Experimental demonstration of a three-dimensional omnidirectional and broadband acoustic concentrator using an anisotropic metamaterial  

作　　者：ChengBo Hu Bin Liang Jing Yang JianChun Cheng 

机构地区：[1]Key Laboratory of Modern Acoustics,Ministry of Education,Institute of Acoustics,Department of Physics,Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2021年第4期17-24,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Key R&D Program of China(Grant No.2017YFA0303700);the National Natural Science Foundation of China(Grant Nos.11634006,11374157 and 81127901);a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。

摘　　要：We report the theoretical design and experimental demonstration of a three-dimensional(3D)omnidirectional and broadband metamaterial-based concentrator for airborne sound.The proposed mechanism uses a homogeneous anisotropic acoustic metamaterial with an ellipsoidal equifrequency contour to efficiently redirect the acoustic energy impinging on its outer surface into the central region,regardless of the incident direction.A design of the metamaterial unit cell is proposed as a practical implementation of our strategy,which is simply realized by perforating a solid spherical shell with a linearly shrinking cross section in the radial direction.We analytically and numerically prove that the non-resonant anisotropic effective acoustic parameters required for building the concentrator are produced with such a design.Good agreement is observed between the theoretical predictions and experimental measurements.An effective concentration of the incident acoustic energy is observed within a broadband that ranges 1000-1600 Hz.The experimental realization of this 3D acoustic concentrator with a simple design,low energy loss,replaceable constituent material,and omnidirectional and broadband functionality offers new possibilities for acoustic manipulations and may have important applications in a plethora of scenarios ranging from energy harvesting to noise mitigation.

关 键 词：acoustic concentrator anisotropic metamaterial perforated hemispherical shell 

分 类 号：TB34[一般工业技术—材料科学与工程]