Research On Acoustic Control Of Acoustic Metasurface Based On Periodic Change Of Impedance

Acoustic metasurface is the product of the thin and light design of metamaterials.In view of the complicated structure of metasurfaces designed in the past and mostly used in air,this paper proposes an acoustic metasurface based on periodic change of impedance.The research on the control characteristics of underwater acoustic waves on the surface is of great significance for improving the detection performance of sonar and the acoustic stealth ability of submarines.According to the generalized Snell’s law,an acoustic metasurface based on periodic change of impedance is designed,which can realize the abnormal reflection of sound waves.According to the plane wave expansion method,the scattering of sound waves on the periodic interface is analyzed,and explain the phenomenon that the sound waves are incident on the periodic interface will excite multi-order scattered waves in space,and the generalized Snell’s law is revised.Using the concept of angular spectrum,the acquired incident sound pressure data and scattered sound pressure data are spatially Fourier transformed and compared to obtain the intensity of sound waves in various directions.This method is used to verify the phenomenon that when the sound waves are incident on the periodic interface,multi-order scattered waves are excited in space at the interface and solves the problem that the reflection angle and amplitude of each order scattered wave cannot be obtained in the simulation.The acoustic metasurface based on periodic change of impedance designed in this paper was used to verify the feasibility of abnormal acoustic wave reflection from theory and simulation,and the period width,acoustic wave incidence angle,element arrangement order,element impedance,number of elements in the period,and frequency pair were studied.The acoustic metasurface based on periodic change of impedance designed in this paper is used to realize the negative reflection of sound waves under all incident angle.Finally,related metasurface samples were prepared,the abnormal reflection characteristics of the samples under normal incidence of sound waves were verified in the pool,and the abnormal reflection phenomena under different impedances and widths were compared,which provided the theory and experimental research foundation for the practical application of acoustic metasurfaces in engineering.