Switchable multifunctional knob elastic metasurface for arbitrary modulation of flexural waves

Manipulating elastic waves propagating in the desired manner has attracted substantial attention, and the metasurfaces offer the important ideas to achieve this goal. In particular, it will be more advantageous if wave function switching can be achieved without changing the microstructure of the metasurface. In the paper, a knob elastic metasurface is designed to realize the regulation of flexural wave covering the 0-2 pi range of phase shift by rotating the angle of the knob. When the metasurface is in the turn-on state, the angles of the knob at different positions can be adjusted reasonably though the generalized Snell's law to achieve several phenomena of anomalous refraction, beam focus, and non-paraxial self-acceleration of flexural wave in a wide frequency. And when the metasurface is placed in the turn-off state, the total reflection of the flexural wave can be realized, and then bidirectional vibration isolation can be achieved.