Experimental and FEA evaluation of membrane-type locally resonant acoustic metamaterial arrays for aircraft interior sound insulation

摘要

Metamaterials have emerged as promising solutions for manipulation of sound waves in a variety of applications. Locally resonant acoustic materials (LRAM) decrease sound transmission by 500 % over acoustic mass law predictions at peak transmission loss (TL) frequencies with minimal added mass, making them appealing for weight-critical applications such as aerospace structures. TL of single-celled and multi-celled LRAM was measured with systematic variation in geometric parameters to understand the effects of each parameter on acoustic response. FEA was also used to predict TL as a function of frequency for structures with varying complexity. Stacked LRAM panels were evaluated to produce structures with both increased TL magnitude and multi-peak profiles. Finally, dynamic response of the single-cell and array structures under discrete frequency excitation was examined using laser vibrometry to understand the mechanism of sound insulation and to verify negative dynamic mass behavior.