Steering and focusing of fundamental shear horizontal guided waves in plates by using multiple-strip metasurfaces

We proposed a metasurface consisting of multiple parallel strips with varied widths which can steer and focus the fundamental shear horizontal (SH0) wave in plates. Firstly, the group velocity of the quasi-SH0 wave in different-width strips was calculated. Then, a multiple-strip metasurface was designed which was realized by through-thickness grooving in an aluminum plate. Finite-element simulations show that this metasurface can steer the SH0 wave to a prescribed angle. Later, experiments were conducted in which thickness-shear (d15) piezoelectric strips were used as SH0 wave exciters and receivers, and experimental results well reproduced the simulation results. Finally, another multiple-strip metasurface was designed to focus the SH0 wave at a designated point. Both simulations and experiments were conducted, and results validated the proposed design. This work may provide guidance for the design of SH wave metasurfaces