Transfer matrix modeling and experimental validation of cellular porous material with resonant inclusions

Abstract

Porous materials are widely used for improving sound absorption and sound transmission loss of vibrating structures. However, their efficiency is limited to medium and high frequencies of sound. A solution for improving their low frequency behavior while keeping an acceptable thickness is to embed resonant structures such as Helmholtz resonators (HRs). This work investigates the absorption and transmission acoustic performances of a cellular porous material with a two-dimensional periodic arrangement of HR inclusions. A low frequency model of a resonant periodic unit cell based on the parallel transfer matrix method is presented. The model is validated by comparison with impedance tube measurements and simulations based on both the finite element method and a homogenization based model. At the HR resonance frequency (i) the transmission loss is greatly improved and (ii) the sound absorption of the foam can be either decreased or improved depending on the HR tuning frequency and on the thickness and properties of the host foam. Finally, the diffuse field sound absorption and diffuse field sound transmission loss performance of a 2.6 m 2 resonant cellular material are measured. It is shown that the improvements observed at the Helmholtz resonant frequency on a single cell are confirmed at a larger scale.

Numerical and experimental investigations on the acoustic performances of membraned Helmholtz resonators embedded in a porous matrix

“…Outside this resonance, the melamine acoustic transmission loss is improved due to the added mass of the embedded HR. This effect has been presented through experimental and numerical examples that can be found in the paper by [18]. The authors concluded that it is linked to the resonance frequency of the resonator, the hosting foam size and its acoustic properties but also to the surface ratio of each component.…”

“…Enhancement on the acoustic performances were obtained at low frequencies. Doutres et al [18] investigated theoretically, numerically, and experimentally the acoustic absorption and transmission loss performances of a porous material with HR inclusion. An analytical model based on an extended P-TMM (Parallel transfer matrix method) has been proposed and results validated with measured and FEM (finite elements method) results.…”

Recent advances in building acoustics: An overview of prediction methods and their applications

“…A number of researchers investigated the sound absorption performance of porous layers with embedded resonant inclusions [89][90][91][92][93][94][95][96]. Oliva and Hongisto [97] investigated and compared the accuracy of seven existing impedance prediction methods targeting the sound absorption coefficients of porous material.…”

Acoustic Metamaterials: A Potential for Cabin Noise Control in Automobiles and Armored Vehicles

“…Recently, the inclusion of HRs in porous material is proposed by arranging them similarly in a periodic manner [Doutres et al, 2015]. Expectedly, excellent sound attenuation is achieved but limited to the tuned resonance frequency of the resonators.…”