声学超材料等效参数测量的教学实验设计

Experimental Measurement of the Equivalent Parameters of the Acoustic Metamaterials

针对声学超材料(AMs)等效参数测量问题,设计了一种“Four-load”测量方法,并结合S-参数反演,计算等效声学参数(密度、体积模量、折射率和声阻抗)。该教学实验以Mie共振单元为实验对象,包含声信号的生成、传输、采集以及处理过程,结合理论仿真结果探讨超常规的声学特性。结果表明,实验结果与理论仿真结果相符。

Acoustical metamaterials(AMs)are composed of complex internal structures,therefore,their acoustical properties are represented by the effective parameters,such as effective mass density,bulk modulus,refractive index and acoustical impedance.To obtain these effective parameters,a“Four-load”experimental method is proposed.Combining this method and S-parameter retrieving algorithm,the reflectance,transmittance and effective parameters of the AMs can be calculated by the measured data.During this synthetical experiment,the students are brought to the frontier of scientific research by learning the generation,propagating,acquisition and procession of the acoustical signal.This experiment can fully foster the initiative and creativity of the students.