Timoshenko-Ehrenfest Beam-Based Reconfigurable Elastic Metasurfaces for Multifunctional Wave Manipulation

Herein, a Timoshenko-Ehrenfest beam-based reconfigurable elastic metasurface is introduced that can perform multifunctional wave phenomena within a single substrate, featuring high transmission in the ultrabroadband frequency range. Conventional elastic metasurfaces are typically limited to specific purposes and frequencies, thereby imposing significant constraints on their practical application. The approach involves assembly-components with various geometries on a substrate for reconfigurability, enabling to easily control and implement multifunctional wave phenomena, including anomalous-refraction, focusing, self-acceleration, and total-reflection. This is the first study on elastic metasurfaces to theoretically analyze the dispersion relation based on the Timoshenko-Ehrenfest beam theory, which considers shear deformations and rotational inertia. The analytical model is validated by demonstrating an excellent agreement with numerical and experimental results. The findings include full-wave harmonic simulations and experimentally visualized fields for measuring various wave modulations. Furthermore, the practicality of the system is verified by significantly enhancing the piezoelectric energy harvesting performance within the focusing configuration. It is believed that the reconfigurable elastic metasurface and analytical model based on the Timoshenko-Ehrenfest beam theory have vast applications such as structural health monitoring, wireless sensing, and Internet of Things. A Timoshenko-Ehrenfest beam-based reconfigurable elastic metasurface (TREM) is explored for multifunctional wave modulation. The metasurface is reconfigured by replacing assembly-components with various heights to impart distinct phase-shift abilities. The unit cell of the metasurface is analytically investigated based on the Timoshenko-Ehrenfest beam theory. Additionally, to verify the practicability of the metasurface, highly amplified piezoelectric energy harvesting performance is achieved in the focusing configuration. image