  In this paper, we establish well-posed boundary and interface conditions for
the relaxed micromorphic model that are able to unveil the scattering response
of fully finite-size metamaterials' samples. The resulting relaxed micromorphic
boundary value problem is implemented in finite element simulations describing
the scattering of a square metamaterial's sample whose side counts 9 unit
cells. The results are validated against a direct finite element simulation
encoding all the details of the underlying metamaterial's microstructure. The
relaxed micromorphic model can recover the scattering metamaterial's behavior
for a wide range of frequencies and for all possible angles of incidence, thus
showing that it is suitable to describe dynamic anisotropy. Finally, thanks to
the model's computational performances, we can design a metastructure combining
metamaterials and classical materials in such a way that it acts as a
protection device while providing energy focusing in specific collection
points. These results open important perspectives for the short-term design of
sustainable structures that can control elastic waves and recover energy.
