Models for resonant acoustic metasurfaces with application to moth wing ultrasound absorption

• DOI: 10.1098/rsta.2022.0005
• Publication Date: 2022-10-09T23:05:38Z
• Authors: Yao-Ting Wang; Zhiyuan Shen; Thomas R. Neil; Marc W. Holderied; Elizabeth A. Skelton; Richard V. Craster
• Keywords: Articles; Acoustics; Moths; 530; 01 natural sciences; sound absorber; 620; metasurface; moth wing; 0103 physical sciences; Animals; Computer Simulation; acoustics; spring-mass model

Taking as bioinspiration the remarkable acoustic absorption properties of moth wings, we develop a simple analytical model that describes interaction between pressure fields, and thin elastic plates incorporating resonant sub-structures. The wing is an exemplar natural metamaterial; wings are deeply subwavelength in thickness at frequencies interest, broadband tiny scales resonate on acting concert. simplified incorporates only essential physics idealized to flat rigid rectangular coupled via spring plate forms wing; all components deep-subwavelength desired frequencies. Based Fourier analysis, complemented by phenomenological modelling, our theory shows excellent agreement with simulation mimicking moth-wing structure. Moth operate sound absorbers employing range scale sizes. We demonstrate random distribution sizes generates spectrum. To further illustrate potential model, design sub-wavelength counterpart electromagnetically induced reflectance. This article part theme issue ‘Wave generation transmission multi-scale complex media structured metamaterials (part 2)’.