Investigation of a Compound Perforated Panel Absorber With Backing Cavities Partially Filled With Polymer Materials

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
C. Q. Wang ◽  
Y. S. Choy
Keyword(s):  
Sound Absorption ◽  
Normal Incidence ◽  
Polyester Fiber ◽  
Polymer Materials ◽  
Element Simulation ◽  
Parallel Arrangement ◽  
Cavity Configuration ◽  
Absorption Performance ◽  
Good Agreement ◽  
Panel Absorber

The paper concerns the sound absorption performance of a compound absorber which consists of a parallel arrangement of multiple perforated panel absorbers of different backing cavity depths partially filled with poroelastic polymer materials. Three polymer materials are considered: expandable polystyrene (EPS) foam, polymethacrylimide (PMI) foam, and polyester fiber. The normal incidence sound absorption coefficients of the compound panel absorber are tested experimentally. Results show that the former two foams can achieve similar absorption performance to the rigid cavity configuration, while the resonances shift to lower frequencies due to the changes of effective cavity depths. It is also found that the additional attenuation by polymer foams may improve sound absorption, but the effect is marginal. For polyester fiber, results show that it performs more like a single perforated panel absorber. Finite element simulation of the compound panel absorber is also discussed, and good agreement is observed between simulated and experimental results.

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 Effect of the Pore Shape and Size of 3D-Printed Open-Porous ABS Materials on Sound Absorption Performance

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4474
Author(s):  
Katarina Monkova ◽  
Martin Vasina ◽  
Peter Pavol Monka ◽  
Drazan Kozak ◽  
Jan Vanca
Keyword(s):  
Sound Absorption ◽  
Negative Impact ◽  
Excitation Frequency ◽  
Volume Ratio ◽  
Acrylonitrile Butadiene Styrene ◽  
Normal Incidence ◽  
Absorption Properties ◽  
Absorption Performance ◽  
3D Printed ◽  
Material Volume

Noise has a negative impact on our environment and human health. For this reason, it is necessary to eliminate excessive noise levels. This paper is focused on the study of the sound absorption properties of materials with open-porous structures, which were made of acrylonitrile butadiene styrene (ABS) material using additive technology. Four types of structures (Cartesian, Octagonal, Rhomboid, and Starlit) were evaluated in this work, and every structure was prepared in three different volume ratios of the porosity and three different thicknesses. The sound absorption properties of the investigated ABS specimens were examined utilizing the normal incidence sound absorption and noise reduction coefficients, which were experimentally determined by the transfer function method using a two-microphone acoustic impedance tube. This work deals with various factors that influence the sound absorption performance of four different types of investigated ABS material’s structures. It was found, in this study, that the sound absorption performance of the investigated ABS specimens is strongly affected by different factors, specifically by the structure geometry, material volume ratio, excitation frequency of an acoustic wave, material’s thickness, and air space size behind the tested sound-absorbing materials.

The Design and Optimization of Nonwoven Composite Boards on Sound Absorption Performance

2013 ◽  
Vol 365-366 ◽  
pp. 1217-1220 ◽  
Author(s):  
Chen Hung Huang ◽  
Yu Chun Chuang
Keyword(s):  
Sound Absorption ◽  
Nonwoven Fabric ◽  
Polyester Fiber ◽  
Design Parameters ◽  
Composite Board ◽  
Design And Optimization ◽  
Nonwoven Fabrics ◽  
Needle Punching ◽  
Optimal Value ◽  
Absorption Performance

This study aims to investigate the optimal value of design parameters for the sound-absorbing nonwoven composite board. The number of laminated layers and thickness of polyester fiber are viewed as the design parameters for fabricating the nonwoven composite board. The 2D, 7D and 12D polyester fibers are individually mixed with 4D low-melting point polyester fiber to produce 2D polyester nonwoven fabric (2D-PETF), 7D polyester nonwoven fabric (7D-PETF) and 12D polyester nonwoven fabric (12D-PETF) respectively. The developed nonwoven fabrics are then used to fabricate 2D-PET, 7D-PET and 12D-PET nonwoven composite boards through the multiple needle-punching and thermal bonding techniques. The sound absorption performance of each PET composite board is carefully examined. The experimental results reveal that the 7D-PET composite board with 10 laminated layers has the optimal sound absorption performance.

scholarly journals Sound Absorption Measurements of Bio-Sourced Esparto-Fibres : Effect of the Compression

2020 ◽  
Vol 9 (2) ◽  
pp. 1827-1832
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Normal Incidence ◽  
Density Variation ◽  
Thickness Variation ◽  
Fibrous Materials ◽  
Low Frequencies ◽  
Conference Room ◽  
Innovative Solution ◽  
Absorption Performance

The use of absorbent materials such as fibrous materials is considered as an innovative solution to solve noise problems. The purpose of this research paper is to study the acoustic absorption of a new bio-sourced fibrous material called "Alfa fibers", in order to use it as an absorbent material to reduce reverberation time in the building construction domain (theatre, cinema, conference room, ...). For that, a set of 36 samples was designed and prepared for different thicknesses and different densities in order to evaluate the effect of thickness variation and density variation on sound absorption performance. An experimental study was carried out to measure the sound absorption coefficient at normal incidence, using the ISO 10534-2 standard method known as two-microphone transfer function method. All tests were performed in a Kundt tube with a diameter of 10 cm, in the frequency range (50-1600 Hz). These measurements show that the absorption coefficient can reach a value of 0.9 around 1000 Hz. The experimental results clearly show that sound absorption improves when the thickness of the samples increases, or when the density increases to an optimal value of 300Kg/m3 from which absorption performance begins to decrease. At low frequencies, sound absorption can be improved by creating an air gap between the sample and the rigid bottom.

scholarly journals Sound-Absorption Properties of Materials Made of Esparto Grass Fibers

2020 ◽  
Vol 12 (14) ◽  
pp. 5533 ◽  
Author(s):  
Jorge P. Arenas ◽  
Romina del Rey ◽  
Jesús Alba ◽  
Roberto Oltra
Keyword(s):  
Sound Absorption ◽  
Natural Fibers ◽  
Normal Incidence ◽  
Absorbing Materials ◽  
Absorbing Material ◽  
Absorption Performance ◽  
Sustainable Materials ◽  
Reasonable Prediction ◽  
Best Fit

Research on sound-absorbing materials made of natural fibers is an emerging area in sustainable materials. In this communication, the use of raw esparto grass as an environmentally friendly sound-absorbing material is explored. Measurements of the normal-incidence sound-absorption coefficient and airflow resistivity of three different types of esparto from different countries are presented. In addition, the best-fit coefficients for reasonable prediction of the sound-absorption performance by means of simple empirical formulae are reported. These formulae require only knowledge of the airflow resistivity of the fibrous material. The results presented in this paper are an addition to the characterization of available natural fibers to be used as alternatives to synthetic ones in the manufacturing of sound-absorbing materials.

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