scholarly journals Investigation of Acoustic Properties on Wideband Sound-Absorber Composed of Hollow Perforated Spherical Structure with Extended Tubes and Porous Materials

2020 ◽  
Vol 10 (24) ◽  
pp. 8978
Author(s):  
Dengke Li ◽  
Zhongcheng Jiang ◽  
Lin Li ◽  
Xiaobo Liu ◽  
Xianfeng Wang ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Three Dimensional ◽  
Low Frequency ◽  
Acoustic Properties ◽  
Low Frequencies ◽  
Frequency Sound ◽  
Sound Absorber ◽  
Spherical Structure ◽  
Absorption Performance ◽  
Melamine Foam

Traditional porous media such as melamine foam absorb sound due to their three-dimensional porous struts. However, the acoustic properties at low frequencies are greatly related to its thickness. In this paper, a novel type of thin and lightweight sound absorber composed of melamine foam and hollow perforated spherical structure with extended tubes (HPSET) is introduced to enhance the sound absorption performance at low frequencies. A theoretical model for the normal absorption coefficient of the HPSET with melamine foam is established. Good agreements are observed between the simulated and the experimental results. Compared with the virgin melamine foam, the proposed absorber can greatly improve the low-frequency sound absorption and retain the mid- to high-frequency sound absorption, while the thickness of the proposed absorber is less than 1/28 of the wavelength.

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.

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.

A Compact Hybrid Sound Absorber Using Flexible Micro-Perforated Panel and Piezoelectric Actuator

2013 ◽  
Vol 325-326 ◽  
pp. 8-11
Author(s):  
Wei Guang Zheng ◽  
Ying Feng Lei ◽  
Qi Bai Huang ◽  
Chuan Bing Li
Keyword(s):  
Hybrid System ◽  
Piezoelectric Actuator ◽  
Sound Absorption ◽  
Low Frequency ◽  
Combined Approach ◽  
High Frequencies ◽  
Sound Absorber ◽  
Vibration Effect ◽  
Piezoelectric Patch ◽  
Absorption Performance

This paper presents the concept of a compact hybrid sound absorber, based on a combined approach for sound absorption. A flexible micro-perforated panel (MPP) is used as the passive sound absorber for mid and high frequencies and a piezoelectric patch as the active control actuator for low frequency. The volume of this new absorber is highly reduced compare to conventional hybrid systems which employ porous layer as passive part and loudspeaker as active part. The vibration effect of the MPP in the hybrid system is also considered. Theoretical and experimental results show that the flexible MPP has the potential to dissipate more energy and can be utilized to improve absorption performance of the hybrid system by appropriately selecting its parameters.

scholarly journals Design of Multiple Parallel-Arranged Perforated Panel Absorbers for Low Frequency Sound Absorption

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2099
Author(s):  
Xin Li ◽  
Qianqian Wu ◽  
Ludi Kang ◽  
Bilong Liu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Normal Wave ◽  
Low Frequency ◽  
Approximation Model ◽  
Low Frequencies ◽  
Absorption Bandwidth ◽  
Frequency Sound ◽  
Electrical Analogy ◽  
Wave Incidence

A particular structure that consists of four parallel-arranged perforated panel absorbers (PPAs) is proposed for the low frequency sound absorption within a constraint space. The apertures of the perforated panels are set to ≥1.5 mm, and the number of orifices is much less and therefore easier to be produced in comparison with that of the micro perforated panel (MPP). A simple approximation model by using acoustic-electrical analogy is described to calculate the sound absorption coefficient of such device subject to normal wave incidence. Theoretical and experimental results demonstrate that the device can provide more than one octave sound absorption bandwidth at low frequencies.

scholarly journals Acoustic Properties of Sound Absorber from Modified Polyester with Filler Sodium Bicarbonate

2018 ◽  
Vol 34 (4) ◽  
pp. 2187-2191
Author(s):  
Nasmi Herlina Sari ◽  
Jauhar Fajrin
Keyword(s):  
Absorption Coefficient ◽  
Sodium Bicarbonate ◽  
Acoustic Impedance ◽  
Sound Absorption ◽  
Polyester Resin ◽  
Acoustic Properties ◽  
Acoustic Parameters ◽  
Absorbent Material ◽  
Sound Absorber ◽  
Absorption Performance

The combination of low price, ease of manufacturing and waterproofing characteristics has placed polyester resin as a potential sound absorbent material. Previous studies showed that adding filler material to the blending may increase the acoustics properties of a sound absorbent material. This study aims to investigate the potential of sodium bicarbonate (NaHCO3) to be employed as a filler to improve the acoustic properties of the sound absorber made of polyester resin. Two important acoustic parameters were carefully assessed; absorption coefficient and acoustic impedance. The results showed that the sound absorption performance increased significantly at low and medium frequencies in the presence of NaHCO3 filler in polyester resin. Meanwhile, the use of a back cavity on the absorbent material reduced the sound absorption performance of materials at low and medium frequencies. This suggests that sound absorber made of polyester with sodium bicarbonate filler may be used as an alternative for sound absorber materials.

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.

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