scholarly journals Structural Design and Sound Absorption Properties of Nitrile Butadiene Rubber-Polyurethane Foam Composites with Stratified Structure

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 946 ◽  
Author(s):  
Xueliang Jiang ◽  
Zhijie Wang ◽  
Zhen Yang ◽  
Fuqing Zhang ◽  
Feng You ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Structural Design ◽  
Sandwich Structure ◽  
Sound Absorption ◽  
Low Frequency ◽  
Thickness Ratio ◽  
Butadiene Rubber ◽  
Absorption Mechanism ◽  
Nitrile Butadiene Rubber ◽  
Absorption Performance

Sound absorbing composites with stratified structures, including double-layer and sandwich structures, were prepared through the combination of nitrile butadiene rubber (NBR) and polyurethane foam (PUFM). The effects of the thickness ratio of layers, different stratified structures and the variety of fillers on the sound absorption performance of the NBR-PUFM composites and the sound absorption mechanism were studied. The results show that the NBR-PUFM composite with a sandwich structure and thickness ratio of 1:8:1 displays good sound absorption, which could be improved further by adding fillers. Because the airflow resistivity, resonance absorption, interface dissipation and interface reflection were combined organically in the sandwich structure, the composites show excellent low-frequency sound absorption performance. Moreover, the composite also has advantages in cost and functionalization aspects.

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 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.

New acoustical technology of sound absorption based on reverse horn

2016 ◽  
Vol 30 (34) ◽  
pp. 1650403 ◽  
Author(s):  
Yong Yan Zhang ◽  
Jiu Hui Wu ◽  
Song Hua Cao ◽  
Pei Cao ◽  
Zi Ting Zhao
Keyword(s):  
High Frequency ◽  
Sound Absorption ◽  
Mechanical Energy ◽  
Low Frequency ◽  
Acoustic Energy ◽  
Absorption Mechanism ◽  
Structure Changes ◽  
Potential Applications ◽  
Energy Focusing ◽  
The One

In this paper, a novel reverse horn’s sound-absorption mechanism and acoustic energy focusing mechanism for low-frequency broadband are presented. Due to the alternation of the reverse horn’s thickness, the amplitude of the acoustic pressure propagated in the structure changes, which results in growing energy focused in the edge and in the reverse horn’s tip when the characteristic length is equal to or less than a wavelength and the incident wave is compressed. There are two kinds of methods adopted to realize energy dissipation. On the one hand, sound-absorbing materials are added in incident direction in order to overcome the badness of the reverse horn’s absorption in high frequency and improve the overall high-frequency and low-frequency sound-absorption coefficients; on the other hand, adding mass and film in its tip could result in mechanical energy converting into heat energy due to the coupled vibration of mass and the film. Thus, the reverse horn with film in the tip could realize better sound absorption for low-frequency broadband. These excellent properties could have potential applications in the one-dimensional absorption wedge and for the control of acoustic wave.

Theoretical and numerical study of nonlinear acoustic absorbers for low frequency noise control

2021 ◽  
Vol 263 (1) ◽  
pp. 5600-5604
Author(s):  
Min Yang ◽  
Xianhui Li ◽  
Zenong Cai ◽  
Junjuan Zhao ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Averaging Method ◽  
Numerical Study ◽  
Structural Parameters ◽  
Low Frequency ◽  
Frequency Noise ◽  
Flow Equations ◽  
State Response ◽  
Runge Kutta Method ◽  
Absorption Performance

In this paper, the sound absorption characteristics of cubic nonlinear sound-absorbing structures are analyzed by theoretical and numerical methods. The slow flow equations of the system are derived by using complexification averaging method, and the nonlinear equations which describe the steady- state response are obtained. The resulting equations are verified by comparing the results which respectively obtained from complexification-averaging method and Runge-Kutta method. It is helpful to optimize the structural parameters and further improve the sound absorption performance to study the variation of the sound absorption performance of cubic nonlinear structure with its structural parameters.

scholarly journals Sound Absorption Performance of Aluminum Silicate Fiber for Noise and Vibration Reduction of Distribution Transformer

2022 ◽  
Vol 2152 (1) ◽  
pp. 012037
Author(s):  
Qunli Chen ◽  
Wengeng Wu ◽  
Xu Gao ◽  
Yibiao Huang ◽  
Xiangwen Chen ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Plate Thickness ◽  
Low Frequency ◽  
Unit Weight ◽  
Aluminum Silicate ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Absorption Performance ◽  
Cavity Thickness ◽  
Noise And Vibration Reduction

Abstract In view of the low-frequency noise problem in urban substation, the sound absorption (SA) properties of aluminum silicate fibers (ASF) with different materials, unit weight, plate thickness and cavity thickness were tested in this paper. It was found that the high-purity ASF with larger unit weight, plate thickness and cavity thickness had larger low-frequency SA coefficient, which provided technical support for the development of new low-frequency noise reduction materials for substation.

scholarly journals Synthesis and Evaluation of Polyurethane Foam Composites for Enhanced Sound Absorption at Low Frequency

2019 ◽  
Vol 8 (3) ◽  
pp. 6815-6818
Keyword(s):  
Absorption Coefficient ◽  
Polyurethane Foam ◽  
Sound Absorption ◽  
Low Frequency ◽  
Weight Fraction ◽  
Crumb Rubber ◽  
Polyurethane Foams ◽  
Sound Absorption Coefficient ◽  
Filler Materials ◽  
Frequency Range

Polyurethane foams are extensively used as sound absorbing materials in various automobile parts. However, the sound absorption capability of polyurethane foam ispoorin low frequency range. The advancement of technologies to develop newerpolymer composites, provide scope to develop composite polyurethane foam with better sound absorption coefficient in low frequency range. Composite foams are made with two different filler materials as crumb rubber and coconut fiber, in varying weight fraction of up to 2.0%. Density, Sound absorption coefficient, and Noise reduction, measurements were done on all polyurethane foams. The effect offiller additionsto polyurethane foams ondensity and sound absorption coefficient at low frequency are discussed.The 1.4 % crumb rubber polyurethane foam offers the best combination of low density, improved sound absorption coefficient value and noise absorption at low frequency.

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