Sound absorption performance of auxetic star-shaped metastructure based on Helmholtz resonator and micro-perforated panel absorber
Meng Li Xue, Yi Qu, Yi Zhang, Gui Lei Chen, Wei Jiang, Tong Cheng, Ze Du, Cheng Shen, Xin Ren
Abstract
Abstract Low-frequency broadband sound absorption is a hot topic in the field of acoustics. For the Helmholtz resonator, the low-frequency sound wave can be controlled by adjusting the size of the structure. However, the frequency bandwidth of the sound absorption is narrow. The micro-perforated panel (MPP) absorber predominantly targets mid-to-high frequency noise. To achieve broadband sound absorption, an auxetic star-shaped metastructure (ASM) based on the Helmholtz resonator and MPP absorber is proposed. The ASM employs an auxetic star-shaped structure as a unit cell, wherein triangular cavities formed at the junction of the unit cells are strategically designed to function as MPP resonators. Firstly, the theoretical formula of the ASM is derived by electro-acoustic analogy, and the numerical simulation results are compared with the theoretical results. Besides, the sound absorption mechanism of the ASM is studied by the acoustic pressure distribution, particle vibration velocity distribution, and power dissipation density distribution. Secondly, the sound absorption performance of the ASM is studied by adjusting the structural parameters. Finally, it is proved that when the thickness of the ASM structure is only 40 mm, the average sound absorption coefficient of 0.9 at 580–1150 Hz. In this paper, a novel method is presented for designing a broadband sound-absorbing metastructure.