scholarly journals Research on sound absorption properties of hydrogenated carboxyl nitrile rubber/four-hole hollow polyester fibre composites

2021 ◽  
Vol 72 (02) ◽  
pp. 117-125
Author(s):  
JIE HONG
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Polyester Fibre ◽  
Low Frequency ◽  
Nitrile Rubber ◽  
Engineering Practice ◽  
Negative Effects ◽  
Absorption Properties ◽  
The Matrix ◽  
Absorption Performance

A series composite was prepared by adding hydrogenated carboxyl nitrile rubber (abbreviated HXNBR) as the matrix and four-hole hollow polyester (abbreviated FHHPF) as the reinforcement. The sound absorption properties of these composites were studied. The results show that with the increasing of FHHPF quantity, the storage modulus increases and the loss factor decreases gradually. On the contrary, the sound absorption performance of the composite was improved continuously. Composite with 40% FHHPF in 1 mm thickness is the best. The sound absorption coefficient reached to 0.651 at 2500 Hz and the effective frequency range of absorption coefficient above 0.2 was 1750-2500 Hz. When the amount of FHHPF increased to 50%, negative effects of overuse shown up, that led to the decreasing of the sound absorption property. With a constant mass ratio 70/30 of HXNBR/FHHPF composite, the sound absorption performance can be enhanced by changing its thickness. However, the improvement was smaller after the thickness increased to 2 mm. When increasing the thickness above 2 mm, the improvement of sound absorption performance tended to move to the middle and low frequency. In the meantime, the tensile mechanical properties of the composite were significantly improved by adding FHHPF. Tensile tenacity was improved greatly and the breaking elongation is significantly decreased. The deformation of the composite was smaller and more stable, which was beneficial for the actual engineering practice.

scholarly journals Sound absorption properties of multi-layer structural composite materials based on waste corn husk fibers

2020 ◽  
Vol 15 ◽  
pp. 155892502091086
Author(s):  
Lihua Lyu ◽  
Jing Lu ◽  
Jing Guo ◽  
Yongfang Qian ◽  
Hong Li ◽  
...  
Keyword(s):  
Composite Materials ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Absorption Properties ◽  
Cavity Depth ◽  
Air Cavity ◽  
Corn Husk ◽  
Structural Composite

In order to find a reasonable way to use the waste corn husk, waste degummed corn husk fibers were used as reinforcing material in one type of composite material. And polylactic acid particles were used as matrix material. The composite materials were prepared by mixing and hot-pressing process, and they were processed into the micro-slit panel. Then, the multi-layer structural sound absorption composite materials were prepared sequentially by micro-slit panel, air cavity, and flax felt. Finally, the sound absorption properties of the multi-layer structural composite materials were studied by changing flax felt thickness, air cavity depth, slit rate, and thickness of micro-slit panel. As the flax felt thickness varied from 0 to 10 mm in 5 mm increments, the peak of sound absorption coefficient shifted to low frequency. The sound absorption coefficient in the low frequency was improved with the air cavity depth varied from 0 to 10 mm in 5 mm increments. With the slit rate increased from 3% to 7% in 2% increments, the peak of sound absorption coefficient shifted to high frequency. With the thickness of micro-slit panel increased from 2 to 6 mm in 2 mm increments, the sound absorption bandwidth was broaden, and the peak of sound absorption coefficient was increased and shifted to low frequency. Results showed that the highest sound absorption coefficient of the multi-layer structural composite materials was about 1 under the optimal process conditions.

Preparation and Low Frequency Sound Absorption Properties of Silicate Composite Material

2012 ◽  
Vol 482-484 ◽  
pp. 1338-1342 ◽  
Author(s):  
Long Gui Peng ◽  
Guang Cheng Zhang ◽  
Xing Guo Yu ◽  
Ying Li
Keyword(s):  
Composite Material ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
High Efficiency ◽  
Low Frequency ◽  
Thin Wall ◽  
Absorption Properties ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Frequency Sound

The silicate based low frequency sound absorption composite material was prepared with powdery polymethacrylimide (PMI) foam as filler. The effects of the amounts of PMI and pore-forming agent, and water-cement ratio on sound absorption properties of composite material were researched. Sound absorption coefficient was characterized by standing wave tube, and micro structure of composite material was analyzed by scanning electron microscope. The results show that: when the amounts of PMI and pore-forming agent are 2.5wt% and 0.04wt%, respectively, and water cement ratio is 0.55, the average value of the absorption coefficient on the sound （≤1000Hz）can up to 0.35. Resonating sound absorption structure formed by micro pore of the silicate and thin wall cavity of PMI in composite materials is beneficial to high efficiency absorption to low frequency sound.

scholarly journals Study of the Sound Absorption Performance of Ethylene-Vinyl Acetate Foam Materials

2019 ◽  
Vol 25 (4) ◽  
pp. 427-432
Author(s):  
Wei GONG ◽  
Yu Long MA ◽  
Da Ming BAN ◽  
Xiao Gang YIN ◽  
Li HE ◽  
...  
Keyword(s):  
Cell Wall ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Ethylene Vinyl Acetate ◽  
Foam Material ◽  
Pore Filling ◽  
Absorption Effect ◽  
Absorption Performance ◽  
Peak Value

Ethylene-Vinyl Acetate (EVA) polymer foam was prepared using a mold for this investigation. The effect of the cell structure parameters and pore filling gas type on the sound absorption performance of the EVA foam materials were analyzed in terms of their sound absorption capability. The results show that the cell size, cell wall thickness and pore filling gas type have significant influence on the sound absorption performance. When the cell size is 71.3 μm, at low frequency (1000 Hz) the absorption coefficient was the largest at 0.487 and the absorption effect was good. With the increase of the cell wall thickness, the peak value of the sound absorption coefficient first increased and then decreased, and gradually transferred to the low frequency area. When the cell wall thicknesses were 14.3 μm, the foam material had optimal sound absorption properties. The cell filling gas was hydrogen, the EVA foam material had optimal sound absorption effect, and the sound absorption peak value was 0.553 at 800 Hz in the low frequency range (Ⅰ), the sound absorption performance of the foamed materials was ideal.

scholarly journals Preparation and sound absorption properties of barium titanate/nitrile butadiene rubber-polyurethane foam composites with stratified structure

RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 20968-20975 ◽  
Author(s):  
Xueliang Jiang ◽  
Zhijie Wang ◽  
Zhen Yang ◽  
Fuqing Zhang ◽  
Feng You ◽  
...  
Keyword(s):  
Barium Titanate ◽  
Polyurethane Foam ◽  
Double Layer ◽  
Sound Absorption ◽  
Low Frequency ◽  
Butadiene Rubber ◽  
Absorption Properties ◽  
Frequency Sound ◽  
Pu Foam ◽  
Absorption Performance

BT/NBR-PU foam composites with two different stratified structures including double-layer and alternating multilayered have excellent low-frequency sound absorption performance.

scholarly journals STUDY AND ANALYSIS ON SOUND ABSORBING AND NOISE REDUCING PERFORMANCE OF TIMBER CONSTRUCTION WALL BASED ON ACOUSTIC SPIRAL MATASURFACE

Wood Research ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 341-352
Author(s):  
Haiyan Fu ◽  
Xinyue Zhao ◽  
Patrick Adjei ◽  
Zheng Wang ◽  
Xiaoli Wu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Impedance Tube ◽  
Frequency Sound ◽  
Timber Construction ◽  
Absorption Performance ◽  
Impedance Tube Method ◽  
Structural Layer

Based on acoustic spiral metasurface, a spiral structural layer was designed to apply to timber construction interior wall. The sound absorption coefficient was measured by impedance tube method and compared with Helmholtz resonance structural layer, solid structural layer and air layer in traditional wall. The results show that the combination of the spiral structural layer and the wall can optimize the sound absorption performance of the wall in the medium and low frequency. Without reducing the overall sound-absorbing performance of the wall, can achieve perfect sound absorption in some medium and low frequency sound bands.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

Sound absorption performance of flexible polyurethane/silicon dioxide perforated coating composites

2021 ◽  
pp. 004051752110155
Author(s):  
Min Peng ◽  
Xiaoming Zhao ◽  
Weibin Li
Keyword(s):  
Silicon Dioxide ◽  
Sound Absorption ◽  
Woven Fabric ◽  
Perforation Rate ◽  
Cavity Depth ◽  
Resonant Frequencies ◽  
The Matrix ◽  
Absorption Performance ◽  
Traditional Sense ◽  
Flexible Polyurethane

Perforated materials in the traditional sense are rigid, usually dense, costly and inflexible. For this study, polyester/cotton blended woven fabric as the base fabric, nano-SiO2 (silicon dioxide) as the functional particles and PU (polyurethane) as the matrix were selected. Accordingly, flexible PU/SiO2 perforated coating composites with different process parameters were developed. The influence of the nano-SiO2 content, perforation diameter, perforation rate, number of fiber felt layers and cavity depth on the sound absorption coefficient were investigated. The resonant frequencies of materials with different cavity depths were evaluated by both theoretical calculation and experimental method. It was found that the flexible perforated composite has good sound absorption and mechanical properties, and has great potential for applications requiring soft and lightweight sound absorption materials.

Realizing high-efficiency low frequency sound absorption of underwater meta-structures by acoustic siphon effect

2021 ◽  
pp. 2150319
Author(s):  
Li Bo Wang ◽  
Cheng Zhi Ma ◽  
Jiu Hui Wu ◽  
Chong Rui Liu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
High Efficiency ◽  
Physical Mechanism ◽  
Low Frequency ◽  
Area Ratio ◽  
Underwater Acoustic ◽  
Element Simulation ◽  
Average Absorption Coefficient ◽  
New Perspective

The underwater acoustic siphon effect is proposed in this work, which aims to reveal the basic physical mechanism of high-efficiency sound absorption in meta-structures composed of multiple detuned units. Furthermore, the influence of the area ratio on the underwater acoustic siphon effect is then investigated by finite element simulation (FES) and theoretical calculation. On this basis, a meta-structure with the maximum absorption coefficient of almost 100% and average absorption coefficient of 80% at 600–1400 Hz is achieved. The underwater acoustic siphon effect could provide a better understanding of high-efficiency sound absorption and offer a new perspective in controlling underwater noises.

scholarly journals Study on the sound absorption behavior of multi-component polyester nonwovens: experimental and numerical methods

2018 ◽  
Vol 89 (16) ◽  
pp. 3342-3361 ◽  
Author(s):  
Tao Yang ◽  
Ferina Saati ◽  
Kirill V Horoshenkov ◽  
Xiaoman Xiong ◽  
Kai Yang ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Absorption Coefficient ◽  
Empirical Model ◽  
Surface Impedance ◽  
Sound Absorption ◽  
Low Frequency ◽  
Accurate Method ◽  
Small Error ◽  
Sound Absorption Coefficient ◽  
Acoustical Properties

This study presents an investigation of the acoustical properties of multi-component polyester nonwovens with experimental and numerical methods. Fifteen types of nonwoven samples made with staple, hollow and bi-component polyester fibers were chosen to carry out this study. The AFD300 AcoustiFlow device was employed to measure airflow resistivity. Several models were grouped in theoretical and empirical model categories and used to predict the airflow resistivity. A simple empirical model based on fiber diameter and fabric bulk density was obtained through the power-fitting method. The difference between measured and predicted airflow resistivity was analyzed. The surface impedance and sound absorption coefficient were determined by using a 45 mm Materiacustica impedance tube. Some widely used impedance models were used to predict the acoustical properties. A comparison between measured and predicted values was carried out to determine the most accurate model for multi-component polyester nonwovens. The results show that one of the Tarnow model provides the closest prediction to the measured value, with an error of 12%. The proposed power-fitted empirical model exhibits a very small error of 6.8%. It is shown that the Delany–Bazley and Miki models can accurately predict surface impedance of multi-component polyester nonwovens, but the Komatsu model is less accurate, especially at the low-frequency range. The results indicate that the Miki model is the most accurate method to predict the sound absorption coefficient, with a mean error of 8.39%.

scholarly journals Hybrid acoustic metamaterial as super absorber for broadband low-frequency sound

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yufan Tang ◽  
Shuwei Ren ◽  
Han Meng ◽  
Fengxian Xin ◽  
Lixi Huang ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Functional Materials ◽  
Theoretical Method ◽  
Acoustic Metamaterials ◽  
Mechanical Stiffness ◽  
Acoustic Metamaterial ◽  
Frequency Sound

Abstract A hybrid acoustic metamaterial is proposed as a new class of sound absorber, which exhibits superior broadband low-frequency sound absorption as well as excellent mechanical stiffness/strength. Based on the honeycomb-corrugation hybrid core (H-C hybrid core), we introduce perforations on both top facesheet and corrugation, forming perforated honeycomb-corrugation hybrid (PHCH) to gain super broadband low-frequency sound absorption. Applying the theory of micro-perforated panel (MPP), we establish a theoretical method to calculate the sound absorption coefficient of this new kind of metamaterial. Perfect sound absorption is found at just a few hundreds hertz with two-octave 0.5 absorption bandwidth. To verify this model, a finite element model is developed to calculate the absorption coefficient and analyze the viscous-thermal energy dissipation. It is found that viscous energy dissipation at perforation regions dominates the total energy consumed. This new kind of acoustic metamaterials show promising engineering applications, which can serve as multiple functional materials with extraordinary low-frequency sound absorption, excellent stiffness/strength and impact energy absorption.

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