Investigation on the Sound Absorption Properties of MPA/MR

2009 ◽  
Vol 79-82 ◽  
pp. 2147-2150 ◽  
Author(s):  
Yan Hong Ma ◽  
Jie Hong ◽  
Bin Zhu ◽  
Hong Wang
Keyword(s):  
Sound Absorption ◽  
Sound Propagation ◽  
Propagation Theory ◽  
Wave Tube ◽  
Absorption Properties ◽  
Acoustic Characteristics ◽  
Analogy Method ◽  
Metal Rubber ◽  
Standing Wave Tube ◽  
Application Prospects

This paper introduces a sound absorption structure named as MPA/MR which is a combination of the MPA and Metal Rubber (MR) material. On the basis of Rayleigh model and sound propagation theory in pipe, according to the acoustoelectric analogy method, the theoretical acoustic model of MPA/MR is established, and the formula of absorption coefficient is derived. The multi-function standing wave tube with two microphones was used to obtain acoustic characteristics of MPA/MR experimentally, and the effects of the parameters were analyzed as well. The investigation indicates that MPA/MR can be applied with a broad range of application prospects.

Sound Absorption Properties of Polyester Fibers Needle-Punched Nonwoven Fabrics

2011 ◽  
Vol 332-334 ◽  
pp. 1300-1303
Author(s):  
Ke Tian Guan ◽  
Xu Pin Zhuang ◽  
Xiao Ning Jiao ◽  
Men Qin Li ◽  
Hong Jun Li ◽  
...  
Keyword(s):  
Surface Structure ◽  
Standing Wave ◽  
Sound Absorption ◽  
Fiber Diameter ◽  
Absorption Property ◽  
Wave Tube ◽  
Absorption Properties ◽  
Nonwoven Fabrics ◽  
Polyester Fibers ◽  
Standing Wave Tube

Polyester fiber needle-punched nonwovens with different structures were manufactured and their sound absorption properties were examined using the standing wave tube method. The results show that the sound absorption property of the nonwovens depends on their thickness, needling intensity, fiber diameter and surface structure.

Fabrication and Sound Absorption Properties of Porous Fe0.2(Co20Ni80)0.8 Alloy Microfibers

2012 ◽  
Vol 538-541 ◽  
pp. 2220-2223
Author(s):  
Xiang Qian Shen ◽  
Hong Bo Liu ◽  
Qing Rong Liang ◽  
Xin Chun Yang
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Transformation Process ◽  
Sound Absorption Coefficient ◽  
Wave Tube ◽  
Absorption Properties ◽  
Thick Sample ◽  
Noise Absorption ◽  
Reduction Coefficient ◽  
Standing Wave Tube

The porous nanocrystalline Fe0.2(Co20Ni80)0.8 alloy microfibers with diameters of 2-4 μm have been prepared by the citrate-gel and phase transformation process. The sound absorption coefficient for microfibers samples is measured by the standing wave tube method and it is is over 0.8 for the 15 mm thick sample at the frequency range of 2300-6000 Hz, which is extended to 600-6300 Hz for the 40 mm thick sample. The band width with the sound absorption coefficient above 0.6 is wider than 4300 Hz for the 15 mm thick sample and 5800 Hz for the 40 mm thick sample. For the 40 mm thick sample, the maximum absorption coefficient, noise absorption coefficient, noise reduction coefficient and half-width of the absorption peak are 0.99, 0.59, 0.64 and 5828 Hz, respectively. These microfibers are promising advanced acoustic absorbers.

scholarly journals Effect of Thickness, Density and Cavity Depth on the Sound Absorption Properties of Wool Boards

2018 ◽  
Vol 18 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Hua Qui ◽  
Yang Enhui
Keyword(s):  
Sound Absorption ◽  
Raw Material ◽  
Wave Tube ◽  
Absorption Coefficients ◽  
Absorption Properties ◽  
Cavity Depth ◽  
Low Frequencies ◽  
High Frequencies ◽  
Standing Wave Tube ◽  
Better Than

Abstract A novel wool absorption board was prepared by using a traditional non-woven technique with coarse wools as the main raw material mixed with heat binding fibers. By using the transfer-function method and standing wave tube method, the sound absorption properties of wool boards in a frequency range of 250-6300 Hz were studied by changing the thickness, density, and cavity depth. Results indicated that wool boards exhibited excellent sound absorption properties, which at high frequencies were better than that at low frequencies. With increasing thickness, the sound absorption coefficients of wool boards increased at low frequencies and fluctuated at high frequencies. However, the sound absorption coefficients changed insignificantly and then improved at high frequencies with increasing density. With increasing cavity depth, the sound absorption coefficients of wool boards increased significantly at low frequencies and decreased slightly at high frequencies.

Study of a Sound Absorbing Polyurethane Based on Porous Composite Material

2013 ◽  
Vol 275-277 ◽  
pp. 1623-1627 ◽  
Author(s):  
Xin Liang Zhang ◽  
Cun Ping Liu
Keyword(s):  
Sound Absorption ◽  
Glass Fibers ◽  
Low Frequency ◽  
Wave Tube ◽  
Porous Composite ◽  
Blowing Agent ◽  
Reduction Coefficient ◽  
Absorbing Material ◽  
New Type ◽  
Standing Wave Tube

A new type of sound absorbing material, which was made from super strength polyurethane and mass fiber, was investigated. And the sound absorption coefficient of the material was tested by standing wave tube method. Experiment results manifested that content of glass fibers, blowing agent and thickness have great effects on the sound absorbing performance of the sample. When the content of glass fiber and blowing agent are separately 3% and 0.4%, the performance of the material reaches optimum. The noise reduction coefficient of the material is 0.6, and the sound absorption property at middle-low frequency is good.

scholarly journals Nanofiber-enhanced lightweight composite textiles for acoustic applications

2016 ◽  
Vol 46 (7) ◽  
pp. 1498-1510 ◽  
Author(s):  
Merve Kucukali-Ozturk ◽  
Elif Ozden-Yenigun ◽  
Banu Nergis ◽  
Cevza Candan
Keyword(s):  
Surface Coating ◽  
Sound Absorption ◽  
Sound Propagation ◽  
Absorption Properties ◽  
Knitted Fabrics ◽  
Deposition Amount ◽  
Novel Approach ◽  
Macro Scale ◽  
Additional Processing ◽  
Processing Steps

This paper proposes lightweight textile acoustic structure, wherein electrospun polyacrylonitrile-based nanofibers enhance sound absorption properties with no weight and thickness penalty. Polyacrylonitrile nanofibers with diameter of 110 ± 7 nm were electrospun on spacer-knitted fabrics by varying deposition amount and surface coating arrangement. Proposed novel approach eliminated additional processing steps such as handling and post-lamination and provided easy scalability of nanofibers at macro-scale. The results showed that the sound absorption of nano-enhanced specimens was improved drastically when deposited amount of nanofibers or its effective surface area increased. Sound propagation paths in different configurations were interpreted from sound absorption and air permeability measurements. The sound absorption coefficient values up to 0.7 are achieved in the low and medium frequency ranges with no weight and thickness penalty by tuning deposition amount and surface coating arrangement.

Research on Sound Absorption Properties of Aramid Micro-Perforated Composite Sound Absorbing Material

2010 ◽  
Vol 458 ◽  
pp. 14-22
Author(s):  
Yi Fang Wen ◽  
Yan Nian Rui ◽  
Hong Wei Wang ◽  
Xin Chen
Keyword(s):  
Sound Absorption ◽  
Impact Resistance ◽  
Aramid Fibers ◽  
Absorption Properties ◽  
Mechanical And Electrical Properties ◽  
Acoustic Standing Wave ◽  
Absorbing Material ◽  
Standing Wave Tube ◽  
Materials Used ◽  
Different Thickness

Aramid fiber is one of the most promising materials used in secondary structure of the airplane, which has many merits such as low density, abrasion resistance, impact resistance, permanent flame retardance etc. Current research at home and abroad is mainly on the manufacturing process, mechanical and electrical properties of aramid fibers while the sound absorption property research is less. We prepared aramid micro-perforated composite materials according to the theory of micro-perforated absorber, in order to test and analyse sound absorption properties of micro-perforated sound-absorbing materials with different thickness, aperture, perforation ratio and combined program by using acoustic standing wave tube measurement system. Experimental results show that: the absorption effect of the Micro-perforated Panel Aramid Composite is obvious, in a certain frequency; the absorption coefficient is greatly improved. The study offers a new method for aramid fibers which could be applied in planes and cars.

Development of a Standing Wave-Tube System for Acoustical Property Measurement of Sound Absorption Materials Used on Vehicles

2011 ◽  
Vol 474-476 ◽  
pp. 1146-1150
Author(s):  
Yan Song Wang ◽  
Jian Peng Zhou ◽  
Yan Feng Xing
Keyword(s):  
Standing Wave ◽  
Sound Absorption ◽  
Ratio Method ◽  
Wave Tube ◽  
Tube System ◽  
Signal Amplifier ◽  
Acoustical Property ◽  
Property Measurement ◽  
Standing Wave Tube ◽  
Materials Used

A standing wave-tube system for acoustical property measurement of vehicle-used sound absorption materials is developed in this paper. Theoretically, the standing wave ratio method and the two-cavity method with two-microphone configurations are combined and applied for calculating some acoustical parameters, such as sound absorption ratio, reflection coefficient, characteristic impedance, propagation constant, of a sample material. Based on the combined method, the standing wave-tube system including two microphones, an A/D board, a signal amplifier, a DSP computer and a set of software is carefully designed and performed. The verification results suggest that the newly designed system is accurate for acoustical property measurement of the materials used on vehicles. It can be directly used for selecting noise-control materials in vehicle acoustical designs.

Quantitative study on energy dissipation mechanism of metal rubber by an enhanced turbulence model

2019 ◽  
Vol 33 (33) ◽  
pp. 1950413 ◽  
Author(s):  
Zhuo Zhou ◽  
Jiu Hui Wu ◽  
Xiao Liang ◽  
Mei Lin ◽  
Xiao Yang Yuan
Keyword(s):  
Energy Spectrum ◽  
Energy Dissipation ◽  
Turbulence Model ◽  
Sound Absorption ◽  
Structural Parameters ◽  
Wind Tunnel Test ◽  
Power Laws ◽  
Mathematical Tool ◽  
Metal Rubber ◽  
Standing Wave Tube

This paper studies the energy dissipation of metal rubber with an enhanced turbulence model. Based on the catastrophe theory which is a highly generalized mathematical tool, a new method for studying turbulence is proposed, which can quantitatively analyze the energy dissipation of the whole turbulence developed to process and strictly deduce the expression of the energy spectrum density in different turbulence development stages. Then, a theoretical model of sound absorption performance in full-frequency is established by this enhanced turbulence model. Furthermore, the sound absorption property and energy dissipation of metal rubber are studied under different structural parameters. This paper not only demonstrates −10/9 and −5/3 power laws of the energy spectrum but also finds −3 power laws at high frequencies. Finally, the accuracy of the enhanced turbulence model and the feasibility of the metal rubber research method based on the enhanced turbulence model are verified by wind tunnel test and standing wave tube test, respectively. This study not only has a theoretical guidance for the preparation of metal rubber but also has a new perspective for the study of turbulent phase transition and even other complex phase transitions.

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