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.

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 Low Frequency Sound Absorption by Optimal Combination Structure of Porous Metal and Microperforated Panel

2019 ◽  
Vol 9 (7) ◽  
pp. 1507 ◽  
Author(s):  
Xinmin Shen ◽  
Panfeng Bai ◽  
Xiaocui Yang ◽  
Xiaonan Zhang ◽  
Sandy To
Keyword(s):  
Finite Element ◽  
Sound Absorption ◽  
Search Algorithm ◽  
Low Frequency ◽  
Porous Metal ◽  
Cuckoo Search ◽  
Element Model ◽  
Frequency Sound ◽  
Sound Absorber ◽  
Standing Wave Tube

The combination structure of a porous metal and microperforated panel was optimized to develop a low frequency sound absorber. Theoretical models were constructed by the transfer matrix method based on the Johnson—Champoux—Allard model and Maa’s theory. Parameter optimizations of the sound absorbers were conducted by Cuckoo search algorithm. The sound absorption coefficients of the combination structures were verified by finite element simulation and validated by standing wave tube measurement. The experimental data was consistent with the theoretical and simulation data, which proved the efficiency, reliability, and accuracy of the constructed theoretical sound absorption model and finite element model. The actual average sound absorption coefficient of the microperforated panel + cavity + porous metal + cavity sound absorber in the 100–1800 Hz range reached 62.9615% and 73.5923%, respectively, when the limited total thickness was 30 mm and 50 mm. The excellent low frequency sound absorbers obtained can be used in the fields of acoustic environmental protection and industrial noise reduction.

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.

Design of Transformer Substation Low Frequency Sound Absorber and Test Study on Sound Absorption Property

2013 ◽  
Vol 468 ◽  
pp. 134-140 ◽  
Author(s):  
Xia Zhang ◽  
Shu Ning Duan ◽  
Mei Gen Cao ◽  
Juan Mo ◽  
Yu Han Sun ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Frequency Sound ◽  
Sound Absorber ◽  
Test Study ◽  
Transformer Substation ◽  
Cavity Thickness ◽  
Standing Wave Tube

In allusion to the characteristic that transformer noise is mainly low-frequency noise, firstly the sound absorber is studied and analyzed on aspect of materials, sound absorption structure cavity thickness and punching rate etc in standing wave tube laboratory, secondly transformer substation low-frequency sound absorber is presented, and finally sound absorption properties of absorber is verified through random incidence Test. The analyses and study indicates that: compared with thin plate resonance absorber and micropunching sound absorber, the sound absorption band width of transformer substation low-frequency sound absorber has been improved under unchanged sound absorption effect and transformer low-frequency noise may be effectively absorbed.

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.

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.

Experimental Study on Sound Absorption Property of Porous Concrete Pavement Layer

2014 ◽  
Vol 507 ◽  
pp. 238-241 ◽  
Author(s):  
Tong Yuan Ni ◽  
Chen Hui Jiang ◽  
Hui Xing Tai ◽  
Guo Qing Zhao
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Absorption Capacity ◽  
Concrete Pavement ◽  
Absorption Property ◽  
Porous Concrete ◽  
Acoustic Performance ◽  
Standing Wave Tube ◽  
Pavement Thickness

In this paper, Sound absorption property tests of porous concrete pavement specimens which porosity of 15%, respectively, 17%, 20%, 22%,25% and a thickness of 40mm, 50mm, 60mm have been done by standing wave tube in different frequencies. The experimental results showed that the different porosity specimens sound absorption capacity shows little difference in low-frequency sound. As the porosity of porous concrete pavement layer specimen increases, the absorption coefficient increases. Under the same porosity as the porous concrete pavement thickness increases, the sound absorption coefficient in low-frequency tends to increase, and in high-frequency, it tends to decrease. The mix design of porous concrete pavement should be considered about permeability, strength, acoustic performance and other factors. The paper recommends porous concrete pavement porosity ranges 17-22%.

scholarly journals Array MEMS Vector Hydrophone Oriented at Different Direction Angles

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4282 ◽  
Author(s):  
Mengran Liu ◽  
Lei Nie ◽  
Shanqiang Li ◽  
Wen Jia ◽  
Lansheng Zhang ◽  
...  
Keyword(s):  
Sound Source ◽  
High Performance ◽  
Practical Significance ◽  
Wave Tube ◽  
Vector Hydrophone ◽  
Good Consistency ◽  
Mems Technology ◽  
New Type ◽  
Working Principle ◽  
Standing Wave Tube

A new type of array MEMS (Microelectro Mechanical Systems) vector hydrophone has been proposed to solve the left-right ambiguity problem that is commonly found in current ones. Meanwhile, the advantages of good sensitivity and low fabrication cost are maintained. The array MEMS vector hydrophone is integrated by four units oriented at different direction angles. By the aid of this kind of vector hydrophone, not only the exact direction of the sound source can be measured, but also the position obtained. The working principle of the array microstructure has been analyzed and simulated. The result shows that the position of the sound source can be well determined. The prototype of the hydrophone is fabricated based on standard MEMS technology, and its performance is tested in a standing wave tube and an anechoic tank. The testing results show that the array hydrophone exhibits a good consistency of all the four units and satisfactory performance. More importantly, this array hydrophone exhibits excellent ability of positioning with the relatively small angle error. Thus, a MEMS hydrophone with multiple functions and relatively high performance is realized, which has important theoretical and practical significance in relevant applications such as the small-size underwater vehicles.

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.

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