Sound Insulation Property of Warp Knitted Fabrics

2012 ◽  
Vol 535-537 ◽  
pp. 1429-1432
Author(s):  
Kun Yang ◽  
Tian Sheng Ye
Keyword(s):  
Sound Wave ◽  
Sound Insulation ◽  
Test Device ◽  
Insulation Property ◽  
Knitted Fabrics ◽  
Solid Structure ◽  
Thin Structure ◽  
Insulation Effect

In this study, a test device was designed and established for evaluating the sound insulation of fabrics, and six warp knitted fabrics with different parameters were chosen and tested. The results show that these fabrics have different sound insulation effect to various sound wave frequencies, and normally, the fabric with solid structure has better sound insulation effect that the fabric with thin structure, but the effect of latter fabric can be improved by using some treatments.

Analytical higher-order-theories for noise reduction analysis of viscoelastic composite multilayered shells

2021 ◽  
pp. 095440622098233
Author(s):  
A Alaimo ◽  
C Orlando ◽  
S Valvano
Keyword(s):  
Sound Transmission ◽  
Higher Order ◽  
Sound Insulation ◽  
Viscoelastic Layer ◽  
Multilayered Structures ◽  
Viscoelastic Composite ◽  
Damping Behavior ◽  
Shell Models ◽  
Composite Layers ◽  
Insulation Effect

The noise transmission of aeronautical panels is an important phase of the design process of an airplane. In this work an analytical Navier-type solution, based on higher-order layer-wise shell models, is proposed for the analysis of the sound insulation of laminated panels. The considered multilayered structures are laminated with cross-ply composite layers embedded with interlaminar viscoelastic sheets. The use of the soft interlayers permits to have a passive insulation effect in the study of the sound transmission. In order to take into account the frequency depedent properties of a realistic viscoelastic layer, the damping behavior is modeled through a fractional derivative Zener model. The Rayleigh integral method is used to extrapolate the acoustic indicators for the sound transmission analysis. Some results are presented to validate the efficiency of the present approach, comparing the present solutions with others taken from the literature.

Research on the Insulation Performance of Sound-Isolating and Decoupled Tiles

2013 ◽  
Vol 457-458 ◽  
pp. 703-706 ◽  
Author(s):  
De Jin Qian ◽  
Xue Ren Wang ◽  
Xu Hong Miao
Keyword(s):  
Large Scale ◽  
Acoustic Radiation ◽  
Single Point ◽  
Mechanical Vibration ◽  
Sound Insulation ◽  
Acoustic Performance ◽  
Operating Modes ◽  
Insulation Effect ◽  
Vibration And Sound Radiation ◽  
Insulation Performance

The acoustic performance of sound-isolating and decoupled tiles is studied from macroscopic and microscopic. First, the sound absorption and reverse sound insulation performance of sound-isolating and decoupled tiles is studied based on laminated media; then the acoustic decoupling materials influence on acoustic radiation of double cylindrical shell underwater is studied, using a double-layer cylindrical structure of large-scale as experimental model .There are large amount of operating modes designed in this experiment, such as all laying, partial laying, laying and so on. The results show that sound-isolating and decoupled tiles not only have the effect of weakening the absorption of reflections, but also have reverse sound insulation effect, which increases as frequency increases; for single point mechanical vibration, the tiles can effectively inhibit vibration and sound radiation of high frequency in the double shell.

Study on Properties of Foam Concrete Based on Fractal Theory

2011 ◽  
Vol 194-196 ◽  
pp. 1916-1919 ◽  
Author(s):  
Wen Ling Tian ◽  
Jiang Bo Yang ◽  
Xiao Yan Zhao
Keyword(s):  
Fractal Dimension ◽  
Fly Ash ◽  
Thermal Insulation ◽  
Fractal Theory ◽  
High Strength ◽  
Sound Insulation ◽  
Foam Concrete ◽  
Insulation Property ◽  
Foaming Agent ◽  
Thermal Insulation Property

Foam concrete is provided with light weight, thermal insulation, sound insulation and fire resistance, good seismic performance and other characteristics. To improve properties of foam concrete microstructure is studied with the help of fractal theory, fractal dimension related to mechanical properties and thermal performance of foam concrete is calculated by MATLAB language program. The results indicate that the microstructure of foam concrete showed significant fractal character, the fractal dimension is between 1.3 and 2.0. Apparent density, 28d compressive strength, and thermal conductivity decreases with the increase of fly ash and foaming agent content, fractal dimension increased. Formulas of fractal dimension and the fly ash, foaming agent content were established. Foam concrete with low density, high strength, and good thermal insulation property will be prepared conducted by the formulas.

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.

Acoustic performance prediction of a multilayered finite cylinder equipped with porous foam media

2020 ◽  
Vol 26 (11-12) ◽  
pp. 899-912 ◽  
Author(s):  
Hamed Darvish Gohari ◽  
MohamdReza Zarastvand ◽  
Roohollah Talebitooti
Keyword(s):  
Transmission Loss ◽  
Shear Deformation Theory ◽  
Sound Transmission ◽  
Double Fourier Series ◽  
Finite Cylinder ◽  
Sound Insulation ◽  
Transverse Displacement ◽  
Sound Transmission Loss ◽  
Insulation Property ◽  
Longitudinal Modes

This paper presents an analytical model to embed porous materials in a finite cylindrical shell in order to obtain the sound transmission loss coefficient. Although the circumferential modes are considered only for calculating the amount of the transmitted noise through an infinitely long cylinder, the present study employs the longitudinal modes in addition to circumferential ones to analyze the vibroacoustic performance of a simply supported cylinder subjected to the porous core based on the first order shear deformation theory. To achieve this goal, the structure is immersed in a fluid and excited by an acoustic wave. In addition, the acoustic pressures and the displacements are developed in the form of double Fourier series. Since these series consist of infinite modes, it is essential to terminate this process by considering adequate modes. Hence, the convergence checking algorithm is employed in the form of some three-dimensional configurations with respect to length, frequency and radius. Afterwards, some figures are plotted to confirm the accuracy of the present formulation. In these configurations, the obtained sound transmission loss from the present study is compared with that of the infinite one. It is shown that by increasing the length of the structure, the results are approached to sound transmission loss of the infinite shells. Moreover, a new approach is proposed to show the transverse displacement of a finite poroelastic cylinder at different frequencies. Based on the outcomes, it is found that by enhancing the length of the poroelastic cylinder, the amount of the transmitted sound into the structure is reduced at the high frequency domain. However, the sound insulation property of the structure is improved at the low frequency region when the radius of the shell is decreased.

Sound insulation effect of studs within double leaf walls

2014 ◽  
Vol 18 (sup2) ◽  
pp. S2-780-S2-783
Author(s):  
X. F. Huang ◽  
Y. Yang ◽  
Z. X. Yang
Keyword(s):  
Sound Insulation ◽  
Insulation Effect
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