The Structural Design of Combined Absorber Composed by MPP and Multi-Layer Porous Material Based on VA One

2012 ◽  
Vol 571 ◽  
pp. 91-96
Author(s):  
Xiu Hua Duan ◽  
Huan Qin Wang ◽  
Wen Juan Sun ◽  
De Yi Kong ◽  
Zhan Zhao
Keyword(s):  
Optimal Design ◽  
Porous Material ◽  
Porous Materials ◽  
Porous Layer ◽  
Structural Design ◽  
Sound Absorption ◽  
New Method ◽  
Optimum Location ◽  
Absorption Performance

Some experiments found that the low-frequncy sound absorption performance can be improved by inserting MPP into the multi-layer porous materials, but the theory modeling of this MPP-multi-layer porous combined absorber is too difficult to provide the guidance. Therefore, a new method is proposed in this paper, according to Atalla’s theory, the MPP can be treated as a rigid porous layer in this composite absorber, then the acoustic software (such as VA One) usually for dealing with multi-layer porous absorber can be chosen to its optimal design. Based on this method, a two-layer porous absorber is designed using the Foam Module of VA One, and the influence of different insert location of MPP in the two-layer porous absorber is analyzed, which shows the existence of optimum location. Moreover, the sound absorption of different MPP structure at the optimum location is also discussed which shows inserting the wider-band MPP structure is better.

scholarly journals Diffuse Sound Absorptive Properties of Parallel-Arranged Perforated Plates with Extended Tubes and Porous Materials

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1091 ◽  
Author(s):  
Dengke Li ◽  
Daoqing Chang ◽  
Bilong Liu
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Porous Materials ◽  
Sound Absorption ◽  
Azimuthal Angle ◽  
Octave Band ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Perforated Plates ◽  
Absorption Performance

The diffuse sound absorption was investigated theoretically and experimentally for a periodically arranged sound absorber composed of perforated plates with extended tubes (PPETs) and porous materials. The calculation formulae related to the boundary condition are derived for the periodic absorbers, and then the equations are solved numerically. The influences of the incidence and azimuthal angle, and the period of absorber arrangement are investigated on the sound absorption. The sound-absorption coefficients are tested in a standard reverberation room for a periodic absorber composed of units of three parallel-arranged PPETs and porous material. The measured 1/3-octave band sound-absorption coefficients agree well with the theoretical prediction. Both theoretical and measured results suggest that the periodic PPET absorbers have good sound-absorption performance in the low- to mid-frequency range in diffuse field.

Sound absorption of a finite flexible micro-perforated panel absorber back by a rigid air cavity filled with a fibrous porous material

2021 ◽  
Vol 263 (3) ◽  
pp. 3625-3632
Author(s):  
Ho Yong Kim ◽  
Yeon June Kang
Keyword(s):  
Energy Dissipation ◽  
Porous Material ◽  
Fibrous Material ◽  
Alternative Energy ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Absorption Coefficients ◽  
Air Cavity ◽  
Acoustic Cavity ◽  
Absorption Performance

Back by a rigid cavity filled with a layer of porous layer, the sound absorption performance of a micro-perforated panel (MPP) can be enhanced in comparison with other resonance based sound absorbers. In this paper, a theoretical model of a finite flexible MPP back by a rigid air cavity filled with a fibrous porous material is developed to predict normal sound absorption coefficients. Displacements of MPP and sound pressure field in fibrous porous material and acoustic cavity are expressed using a series of modal functions, and the sound absorption coefficients of MPP system are obtained. Additionally, comparison of energy dissipation by MPP and fibrous material is performed to identify effects of a fibrous material on the sound absorption of a MPP. As expected, at anti-resonance frequency of an MPP, the fibrous material provide an alternative energy dissipation mechanism.

scholarly journals On-demand optimize design of sound-absorbing porous material based on multi-population genetic algorithm

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 122-132
Author(s):  
Yonghua Wang ◽  
Shengfu Liu ◽  
Haiquan Wu ◽  
Chengchun Zhang ◽  
Jinkai Xu ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Porous Material ◽  
High Frequency ◽  
Population Genetic ◽  
Sound Absorption ◽  
Perforated Plate ◽  
Noise Spectrum ◽  
Absorption Effect ◽  
Absorption Performance ◽  
Population Genetic Algorithm

AbstractPorous material (PM) shows good sound absorption performance, however, the sound absorbing property of PM with different parameters are greatly different. In order to match the most suitable absorbing materials with the most satisfactory sound-absorbing performance according to the noise spectrum in different practical applications, multi-population genetic algorithm is used in this paper to optimize the parameters of porous sound absorbing structures that are commonly used according to the actual demand of noise reduction and experimental verification. The results shows that the optimization results of multi-population genetic algorithm are obviously better than the standard genetic algorithm in terms of sound absorption performance and sound absorption bandwidth. The average acoustic absorption coefficient of PM can reach above 0.6 in the range of medium frequency, and over 0.8 in the range of high frequency through optimization design. At a mid-to-high frequency environment, the PM has a better sound absorption effect and a wider frequency band than that of micro-perforated plate. However, it has a poor sound absorption effect at low frequency. So it is necessary to select suitable sound absorption material according to the actual noise spectrum.

Hybrid Active and Passive Noise Control of Cavities

2011 ◽  
Vol 97 (5) ◽  
pp. 752-760 ◽  
Author(s):  
Lenin Babu ◽  
Chandramouli Padmanabhan
Keyword(s):  
Porous Material ◽  
Elastic Material ◽  
Sound Absorption ◽  
Noise Suppression ◽  
Noise Control ◽  
Active Noise Control ◽  
Elastic Materials ◽  
Active Noise ◽  
Absorption Performance ◽  
Passive Noise

In this paper a hybrid active noise control of a cavity with poro-elastic material has been investigated. It has been found that the noise reduction achieved with active noise control in the cavity without poro-elastic material is not significantly altered with the presence of poro-elastic materials. This is shown to be independent of the porous material and its thickness and is true both at lower and mid-frequency ranges. Further, it is seen that macro perforations do not alter the sound absorption performance of the poro-elastic material in the presence of active noise control. The results clearly indicate that one can choose a smaller thickness of the porous material when active noise control is used in a cavity for noise suppression.

scholarly journals Structural Design and Sound Absorption Properties of Nitrile Butadiene Rubber-Polyurethane Foam Composites with Stratified Structure

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 946 ◽  
Author(s):  
Xueliang Jiang ◽  
Zhijie Wang ◽  
Zhen Yang ◽  
Fuqing Zhang ◽  
Feng You ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Structural Design ◽  
Sandwich Structure ◽  
Sound Absorption ◽  
Low Frequency ◽  
Thickness Ratio ◽  
Butadiene Rubber ◽  
Absorption Mechanism ◽  
Nitrile Butadiene Rubber ◽  
Absorption Performance

Sound absorbing composites with stratified structures, including double-layer and sandwich structures, were prepared through the combination of nitrile butadiene rubber (NBR) and polyurethane foam (PUFM). The effects of the thickness ratio of layers, different stratified structures and the variety of fillers on the sound absorption performance of the NBR-PUFM composites and the sound absorption mechanism were studied. The results show that the NBR-PUFM composite with a sandwich structure and thickness ratio of 1:8:1 displays good sound absorption, which could be improved further by adding fillers. Because the airflow resistivity, resonance absorption, interface dissipation and interface reflection were combined organically in the sandwich structure, the composites show excellent low-frequency sound absorption performance. Moreover, the composite also has advantages in cost and functionalization aspects.

Experimental and computational investigation of sound absorption performance of sustainable porous material: Yucca Gloriosa fiber

2020 ◽  
Vol 157 ◽  
pp. 106999 ◽  
Author(s):  
Parham Soltani ◽  
Ebrahim Taban ◽  
Mohammad Faridan ◽  
Seyed Ehsan Samaei ◽  
Somayeh Amininasab
Keyword(s):  
Porous Material ◽  
Sound Absorption ◽  
Computational Investigation ◽  
Absorption Performance

Acoustic performance of countersunk micro-perforated panel in multilayer porous material

2019 ◽  
Vol 27 (1) ◽  
pp. 3-20 ◽  
Author(s):  
L Yuvaraj ◽  
S Jeyanthi
Keyword(s):  
Additive Manufacturing ◽  
Porous Material ◽  
Porous Materials ◽  
Transfer Matrix Method ◽  
Sound Absorption ◽  
Integration Method ◽  
Absorption Bandwidth ◽  
Acoustic Performance ◽  
Hole Profile ◽  
Materials Used

This study investigates the acoustic performance of a countersunk micro-perforated panel, along with two distinct porous materials used in a multilayer porous absorber configuration. Additive manufacturing is applied to create sub-millimeter perforation with different hole spacings on polymer micro-perforated panels. Experiments are conducted in an impedance tube, in which the effects of the perforation ratio, air gap, and varying porous layer configurations on the sound absorption capabilities are investigated. For validation, considering the converging hole profile in the micro-perforated panel, an integration method with end correction is used to calculate the tapered section impedance, and the traditional Maa theory is used for the uniform hole. The theoretical impedance of the multilayer absorber is calculated using the transfer matrix method and subsequently compared to the experimental results. The results demonstrate that the countersunk hole micro-perforated panel exhibits a significant improvement in sound absorption, and the introduction of porous materials extends the sound absorption bandwidth. Furthermore, the results indicate that the sound absorption capability depends on the porous material placement in the multilayer absorber configuration.

scholarly journals Enhanced Low-Frequency Sound Absorption of a Porous Layer Mosaicked with Perforated Resonator

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 223
Author(s):  
Xin Li ◽  
Bilong Liu ◽  
Qianqian Wu
Keyword(s):  
Porous Material ◽  
Absorption Coefficient ◽  
Porous Layer ◽  
Acoustic Impedance ◽  
Sound Absorption ◽  
Perforated Plate ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Frequency Sound ◽  
Two Samples

A composite structure composed of a porous-material layer mosaicked with a perforated resonator is proposed to improve the low-frequency sound absorption of the porous layer. This structure is investigated in the form of a porous-material matrix (PM) and a perforated resonator (PR), and the PR is a thin perforated plate filled with porous material in its back cavity. Theoretical and numerical models are established to predict the acoustic impedance and sound absorption coefficient of the proposed structure, and two samples made of polyurethane and melamine, respectively, are tested in an impedance tube. The predicted results are consistent with that of the measured. Compared with a single porous layer with the same thickness, the results show that the designed structure provides an additional sound absorption peak at low frequencies. The proposed structure is compact and has an effective absorption bandwidth of more than two octaves especially below the frequency corresponding to 1/4 wavelength. A comparison is also made between the sound absorption coefficients of the proposed structure and a classical micro-perforated plate (MPP), and the results reveal equivalent acoustic performance, suggesting that it can be used as an alternative to the MPP for low–mid frequency sound absorption. Moreover, the influences of the main parameters on the sound absorption coefficient of PPCS are also analyzed, such as the hole diameter, area ratio, flow resistance, and porous-material thickness in the PR. The mechanism of sound absorption is discussed through the surface acoustic impedance and the distributions of particle velocity and sound pressure at several specific frequencies. This work provides a new idea for the applications of the thin porous layer in low- and medium-frequency sound absorption.

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