Plate-type acoustic metamaterials: Evaluation of a large-scale design adopting modularity for customizable acoustical performance

With the goal of industrial applications, the scalability of finalized designs is important. If typical membrane-type acoustic metamaterials were extended to a larger scale, manufacturing issues-stress uniformity of the membrane and spatial consistency of the platelet, for example-could arise. These issues could be addressed by plate-type acoustic metamaterials with an internal tonraum resonator, which were previously shown to be potential for noise control below 1 kHz. This study presents a large-scale design (or meta-panel) adopting modularity for customizable acoustical performance. By considering two specimen configurations-without and with resonator-the results showed that the acoustical performance of each specimen configuration could be scaled and modularly combined. The acoustical performance of the meta-panel was insensitive to the specimens' orientation and arrangement. Additionally, the meta-panel could still provide up to an average insertion loss of 12.3 dB with 4% of unoccupied slots, not to mention the broadband insertion loss at 125-400 Hz and 0.8-5 kHz, beneficial for many noise environments. Consequently, the proposed design not only could address the potential manufacturing issues of large-scale membrane-type acoustic metamaterials but also could provide customizable acoustical performance, demonstrating scalability and modularity. (C) 2019 Elsevier Ltd. All rights reserved.