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.

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 Optimization and Validation of Sound Absorption Performance of 10-Layer Gradient Compressed Porous Metal

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 588 ◽  
Author(s):  
Fei Yang ◽  
Xinmin Shen ◽  
Panfeng Bai ◽  
Xiaonan Zhang ◽  
Zhizhong Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Sound Absorption ◽  
Search Algorithm ◽  
Theoretical Data ◽  
Porous Metal ◽  
Cuckoo Search ◽  
Absorption Coefficients ◽  
Element Simulation ◽  
Absorption Performance

Sound absorption performance of a porous metal can be improved by compression and optimal permutation, which is favorable to promote its application in noise reduction. The 10-layer gradient compressed porous metal was proposed to obtain optimal sound absorption performance. A theoretical model of the sound absorption coefficient of the multilayer gradient compressed porous metal was constructed according to the Johnson-Champoux-Allard model. Optimal parameters for the best sound absorption performance of the 10-layer gradient compressed porous metal were achieved by a cuckoo search algorithm with the varied constraint conditions. Preliminary verification of the optimal sound absorber was conducted by the finite element simulation, and further experimental validation was obtained through the standing wave tube measurement. Consistencies among the theoretical data, the simulation data, and the experimental data proved accuracies of the theoretical sound absorption model, the cuckoo search optimization algorithm, and the finite element simulation method. For the investigated frequency ranges of 100–1000 Hz, 100–2000 Hz, 100–4000 Hz, and 100–6000 Hz, actual average sound absorption coefficients of optimal 10-layer gradient compressed porous metal were 0.3325, 0.5412, 0.7461, and 0.7617, respectively, which exhibited the larger sound absorption coefficients relative to those of the original porous metals and uniform 10-layer compressed porous metal with the same thickness of 20 mm.

scholarly journals Improving and Optimizing Sound Absorption Performance of Polyurethane Foam by Prepositive Microperforated Polymethyl Methacrylate Panel

2020 ◽  
Vol 10 (6) ◽  
pp. 2103
Author(s):  
Xiaocui Yang ◽  
Xinmin Shen ◽  
Haiqin Duan ◽  
Fei Yang ◽  
Xiaonan Zhang ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Composite Structures ◽  
Sound Absorption ◽  
Search Algorithm ◽  
Cuckoo Search ◽  
Cuckoo Search Algorithm ◽  
Absorption Model ◽  
Absorption Coefficients ◽  
Element Simulation ◽  
Absorption Performance

Sound absorption performance of polyurethane foam could be improved by adding a prepositive microperforated polymethyl methacrylate panel to form a composite sound-absorbing structure. A theoretical sound absorption model of polyurethane foam and that of the composite structure were constructed by the transfer matrix method based on the Johnson–Champoux–Allard model and Maa’s theory. Acoustic parameter identification of the polyurethane foam and structural parameter optimization of the composite structures were obtained by the cuckoo search algorithm. The identified porosity and static flow resistivity were 0.958 and 13078 Pa·s/m2 respectively, and their accuracies were proved by the experimental validation. Sound absorption characteristics of the composite structures were verified by finite element simulation in virtual acoustic laboratory and validated through standing wave tube measurement in AWA6128A detector. Consistencies among the theoretical data, simulation data, and experimental data of sound absorption coefficients of the composite structures proved the effectiveness of the theoretical sound absorption model, cuckoo search algorithm, and finite element simulation method. Comparisons of actual average sound absorption coefficients of the optimal composite structure with those of the original polyurethane foam proved the practicability of this identification and optimization method, which was propitious to promote its practical application in noise reduction.

scholarly journals High-Temperature and Low-Frequency Acoustic Energy Absorption by a Novel Porous Metamaterial Structure

2021 ◽  
Author(s):  
Qihang Liu ◽  
Xuewei Liu ◽  
Chuanzeng Zhang ◽  
Fengxian Xin
Keyword(s):  
High Temperature ◽  
Theoretical Model ◽  
Porous Material ◽  
Energy Absorption ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Frequency Range ◽  
Metamaterial Structure ◽  
Equivalent Inclusion ◽  
Absorption Performance

AbstractIn this paper, we propose a novel porous metamaterial structure with an improved acoustic energy absorption performance at high-temperature and in the low-frequency range. In the proposed novel porous metamaterial structure, a porous material matrix containing periodically perforated cylindrical holes arranged in a triangular lattice pattern is applied, and additional interlayers of another porous material are introduced around these perforations. The theoretical model is established by adopting the double porosity theory for the interlayer and the cylindrical hole which form an equivalent inclusion and then applying the homogenization method to the porous metamaterial structure formed by the equivalent inclusion and the porous matrix. The temperature-dependent air and material parameters are considered in the extended theoretical model, which is validated by the finite element results obtained by COMSOL Multiphysics. The acoustic or sound energy absorption performance can be improved remarkably at very low frequencies and high temperature. Furthermore, the underlying acoustic energy absorption mechanism inside the unit-cell is investigated by analyzing the distribution of the time-averaged acoustic power dissipation density and the energy dissipation ratio of each constituent porous material. The results reveal that regardless of the temperature, the acoustic energy is mostly dissipated in the porous material with a lower airflow resistivity, while the acoustic energy dissipated in the porous material with a higher airflow resistivity also becomes considerable in the high-frequency range. The novel porous metamaterial structure proposed in this paper can be efficiently utilized to improve the acoustic energy absorption performance at high temperature.

Prediction of random incidence sound absorption coefficients of porous materials

2022 ◽  
Vol 189 ◽  
pp. 108625
Author(s):  
Yujun Zhao ◽  
Jinhui Xu ◽  
John Laurence Davy ◽  
Zhengqing Liu ◽  
Mohammad Fard
Keyword(s):  
Porous Materials ◽  
Sound Absorption ◽  
Absorption Coefficients

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.

Sign in / Sign up

Export Citation Format

Share Document