The influencing parameters on the sound insulation performance of membrane-type acoustic metamaterials with central local resonator

Membrane-type Acoustic Metamaterials (MAMs) effectively control low-frequency sound, surpassing conventional materials with excellent insulation capabilities. Remarkably, acoustic metamaterials with negative dynamic mass density exhibit a significant increase in sound transmission loss (STL) within a narrow frequency range. In general, the performance of material insulation involves examining factors such as dip and peak frequencies, and bandwidths of STL curves. Moreover these factors can be precisely tuned by adjusting membrane and resonator physical properties, demonstrating the adaptability of MAMs. In this study, employing parametric analysis using COMSOL Multi physics software with impedance tube testing method, the impact of parameters such as local resonator (disk) mass, resonator radius, membrane pre-tension, and membrane thickness on the performance of sound insulation by these metamaterials was investigated. Sensitivity analysis was employed to assess the impact of various parameters on the metamaterial s insulation performance. The sensitivity analysis results indicate that the first dip frequency is most sensitive to the resonator mass, decreasing by 19.5% from its initial value with an increase in resonator mass. The second dip frequency, peak frequency, and bandwidth are most sensitive to the resonator radius, increasing by 26.5%, 58.3%, and 74.7% of their initial values, respectively, with an increase in radius. It is worth noting that membrane thickness has no effect on the first dip frequency, peak frequency, and bandwidth. Therefore, considering various needs in industries, residential buildings, etc., for sound insulation purposes, optimizing insulation within a desired frequency range can be achieved by adjusting the noted influential parameters of metamaterials according to specific requirements.