Effects of compression on sound absorption of transversely isotropic fibrous materials at oblique incidence

2013 ◽  
Vol 74 (3) ◽  
pp. 383-395 ◽  
Author(s):  
Reza Keshavarz ◽  
Abdolreza Ohadi
Keyword(s):  
Sound Absorption ◽  
Oblique Incidence ◽  
Transversely Isotropic ◽  
Fibrous Materials

Acoustic performance prediction of anechoic layer using identified viscoelastic parameters

2018 ◽  
Vol 25 (6) ◽  
pp. 1164-1178 ◽  
Author(s):  
Meng Tao ◽  
Hanfeng Ye ◽  
Xuefeng Zhao
Keyword(s):  
Performance Prediction ◽  
Sound Absorption ◽  
Oblique Incidence ◽  
Cylindrical Tube ◽  
The Other ◽  
Reflection Coefficients ◽  
Dynamic Parameters ◽  
Acoustic Performance ◽  
Viscoelastic Parameters ◽  
Cylindrical Holes

In this work, the acoustic performance of an anechoic layer, which contains horizontally-distributed cylindrical holes, has been studied using identified viscoelastic dynamic parameters. First, the reflection coefficients of two different viscoelastic anechoic layers (one solid and the other perforated), tested in a water-filled pipe, have been used to develop the identification method for viscoelastic dynamic parameters. In the proposed method, the complex longitudinal wavenumber and the complex transverse wavenumber can be obtained by solving the characteristic equation of viscoelastic cylindrical tube. Then, simulations have been performed using COMSOL software to predict the acoustic performance of the anechoic layer. Based on the model and the identified viscoelastic parameters, the effects of different structural properties, including the radius of hole, the hole horizontal spacing, and the arrangements of holes, on the sound absorption of anechoic layer have been analyzed and discussed. Particularly, the acoustic performance of an anechoic layer under oblique incidence has also been considered.

Investigation on sound absorption properties for recycled fibrous materials

2012 ◽  
Vol 43 (1) ◽  
pp. 56-73 ◽  
Author(s):  
Hoda Soliman Seddeq ◽  
Nermin M Aly ◽  
Ali Marwa A ◽  
MH Elshakankery
Keyword(s):  
Sound Absorption ◽  
Fibrous Materials ◽  
Absorption Properties

Effects of compression on the sound absorption of fibrous materials

2000 ◽  
Vol 61 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Bernard Castagnède ◽  
Achour Aknine ◽  
Bruno Brouard ◽  
Viggo Tarnow
Keyword(s):  
Sound Absorption ◽  
Fibrous Materials

scholarly journals A Pilot Study on the Sound Absorption Characteristics of Chicken Feathers as an Alternative Sustainable Acoustical Material

2019 ◽  
Vol 11 (5) ◽  
pp. 1476 ◽  
Author(s):  
Asniawaty Kusno ◽  
Kimihiro Sakagami ◽  
Takeshi Okuzono ◽  
Masahiro Toyoda ◽  
Toru Otsuru ◽  
...  
Keyword(s):  
Pilot Study ◽  
Sound Absorption ◽  
Prediction Method ◽  
Fibrous Materials ◽  
Absorption Coefficients ◽  
Chicken Feathers ◽  
Absorption Performance ◽  
Flow Resistivity ◽  
Impedance Tube Method ◽  
Absorption Characteristics

This communication reports the results of a pilot study on the sound absorption characteristics of chicken feathers (CFs). Recently, demands for natural and sustainable materials have been extensively studied for acoustical purposes. CF has long been left wasted, however, they can be used for sound-absorbing purposes to improve acoustical environments as a sustainable and green acoustical material. In order to clarify their feasibility, samples of CF absorbers of various densities and thicknesses were prepared, and their sound absorption coefficients were measured by the standard impedance tube method. The measured results were also compared with those of conventional glass wools of the same densities and thicknesses. The results show that CFs have potentially good sound-absorption performance, which is similar to typical fibrous materials: increasing with frequency. Results of direct comparison with glass wool demonstrate that the absorption coefficients of CFs are comparable and, at some frequencies, somewhat higher than conventional glass wools in some cases. Additionally, the first step for searching a prediction method for the sound absorption performance of CFs, their flow resistivity was measured and a Delany–Bazley–Miki model was examined. However, the resultant flow resistivity was unexpectedly low, and the model gave only a much lower value than that measured. The reason for the discrepancies is the subject of a future study.

scholarly journals Additional Sound Absorption Within a Poroelastic Lamella Network Under Oblique Incidence

2018 ◽  
Vol 104 (2) ◽  
pp. 211-219 ◽  
Author(s):  
Nicolas Dauchez ◽  
Benoit Nennig ◽  
Olivier Robin
Keyword(s):  
Sound Absorption ◽  
Oblique Incidence

Airflow resistance of acoustical fibrous materials: Measurements, calculations and applications

2018 ◽  
Vol 49 (8) ◽  
pp. 981-1010 ◽  
Author(s):  
Xiaoning Tang ◽  
Xiong Yan
Keyword(s):  
Sound Absorption ◽  
Normal Incidence ◽  
Industrial Applications ◽  
Current Status ◽  
Fibrous Materials ◽  
Characteristic Parameters ◽  
Airflow Resistance ◽  
Reverberation Chamber ◽  
Acoustic Performance ◽  
Crucial Parameter

The acoustic performance of fibrous materials is mainly determined by its airflow resistance, and it is a parameter of the resistance that the airflow meets through the materials. This paper has summarized the recent advances on the measurements, calculations and applications of airflow resistance. Firstly, different methods for airflow resistance measurements are presented, mainly including the direct airflow method, alternating airflow method and acoustical method. We have summarized the development history, current status and industrial applications of these methods. Secondly, this paper has summarized the models of calculating airflow resistance. Most of these empirical models are based on the characteristic parameters of fibrous materials, for instance bulk density, fiber diameter, porosity and thickness. Thirdly, this review has gathered the applications of airflow resistance in sound absorption and noise control. It is a crucial parameter in the prediction of both normal incidence sound absorption and reverberation chamber sound absorption. In conclusion, this review has concluded with some perspectives for the measurements, calculations and applications of airflow resistance.

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