Re-routing of shear waves around a spherical obstacle by means of a fiber-reinforced metamaterial

Paper in proceeding, 2014

We consider a canonical spherical scattering problem, and show that by coating a rigid spherical body with a fiber-reinforced layer of a metamaterial with a suitable gradient in material properties, the scattering of shear waves from the body can be significantly reduced, as many shear modes are guided around the body without distorsion. All purely tangential spherical shear modes can be made to pass as if the sphere was not present at all in the wave field. A result of the analysis in the present study is, that to maximize number of modes to which the coated spherical body is "invisible," rigid body rotations of the innermost part of the coating should be allowed. We also give explicit examples of cases where complete knowledge of the scatterer and of the scattered field does not even remotely suffice to determine the incident field.