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

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.

Download Full-text

Optimization and Validation of Sound Absorption Performance of 10-Layer Gradient Compressed Porous Metal

Metals ◽

10.3390/met9050588 ◽

2019 ◽

Vol 9 (5) ◽

pp. 588 ◽

Cited By ~ 9

Author(s):

Fei Yang ◽

Xinmin Shen ◽

Panfeng Bai ◽

Xiaonan Zhang ◽

Zhizhong Li ◽

...

Keyword(s):

Finite Element ◽

Finite Element Simulation ◽

Sound Absorption ◽

Search Algorithm ◽

Theoretical Data ◽

Porous Metal ◽

Cuckoo Search ◽

Absorption Coefficients ◽

Element Simulation ◽

Absorption Performance

Sound absorption performance of a porous metal can be improved by compression and optimal permutation, which is favorable to promote its application in noise reduction. The 10-layer gradient compressed porous metal was proposed to obtain optimal sound absorption performance. A theoretical model of the sound absorption coefficient of the multilayer gradient compressed porous metal was constructed according to the Johnson-Champoux-Allard model. Optimal parameters for the best sound absorption performance of the 10-layer gradient compressed porous metal were achieved by a cuckoo search algorithm with the varied constraint conditions. Preliminary verification of the optimal sound absorber was conducted by the finite element simulation, and further experimental validation was obtained through the standing wave tube measurement. Consistencies among the theoretical data, the simulation data, and the experimental data proved accuracies of the theoretical sound absorption model, the cuckoo search optimization algorithm, and the finite element simulation method. For the investigated frequency ranges of 100–1000 Hz, 100–2000 Hz, 100–4000 Hz, and 100–6000 Hz, actual average sound absorption coefficients of optimal 10-layer gradient compressed porous metal were 0.3325, 0.5412, 0.7461, and 0.7617, respectively, which exhibited the larger sound absorption coefficients relative to those of the original porous metals and uniform 10-layer compressed porous metal with the same thickness of 20 mm.

Download Full-text

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.468.134 ◽

2013 ◽

Vol 468 ◽

pp. 134-140 ◽

Cited By ~ 1

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.

Download Full-text

Identification of Acoustic Characteristic Parameters and Improvement of Sound Absorption Performance for Porous Metal

Metals ◽

10.3390/met10030340 ◽

2020 ◽

Vol 10 (3) ◽

pp. 340 ◽

Cited By ~ 1

Author(s):

Xiaocui Yang ◽

Xinmin Shen ◽

Haiqin Duan ◽

Xiaonan Zhang ◽

Qin Yin

Keyword(s):

Experimental Data ◽

Composite Structures ◽

Sound Absorption ◽

Porous Metal ◽

Cuckoo Search ◽

Acoustic Characteristic ◽

Identification Algorithm ◽

Characteristic Parameters ◽

Absorption Performance ◽

Standing Wave Tube

Porous metal is widely used in the fields of sound absorption and noise reduction, and it is a critical procedure to identify acoustic characteristic parameters and to improve sound absorption performances. Based on the constructed theoretical sound absorption model and experimental data, acoustic characteristic parameters of the porous metal were identified through the cuckoo search identification algorithm, and their reliabilities were certified through comparing with these labeled parameters and further experimental validation. By adding the microperforated metal panel in front of the porous metal, a composite sound-absorbing structure was formed, which aimed to improve the sound absorption performance of the original porous metal by optimizing the parameters. Finite element simulation and a standing wave tube measurement were conducted to validate the effectiveness and practicability of the optimal composite sound-absorbing structure. Consistencies among theoretical predictions, simulation results, and experimental data proved the effectiveness of the identification and optimization method. When the target frequency ranges were 100–1000 Hz, 100–2000 Hz, 100–3000 Hz, and 100–4000 Hz. Actual average sound absorption coefficients of the optimal composite structures were 0.5154, 0.6369, 0.6770, and 0.7378, respectively, which exhibited the obvious improvements with a tiny increase in the occupied space and a small addition in weight.

Download Full-text

A Multi-Tone Sound Absorber Based on an Array of Shunted Loudspeakers

Applied Sciences ◽

10.3390/app8122484 ◽

2018 ◽

Vol 8 (12) ◽

pp. 2484 ◽

Cited By ~ 2

Author(s):

Chaonan Cong ◽

Jiancheng Tao ◽

Xiaojun Qiu

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Sound Absorption ◽

Interaction Analysis ◽

Low Frequency ◽

Normal Incidence ◽

Acoustic Properties ◽

The Finite Element Method ◽

Sound Absorber ◽

Modal Solution

It has been demonstrated that a single shunted loudspeaker can be used as an effective low frequency sound absorber in a duct, but many shunted loudspeakers have to be used in practice for noise reduction or reverberation control in rooms, thus it is necessary to understand the performance of an array of shunted loudspeakers. In this paper, a model for the parallel shunted loudspeaker array for multi-tone sound absorption is proposed based on a modal solution, and then the acoustic properties of a shunted loudspeaker array under normal incidence are investigated using both the modal solution and the finite element method. It was found that each shunted loudspeaker can work almost independently where each unit resonates. Based on the interaction analysis, multi-tone absorbers in low frequency can be achieved by designing multiple shunted loudspeakers with different shunt circuits respectively. The simulation and experimental results show that the normal incidence sound absorption coefficient of the designed absorber has four absorption peaks with values of 0.42, 0.58, 0.80, and 0.84 around 100 Hz, 200 Hz, 300 Hz, and 400 Hz respectively.

Download Full-text

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

Applied Sciences ◽

10.3390/app10248978 ◽

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.

Download Full-text