A composite and deformable honeycomb acoustic metamaterial

2018 ◽  
Vol 32 (20) ◽  
pp. 1850204 ◽  
Author(s):  
Nansha Gao ◽  
Hong Hou ◽  
Jiu Hui Wu
Keyword(s):  
Transmission Loss ◽  
Tensile Deformation ◽  
Ethylene Vinyl Acetate ◽  
Sound Insulation ◽  
Frequency Range ◽  
Low Frequencies ◽  
Acoustic Metamaterial ◽  
Copolymer Films ◽  
Insulation Effect ◽  
Experiment Analysis

This paper reports the design of a deformable honeycomb acoustic metamaterial, which consists of honeycomb structures and ethylene-vinyl acetate (EVA) copolymer films stacked on each other. The FEA results agree well with the experiment analysis, and it is proved that the proposed structure can break the acoustic mass law below 1000 Hz. This paper reveals that dislocation, compression, and tensile deformation can regulate the sound transmission loss (STL) in a wider frequency range. It is concluded that the STL of a bilayer structure is, on average, 10 dB higher than that of a monolayer structure at low-frequencies. When the dislocation distance b = 1.5 mm, the corresponding STLs reach their maximum values. The FEA and experiment results prove that compression and tensile deformation can considerably improve the sound insulation effect. Such a deformable honeycomb acoustic metamaterial with high STL provides a new concept for engineering noise control.

Plate-type metamaterials for extremely broadband low-frequency sound insulation

2018 ◽  
Vol 32 (03) ◽  
pp. 1850019 ◽  
Author(s):  
Xiaopeng Wang ◽  
Xinwei Guo ◽  
Tianning Chen ◽  
Ge Yao
Keyword(s):  
Transmission Loss ◽  
Structural Parameters ◽  
Low Frequency ◽  
Thin Plates ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Low Frequencies ◽  
Acoustic Metamaterial ◽  
Unit Cells ◽  
Plate Type

A novel plate-type acoustic metamaterial with a high sound transmission loss (STL) in the low-frequency range ([Formula: see text]1000 Hz) is designed, theoretically proven and then experimentally verified. The thin plates with large modulus used in this paper mean that we do not need to apply tension to the plates, which is more applicable to practical engineering, the achievement of noise reduction is better and the installation of plates is more user-friendly than that of the membranes. The effects of different structural parameters of the plates on the sound-proofed performance at low-frequencies were also investigated by experiment and finite element method (FEM). The results showed that the STL can be modulated effectively and predictably using vibration theory by changing the structural parameters, such as the radius and thickness of the plate. Furthermore, using unit cells of different geometric sizes which are responsible for different frequency regions, the stacked panels with thickness [Formula: see text]16 mm and weight [Formula: see text]5 kg/m2 showed high STL below 2000 Hz. The acoustic metamaterial proposed in this study could provide a potential application in the low-frequency noise insulation.

scholarly journals Non-Wovens as Sound Reducers

2018 ◽  
Vol 55 (2) ◽  
pp. 64-76
Author(s):  
D. Belakova ◽  
A. Seile ◽  
S. Kukle ◽  
T. Plamus
Keyword(s):  
Absorption Coefficient ◽  
Surface Density ◽  
Sound Absorption ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Material Structure ◽  
Sound Transmission Loss ◽  
Sound Waves ◽  
Frequency Range

Abstract Within the present study, the effect of hemp (40 wt%) and polyactide (60 wt%), non-woven surface density, thickness and number of fibre web layers on the sound absorption coefficient and the sound transmission loss in the frequency range from 50 to 5000 Hz is analysed. The sound insulation properties of the experimental samples have been determined, compared to the ones in practical use, and the possible use of material has been defined. Non-woven materials are ideally suited for use in acoustic insulation products because the arrangement of fibres produces a porous material structure, which leads to a greater interaction between sound waves and fibre structure. Of all the tested samples (A, B and D), the non-woven variant B exceeded the surface density of sample A by 1.22 times and 1.15 times that of sample D. By placing non-wovens one above the other in 2 layers, it is possible to increase the absorption coefficient of the material, which depending on the frequency corresponds to C, D, and E sound absorption classes. Sample A demonstrates the best sound absorption of all the three samples in the frequency range from 250 to 2000 Hz. In the test frequency range from 50 to 5000 Hz, the sound transmission loss varies from 0.76 (Sample D at 63 Hz) to 3.90 (Sample B at 5000 Hz).

Adjustable sound insulation frequency band through the combination of membrane-type acoustic metamaterial array

2021 ◽  
Vol 263 (1) ◽  
pp. 5869-5877
Author(s):  
Xiang Wu ◽  
TengLong Jiang ◽  
JianWang Shao ◽  
GuoMing Deng ◽  
Chang Jin
Keyword(s):  
Thin Films ◽  
Frequency Band ◽  
Transmission Loss ◽  
Structural Parameters ◽  
Sound Insulation ◽  
Acoustic Metamaterials ◽  
Additional Mass ◽  
Acoustic Metamaterial ◽  
Material Parameters ◽  
Membrane Type

Membrane-type acoustic metamaterials are thin films or plates composed of periodic units with small additional mass. A large number of studies have shown that these metamaterials exhibit tunable anti-resonance, and their transmission loss values are much higher than the corresponding quality laws. At present, most researches on membrane-type acoustic metamaterials focus on the unit cell, and the sound insulation frequency band can only be adjusted by adjusting the structural parameters and material parameters. In this paper, two kinds of acoustic metamaterials with different structures are designed, which are the center placement of the mass and the eccentric placement of the mass.The two structures have different sound insulation characteristics. By designing different array combinations of acoustic metamaterials, the sound insulation peaks of different frequency bands are obtained. This paper studies the corresponding combination law, and effectively realizes the adjustable sound insulation frequency band.

Transmission Loss of Membrane-Type Acoustic Metamaterial with Negative Effective Mass

2017 ◽  
Vol 898 ◽  
pp. 1749-1756 ◽  
Author(s):  
Guo Chang Lin ◽  
Song Qiao Chen ◽  
Yu Liang Li ◽  
Hui Feng Tan
Keyword(s):  
Effective Mass ◽  
Transmission Loss ◽  
Mass Density ◽  
Small Mass ◽  
Equivalent Model ◽  
Sound Insulation ◽  
Rubber Membrane ◽  
Acoustic Metamaterial ◽  
Spring Force ◽  
Membrane Type

The transmission loss (TL) of membrane-type acoustic metamaterials consisting of small mass and rubber membrane was studied. By establishing a mass-spring equivalent model of metamaterial structural unit, which regards rubber membrane as having the dual role of damping force and spring force, we demonstrated that effective mass density of this membrane-type acoustic metamaterial was negative in the band gap range by theoretical analysis. Based on the theory of plane wave propagation, we studied the sound insulation of this membrane-type acoustic metamaterial. The result showed that membrane-type metamaterial was based on the principle of dipole resonance, which made the membrane-type acoustic metamaterial appear high reflection and low transmission phenomenon so as to achieve the aim of reducing noise. By optimal design, the sound attenuation frequency range of this membrane-type acoustic metamaterial was reduced to 20Hz-100Hz, greatly enhancing the ability of this metamaterial in terms of low-frequency sound insulation. We obtained the distribution of sound intensity at the optimum transmission frequency and the best reflection frequency by coupled acoustic-structural analysis. The best sound insulation frequency was matched with the second order and the third order eigenfrequency of this membrane-type acoustic metamaterial unit, and the strain energy was concentrated at the joint of small mass and the membrane. The total sound insulation of acoustic metamaterial plate was better than the single metamaterial unit.

Low frequency acoustic properties of a honeycomb-silicone rubber acoustic metamaterial

2017 ◽  
Vol 31 (11) ◽  
pp. 1750118 ◽  
Author(s):  
Nansha Gao ◽  
Hong Hou
Keyword(s):  
Silicone Rubber ◽  
Transmission Loss ◽  
Layer Structure ◽  
Low Frequency ◽  
Sound Transmission ◽  
Honeycomb Structure ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Control Zone ◽  
Acoustic Metamaterial

In order to overcome the influence of mass law on traditional acoustic materials and obtain a lightweight thin-layer structure which can effectively isolate the low frequency noises, a honeycomb-silicone rubber acoustic metamaterial was proposed. Experimental results show that the sound transmission loss (STL) of acoustic metamaterial in this paper is greatly higher than that of monolayer silicone rubber metamaterial. Based on the band structure, modal shapes, as well as the sound transmission simulation, the sound insulation mechanism of the designed honeycomb-silicone rubber structure was analyzed from a new perspective, which had been validated experimentally. Side length of honeycomb structure and thickness of the unit structure would affect STL in damping control zone. Relevant conclusions and design method provide a new concept for engineering noise control.

A membrane-type acoustic metamaterial muffler

2017 ◽  
Vol 31 (08) ◽  
pp. 1750049 ◽  
Author(s):  
Fang Wang ◽  
Tianning Chen ◽  
Xiaopeng Wang ◽  
Kai Bao ◽  
Lele Wan
Keyword(s):  
Transmission Loss ◽  
Low Frequency ◽  
Acoustic Metamaterials ◽  
Acoustic Transmission ◽  
Frequency Range ◽  
Transmission Performance ◽  
Acoustic Metamaterial ◽  
Dynamic Mass ◽  
Membrane Type ◽  
Theoretical Results

Membrane-type acoustic metamaterials (MAMs) with negative dynamic mass have demonstrated the effects in the sound transmission loss (STL) at low-frequency range. This research aims to design a membrane-type acoustic metamaterial muffler (MAMM) based on the present MAMs, and to solve the problem that airflow cannot flow unimpededly in the channel once using the MAMs. For a better understanding of MAMM, the resonance frequency of the membrane was calculated and simulation was used to study the acoustic transmission performance of the MAMM. The simulation results were verified in comparison with the theoretical results of the membrane. This MAMM reduced the structural size of muffler compared with the traditional Helmholtz muffler and expand muffler, which can find application for the MAMs in acoustic absorption and noise control.

scholarly journals Research on the Sound Insulation Properties of Membrane-type Acoustic Metamaterials

2021 ◽  
Vol 252 ◽  
pp. 02028
Author(s):  
Jinyu Hao ◽  
Sheng Guo ◽  
Jian Cheng ◽  
Zhaopin Hu ◽  
Hongyu Cui
Keyword(s):  
Cell Structure ◽  
Sound Insulation ◽  
Frequency Noise ◽  
Acoustic Metamaterials ◽  
Medium Frequency ◽  
Low Frequencies ◽  
Acoustic Metamaterial ◽  
Membrane Type ◽  
Insulation Performance ◽  
Excessive Noise

Low- and medium-frequency noise from ship cabins is difficult to control effectively. Excessive noise can seriously affect the acoustic stealth performance of ships. A novel membrane-type acoustic metamaterial is proposed in this paper with light weight and good sound insulation performance at low frequencies. The sound insulation performance of the metamaterial structure is analysed by using the acoustic-solid coupling module in COMSOL software. Then, the ability to change the sound insulation performance of membrane-type acoustic metamaterials with cell structure and material parameters is obtained. The research results in this paper provide powerful technical support for noise control in ship cabins.

Reduction of Sound Transmission Through Finite Clamped Metamaterial-Based Double-Wall Sandwich Plates with Poroelastic Cores

2019 ◽  
Vol 105 (5) ◽  
pp. 850-868
Author(s):  
Jingru Li ◽  
Peng Yang ◽  
Sheng Li
Keyword(s):  
Vibration Isolation ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Sandwich Plates ◽  
Low Frequencies ◽  
Finite Structures ◽  
The Galerkin Method ◽  
Insulation Performance ◽  
Double Wall

Finite structures play a more realistic role in applications designed for sound and vibration isolation. Doublepanel structure with poroelastic cores is able to exhibit a superior sound insulation performance in mid-high frequency range, while is relatively inferior to isolate waves at low frequencies. In order to further reduce sound transmission at low frequencies and cater for the actual situation, this paper decides to introduce the metamaterial concept into finite double-wall sandwich plates and presents an analytical model to calculate the sound transmission loss through the metamaterial-based double-panel with fully clamped boundary conditions. The metamaterial-based double-wall sandwich plates are constructed by replacing the bare panel with the metamaterial plate, consisting of a homogeneous plate and periodically attached local resonators. Biot's theory is used to examine the wave propagation in the poroelastic medium. The vibro-acoustic problem of the proposed sandwich plate is solved by employing the modal superposition theory and the Galerkin method. Numerical results show that the sound transmission is significantly reduced at low frequencies. Unique phenomena caused by attached local resonators are explained and the eff ects of resonator inerter, incident angles and damping on the sound insulation properties are also studied.

scholarly journals A Theoretical Investigation on Sound Transmission Loss through Multi-walled Plates with Air Space

2019 ◽  
pp. 1-8
Author(s):  
Toshiaki Natsuki ◽  
Jun Natsuki
Keyword(s):  
Transmission Loss ◽  
Design Method ◽  
Low Frequency ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Layer Structures ◽  
Air Space ◽  
Air Layers ◽  
Insulation Effect

In this study, an analytical model is proposed to investigate the sound transmission loss through multi-walled plates with air layers or decompression air layers, under the diffuse incidence field. Using the present approach, the influences of various parameters, such as the wall thickness, the decompressed air and the thickness of air space, on the sound transmission loss through are simulated and discussed in detail. It is seen that, due to the wave frequency of mass-air-mass resonance between double-walled glass plates, the sound transmission loss of the plates can be improved at low frequency range. The sound transmission loss tends to increase with decreasing air pressure because the sound is not transmitted through vacuum space. The design method can be used to investigate the effect of various geometric and material parameters on the sound transmission loss. The advantage of the simulation procedure is easily used for designing the layer structures with different parameter to improve the sound insulation effect.

scholarly journals Design of Nonwoven Carpets to Upgrade Sound Isolation Features in Automobiles

2014 ◽  
Vol 14 (4) ◽  
pp. 270-280 ◽  
Author(s):  
Raziye Atakan ◽  
Hale Karakaş ◽  
Serdar Sezer ◽  
Süleyman İpek ◽  
İpek Aravi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Sound Absorption ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Frequency Range ◽  
Absorption Coefficients ◽  
Floor Coverings ◽  
Effective Part ◽  
Heavy Layer

Abstract With the increases of the expected properties of textile products, better and advanced new designs are being created. Textiles used in vehicles are increasing, and the current performance of the expectations bar is determined by automobile manufacturers. While meeting the expectations of users in the vehicle mechanically, but also disturbing the user during operation of the mechanical properties of this ratio should be minimized. This study was intended to minimize sound transmission of nonwoven textile components, which are used in cars as silencer parts. For that purpose, four different models were developed in this study. First model consists of three designs for baggage carpets. Second model has six designs for floor coverings. Third model comprises two designs inner dash felt and finally fourth model includes two designs of hood liners. The acoustical absorption coefficients and transmission loss of these carpets were tested and evaluated in the frequency range of 16-6300 Hz. The measurements demonstrated that nonwoven layer is a very significant and effective part of a carpet due to its contribution in the sound isolation. With this study, it has been determined which layer has better performance on sound absorption and transmission loss among different carpet types. A combination of heavy layer and nonwoven layer carpets is found to be benefit for noise and sound insulation.

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