基于分形曲线和空间卷曲的理念设计出一种声学超材料，具有小尺寸调控大波长的特点。利用等效参数法提取了该超材料的等效质量密度和体积模量，在特定的频率点处，这种声学超材料具有近零密度特性，可以实现声波的零相位差传播和能量无损耗传输。基于有限元法分析表明：在近零密度频率点处，该声学超材料可以实现特殊的声学现象如声隐身、声隧穿、波前整形和声异常透射。最后，测试了加工样品的透射系数，结果表明：实验数据与仿真计算结果符合较好，验证了结构的有效性，表明该声学超材料可以用于声学器件的设计。
Abstract
An acoustic metamaterial is designed based on the concept of fractal curve and spatial coiling, which has the characteristics of small size regulating large wavelength. The equivalent mass density and equivalent volume modulus of the metamaterial are extracted by the equivalent parameter method. At a specific frequency point, the acoustic metamaterial has the characteristic of near zero density, which can realize the zero-phase difference propagation and lossless energy transmission. The finite element analysis shows that the acoustic metamaterial can achieve special acoustic phenomena such as acoustic cloaking, acoustic tunneling, wavefront shaping and acoustic abnormal transmission at near zero density frequency points. Finally, the transmission coefficient of the sample is tested, and the results show that the experimental results are in good agreement with the simulation results, which verifies the validity of the structure, and indicates that the acoustic metamaterial can be used in the design of acoustic devices.
关键词
近零折射率 /
声学超材料 /
声隧穿 /
声隐身
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Key words
Near zero refractive index /
Acoustic metamaterial /
Acoustic tunneling；Sound cloaking
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