Deflecting incident flexural waves in a cylindrical shell metasurface

Nowadays, most research in metasurfaces focuses on flat plates, while curved plates widely used in engineering structures and lack sufficient corresponding research on elastic wave propagation mechanisms. In this paper, transmission properties of incident flexural waves in cylindrical shell metasurface with different curvatures are researched, and the flexural wave modulation is accomplished by accumulation of specific phase shifts. To start with, the metasurfaces cell model composed of curved cylinder is constructed in subwavelength range, the transmittance and phase of flexural wave at different curvatures were analyzed by using finite element method. Then, the supercells with special geometric dimensions are selected to combine into a complete cylindrical shell metasurfaces according to the generalized Shell law, and the approximate deflection formulas of flexural waves with different curvatures are obtained by curve fitting. Finally, the accuracy of incident flexural wave modulation is verified by the comparative results of simulation and experiment. The results show that there is a special functional relationship between curvature and phase, the deflection angle of flexural wave on metasurface is similar to the predicted values. From this paper, it is known that the change of phase shift decreases with the increase of curvature, the above formulas can not only be used for cylindrical shells with different curvatures, but also ensures high transmittance and full phase control. Therefore, this work may have a wide range of potential applications in the fields of vibration control, ultrasonic guidance, energy collection and sound stealth.