Broadband low-frequency sound absorption by coiled-up space embedded in a porous layer

Low frequency noise has strong penetration power and is difficult to be attenuated. In order to solve the problem of low-frequency noise absorption in traditional sound absorbing materials, a coupled structure of coiled-up space core embedded in a porous material (CSPM) is proposed. The coiled-up space core (CSC) structure consists of a folding structure and a labyrinth structure, and a rectangular slot is cut at the top of each structure to allow the sound wave to enter. The resonant sound absorption peak of CSPM is formed in the low frequency range and the sound absorption performance is achieved above 85% at 105 Hz and 90% at 315 Hz. The CSMPs which consists of four different parameters of CSC embedded in the porous layer, and its absorption performance can reach as high as 0.75 from 195 Hz to 600 Hz. The influences of the porosity, flow resistance, tortuous factor of porous materials and parameters of CSC on the sound absorption performance are also investigated. In this work, CSPM is fabricated and its sound absorption performance is tested through an impedance tube for verifying the correctness of the simulation. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The CSPM structure utilizes a coiled-up space core embedded in a porous material to achieve low frequency noise absorption, achieving sound absorption performance of over 85% at 105 Hz and 90% at 315 Hz.