Effective medium theory for embedded obstacles in elasticity with applications to inverse problems

TL;DR

This paper develops an effective medium theory to approximate embedded obstacles in elastic media, providing rigorous estimates and applications to inverse boundary and scattering problems involving buried obstacles.

Contribution

It introduces a novel effective medium approximation for anisotropic elastic obstacles, with rigorous validation and applications to challenging inverse elastic problems.

Findings

Effective approximation of obstacles by isotropic media.

Rigorous estimates confirming the approximation accuracy.

Applications to inverse boundary and scattering problems.

Abstract

We consider the time-harmonic elastic wave scattering from a general (possibly anisotropic) inhomogeneous medium with an embedded impenetrable obstacle. We show that the impenetrable obstacle can be effectively approximated by an isotropic elastic medium with a particular choice of material parameters. We derive sharp estimates to rigorously verify such an effective approximation. Our study is strongly motivated by the related studies of two challenging inverse elastic problems including the inverse boundary problem with partial data and the inverse scattering problem of recovering mediums with buried obstacles. The proposed effective medium theory readily yields some interesting applications of practical significance to these inverse problems.