Array Analysis of Membrane-Type Acoustic Metamaterials Inspired by Spider Web-Inspired Model

Membrane-type acoustic metamaterials (MAMs) are lightweight materials with excellent low and medium frequency acoustic properties. The typical MAM array process involves using the original single cells as-is. However, practical applicatiossns often require adjusting the size of the cells to fit the actual array area, and few studies have investigated how to determine the appropriate cell size for a given array area. In this study, we selected the spider web model, which has good noise reduction properties at low and medium frequencies between 80–1600 Hz, for array analysis. We investigated the effect of denser arrays on the noise reduction performance (sound transmission loss, STL) of the spider web MAM by comparing the STL of 1 × 1, 2 × 2, and 3 × 3 array models with the same area. Simulation results showed that as the array density increased, the frequency range where the peaks of the STL occurred tended to expand. In the 2 × 2 array model, the free frame contributed to anti-resonance, resulting in a significant high noise reduction region below 700 Hz. This study contributes to the determination of optimal density for practical MAM applications and provides insight into the problem of scale variation in other acoustic metamaterials during the array process.