by ultrasonic forces is studied. The framework developed is based on an integral equation formalism for elastic scattering, where a Born approximation for an inhomogeneous background medium is applied to obtain a closed-form expression for the scattered field. Both compressional and shear waves are allowed to propagate inside the layers, and take into account cross-polarization at the boundaries and multiple reflections within the layers to compute the scattered field. The procedure has been tested in cases where the Born approximation is severely put to test (100% contrast in shear modulus).