Investigation of Acoustic Properties on Wideband Sound-Absorber Composed of Hollow Perforated Spherical Structure with Extended Tubes and Porous Materials

Li, Dengke; Jiang, Zhongcheng; Li, Lin; Liu, Xiaobo; Wang, Xianfeng; He, Mingfeng

doi:10.3390/app10248978

Cited by 10 publications

(6 citation statements)

References 22 publications

(29 reference statements)

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“…According to relevant research from Li et al, charcoal has a smaller sound absorption coefficient compared to other commonly used sound-absorbing materials such as melamine foam; this means that it has high reflective properties [40]. Such high reflective properties can be used for the creation of acoustic diffusers containing charcoal elements.…”

Section: Influence Of Charcoal Thickness On Sound Reflection Coefficientmentioning

confidence: 99%

Investigation of Acoustic Efficiency of Wood Charcoal in Impedance Tube for Usage in Sound-Reflective Devices

Khrystoslavenko

Grubliauskas

2022

Sustainability

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Charcoal is an environmentally friendly, biodegradable, and economical material. This material is usually produced by slow pyrolysis—the heating of wood or other substances in the absence of oxygen. The aim of this study was to investigate the acoustic efficiency of charcoal and design an acoustic diffuser that utilizes charcoal. Samples of different types of tree charcoal—birch (Betula pendula), pine (Pinus sylvestris), and oak (Quercus robur)—with different thicknesses were used for the acoustic efficiency measurements. The sound absorption and sound reflection properties of charcoal were investigated. The bulk density of charcoal was measured. In this study, an impedance tube with two microphones was employed as the measurement method. The results of the impedance tube measurements showed that the charcoal samples had high sound reflection coefficients, the highest value of which was 1. The 50 mm samples of birch had a high bulk density of 473 kg/m3. The sample of 50 mm thick oak had the best reflection coefficient at 0.99. Reflection depended on the surface’s acoustic properties, and the sound reflection coefficient increased with the increase in the density. Charcoal measurements, due to the high reflection coefficient of the material, were used for the design of a sound diffuser, which included wooden perforated plates filled with cylindrical elements of wood charcoal.

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Section: Influence Of Charcoal Thickness On Sound Reflection Coefficientmentioning

confidence: 99%

Investigation of Acoustic Efficiency of Wood Charcoal in Impedance Tube for Usage in Sound-Reflective Devices

Khrystoslavenko

Grubliauskas

2022

Sustainability

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“…The porous material placed in front of the MPP helps to absorb high-frequency sound waves, and a large thickness is required for absorbing low-frequency sound waves. Parallel devices with porous materials [14][15][16][17] have also been studied to achieve effective sound absorption at low-mid frequencies in a limited space. A parallel arrangement of three perforated plates with extended tubes (PPETs) and porous materials was used to improve the sound absorption in the frequency range of 100-1600 Hz with a limited total thickness of 100 mm [14].…”

Section: Introductionmentioning

confidence: 99%

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

Liu

2022

Polymers

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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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“…Using the two commonly used optimization methods as examples, the literature on optimization by parametric scanning examines these two techniques. Li et al [4] have developed a new light and thin sound absorption structure that is composed of melamine foam and hollow porous spheres, which significantly enhances the low-frequency sound absorption performance. Jimenez et al [5] have investigated the impact of the incident angle on locally-reactive acoustic metamaterials and the relationship between the ideal absorption peak, the incident angle, and the frequency.…”

Section: Introductionmentioning

confidence: 99%

A Many-Objective Joint Parallel Simulation Method for Acoustic Optimization Design of Sound-Absorbing Structures

2022

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This paper establishes a many-objective MATLAB with a COMSOL joint parallel simulation optimization method in order to solve the current situation of low efficiency, single objective, and poor effect in acoustic optimization design research for a sound-absorbing structure. Our proposed method combines the means for population partitioning, monitoring, and adaptive normalization, within the framework of the NSGA-III algorithm, which takes the hyperplane deployment scheme into account in its entirety. Compared to the traditional genetic algorithm toolbox of the joint COMSOL optimization scheme, it is shown that the joint parallel simulation optimization method that is constructed in this paper achieves a higher optimization efficiency and a better experimental performance, thereby aiding in the identification of the optimal solution to multiple objectives. The optimization efficiency can increase linearly as the number of available cores on the computer increases. This method is then used to construct a parallel, low-frequency, broadband, highly-sound-absorbing structure. Without any constraints on the optimization objective, the diversity of the optimization results is evident within the parameter optimization range of this paper. The optimization results are stable and substantial, with constrained optimization objectives that have some reference value. In addition, the proposed method can solve acoustic vibration optimization problems and can be applied to other finite element optimization problems.

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Investigation of Acoustic Properties on Wideband Sound-Absorber Composed of Hollow Perforated Spherical Structure with Extended Tubes and Porous Materials

Cited by 10 publications

References 22 publications

Investigation of Acoustic Efficiency of Wood Charcoal in Impedance Tube for Usage in Sound-Reflective Devices

Investigation of Acoustic Efficiency of Wood Charcoal in Impedance Tube for Usage in Sound-Reflective Devices

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

A Many-Objective Joint Parallel Simulation Method for Acoustic Optimization Design of Sound-Absorbing Structures

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