A 3D-printed sound-absorbing material based on multiple resonator-like unit cells for low and middle frequencies

Abstract

Inorganic fiber-based porous materials, such as glass and rock wool, are cost-effective, light weight, and currently make up the most commonly used sound-absorbing materials. However, the performance of these materials degrades owing to moisture, weather, and gravity. Porous materials have difficulty absorbing low-frequency sounds. In these cases, resonator-type sound-absorbers are used, but the target frequency is narrow. Thus, a novel sound-absorbing material that solves these issues is desired. Recently, the advancement of additive manufacturing enabled the realization of complex structures, and artificial acoustic materials have attracted significant attention. This study conducted numerical, theoretical, and experimental investigations to develop novel sound-absorbing materials with desired sound absorption properties based on a flexible situation. These materials also address aforementioned problems in conventional inorganic porous materials and resonators. Results suggest that the periodic structures based on resonators and their combination are good sound-absorbers for low- and middle-frequency ranges, exploiting the properties of each structure.