Experimental evaluation of membrane type acoustic metamaterial arrays.

Abstract

Traditional acoustic treatments such as foam and fiber panels used for sound insulation in transportation applications typically perform poorly at low frequencies without costly addition of mass. Locally resonant acoustic metamaterials have demonstrated a single transmission loss (TL) peak of up to 500% over the acoustic mass law at frequencies as low as 100 Hz with minimal weight penalty. The frequency of the TL peak was tuned by adjusting various geometric properties of the structure including membrane material, mass magnitude, and membrane size. Limits to the practical applications of the single‐cell structure resulted in the development of panels comprised of multiple mass‐weighted membranes. Arrays of membrane‐type metamaterials were fabricated and evaluated to examine their transmission loss and dynamic response under acoustic loading. Large membranes were divided using support frames to create individual cells of the metamaterial. Multiple TL peaks were achieved for the arrays by varying the mass m...