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Modeling of acoustic porous material absorber using rigid multiple micro-ducts network: Validation of the proposed model

November 2018
Journal of Sound and Vibration 443:376–396

DOI:10.1016/j.jsv.2018.11.036

Authors:

Paulo Mareze

Federal University of Santa Maria

Eric Brandao

Federal University of Santa Maria

William D'Andrea Fonseca

Federal University of Santa Maria

Olavo M. Silva

Universidade Federal de Santa Catarina

Show all 5 authorsHide

Porous materials present many important characteristics for the field of acoustics like thermal insulation, acoustic absorption, impact insulation and lightweight. There are many situations where one can find applications, such as aeronautics, automotive industries, heat and air conditioning systems, buildings, industry in general and others. Nowadays, with advances in the material fabrication process, it's possible to create complex structures according to the final objective. In this study, the greater interest is to increase sound wave absorption for industrial or residential applications. For a complete understanding of the needed characteristics to have a good absorber, it is recommended to model the structure through geometric pore reconstruction. This is a better way to later define which direction to take in order to increase the absorption curve, as well as which modifications and geometric restrictions must be performed to manufacture the best material for a given application. Simple macroscopic or empiric analytical models can be used to describe the visco-thermal dissipation inside the material. However, this approach does not present a clear link between micro and macro properties. This study proposes the reconstruction of cellular porous media using microscopic technique images. The proposed model basically is a 2D duct network made of simple uni-dimensional acoustical cylinders or pores. The theory based on acoustic transfer matrix method and mobility matrix model has been merged with analytical visco-thermal dissipation to implement the model proposed. Two cellular materials have been experimentally validated against the surface impedance and absorption for normal incidence: melamine foam and the porous aluminum. Valid agreements have been found between the experimental and numerical data. Future experiments will investigate geometry optimization methods to increase the absorption curve in frequency bands of interest.

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Journal of Sound and Vibration 443 (2019) 376–396

Contents lists available at ScienceDirect

Journal of Sound and Vibration

journal homepage: www.elsevier.com/locate/jsvi

Modeling of acoustic porous material absorber using rigid

multiple micro-ducts network: Validation of the proposed

model

Paulo H. Mareze a,∗, Eric Brandão a, William D’A. Fonseca a, Olavo M. Silva b,

Arcanjo Lenzi b

aAcoustical Engineering, Federal University of Santa Maria, Roraima Avenue 1000, Camobi, Santa Maria, RS, 97105-900, Brazil

bVibration and Acoustic Laboratory, Federal University of Santa Catarina, Campus Universitàrio, Trindade, Florianópolis, SC, 88040-900, Brazil

article info

Article history:

Received 27 February 2018

Revised 13 October 2018

Accepted 19 November 2018

Available online 22 November 2018

Handling Editor: Y. Auregan

Keywords:

Porous materials

Sound absorption coeﬃcient

Pore micro-geometry

Visco-thermal effect

Mobility Matrix Model

Finite Element Method

abstract

Porous materials present many important characteristics for the ﬁeld of acoustics like ther-

mal insulation, acoustic absorption, impact insulation and lightweight. There are many situ-

ations where one can ﬁnd applications, such as aeronautics, automotive industries, heat and

air conditioning systems, buildings, industry in general and others. Nowadays, with advances

in the material fabrication process, it’s possible to create complex structures according to

the ﬁnal objective. In this study, the greater interest is to increase sound wave absorption

for industrial or residential applications. For a complete understanding of the needed char-

acteristics to have a good absorber, it is recommended to model the structure through geo-

metric pore reconstruction. This is a better way to later deﬁne which direction to take in

order to increase the absorption curve, as well as which modiﬁcations and geometric restric-

tions must be performed to manufacture the best material for a given application. Simple

macroscopic or empiric analytical models can be used to describe the visco-thermal dissipa-

tion inside the material. However, this approach does not present a clear link between micro

and macro properties. This study proposes the reconstruction of cellular porous media using

microscopic technique images. The proposed model basically is a 2D duct network made of

simple uni-dimensional acoustical cylinders or pores. The theory based on acoustic transfer

matrix method and mobility matrix model has been merged with analytical visco-thermal

dissipation to implement the model proposed. Two cellular materials have been experimen-

tally validated against the surface impedance and absorption for normal incidence: m elamine

foam and the porous aluminum. Valid agreements have been found between the experimen-

tal and numerical data. Future experiments will investigate geometry optimization methods

to increase the absorption curve in frequency bands of interest.

1. Introduction

Sound absorbing materials are widely used in industrial noise control, especially to enhance the acoustic quality of environ-

ments such as cinemas, theaters, concert halls, among others. One of the most frequent problems in engineering noise control

is the development of sound absorbers that provide desirable attenuation with minimal cost or amount of material. Also, inex-

∗Corresponding author.

E-mail address: paulo.mareze@eac.u fsm.br (P.H. Mareze).

https://doi.org/10.1016/j.jsv.2018.11.036

ISO10534_2_Experimental_Transfer_Functions.rar

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December 2018

Paulo Mareze · Eric Brandao · William D'Andrea Fonseca · Olavo M. Silva · Arcanjo Lenzi

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