scholarly journals Sound Insulation Performance of Composite Double Sandwich Panels with Periodic Arrays of Shunted Piezoelectric Patches

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 490
Author(s):  
Shande Li ◽  
Di Xu ◽  
Xiaoxun Wu ◽  
Renjie Jiang ◽  
Geman Shi ◽  
...  
Keyword(s):  
Sandwich Structure ◽  
Transmission Loss ◽  
Virtual Work ◽  
Low Frequency ◽  
Broadband Noise ◽  
Sound Insulation ◽  
Periodic Arrays ◽  
Coupled Equations ◽  
Em Method ◽  
Periodic Element

The existing sandwich structure of the aircraft cabin demonstrates a good sound insulation effect in medium and high frequency bands, but poor in the low frequency band. Therefore, we propose an infinite new lightweight broadband noise control structure and study its sound transmission loss (STL). The structure is an orthogonally rib-stiffened honeycomb double sandwich structure with periodic arrays of shunted piezoelectric patches, and demonstrates lighter mass and better strength than the existing sandwich structure. The structure is equivalent according to Hoff’s equal stiffness theory and the effective medium (EM) method. Using the virtual work principle for a periodic element, two infinite sets of coupled equations are obtained. They are solved by truncating them in a finite range until the solution converges. The correctness and validity of the model are verified by using simulation results and theoretical predictions. Eventually, a further study is performed on the factors influencing the STL. All the results demonstrate that the STL in low-frequency can be improved by the structure, and the sound insulation bandwidth is significantly broadened by adding shunted piezoelectric patches. The structure can provide a new idea for the design of broadband sound insulation.

scholarly journals Low-Frequency Broadband Sound Transmission Loss of Infinite Orthogonally Rib-Stiffened Sandwich Structure with Periodic Subwavelength Arrays of Shunted Piezoelectric Patches

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Zhifu Zhang ◽  
Weiguang Zheng ◽  
Qibai Huang
Keyword(s):  
Sandwich Structure ◽  
Transmission Loss ◽  
Virtual Work ◽  
Low Frequency ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Convergence Criterion ◽  
Sound Transmission Loss ◽  
Space Harmonic ◽  
Broadband Sound

This paper studies low-frequency sound transmission loss (STL) of an infinite orthogonally rib-stiffened sandwich structure flexibly connected with periodic subwavelength arrays of finite shunted piezoelectric patches. A complete theoretical model is proposed by three steps. First, the panels and piezoelectric patches on both sides are equivalent to two homogeneous facesheets by effective medium method. Second, we take into account all inertia terms of the rib-stiffeners to establish the governing equations by space harmonic method, separating the amplitude coefficients of the equivalent facesheets through virtual work principle. Third, the expression of STL is reduced. Based on the two prerequisites of subwavelength assumption and convergence criterion, the accuracy and validity of the model are verified by finite element simulations, cited experiments, and theoretical values. In the end, parameters affecting the STL performance of the structure are studied. All of these results show that the sandwich structure can improve the low-frequency STL effectively and broaden the sound insulation bandwidth.

Sound insulation performance of pyramidal truss core sandwich structure with frame

2021 ◽  
pp. 109963622110288
Author(s):  
Yu-Zhou Wang ◽  
Li Ma
Keyword(s):  
Mechanical Properties ◽  
Sandwich Structure ◽  
Transmission Loss ◽  
Low Frequency ◽  
Sound Insulation ◽  
Geometrical Parameters ◽  
Acoustic Performance ◽  
Truss Core ◽  
Pyramidal Truss ◽  
Wave Angle

Recently, sandwich structures have been widely used in different fields because of their good mechanical properties, but these structures are weak in acoustic performance. In this paper, by combining pyramidal truss core sandwich structure with frame, a new structure is proposed with both good mechanical properties and excellent acoustic performance at low frequency. An analytical model of the pyramidal truss core sandwich structure with frame is developed to investigate the sound transmission loss (STL) performance. Finite element method (FEM) is also used to investigate the STL performance at low frequency. The effects of the incident wave angle and the geometrical parameters on the STL of the structure are discussed.

Numerical study for increasement of low frequency sound insulation of double-panel structure using sonic crystals with distributed Helmholtz resonators

2019 ◽  
Vol 33 (14) ◽  
pp. 1950138
Author(s):  
Myong-Jin Kim
Keyword(s):  
Free Space ◽  
Transmission Loss ◽  
Numerical Study ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Sound Insulation ◽  
The Finite Element Method ◽  
Helmholtz Resonators ◽  
Sonic Crystal ◽  
Sonic Crystals

Numerical simulations of the sound transmission loss (STL) of a double-panel structure (DPS) with sonic crystal (SC) comprised of distributed local resonators are presented. The Local Resonant Sonic Crystal (LRSC) consists of “C”-shaped Helmholtz resonator columns with different resonant frequencies. The finite element method is used to calculate the STL of such a DPS. First, the STLs of LRSC in free space and the DPS with LRSC are calculated and compared. It is shown that the sound insulations of the local resonators inserted in the double panel are higher than that in free space for the same size of the SCs and the same number of columns. Next, STL of the DPS in which the SC composed of three columns of local resonators having the same outer and inner diameters but different slot widths are calculated, and a reasonable arrangement order is determined. Finally, the soundproofing performances of DPS with distributed LRSC are compared with the case of insertion of general cylindrical SC for SC embedded in glass wool and not. The results show that the sound insulation of the DPS can be significantly improved in the low frequency range while reducing the total mass without increasing the thickness.

Phononic crystal sandwich for broadband and low frequency acoustic insulation under diffuse field

2021 ◽  
Vol 263 (4) ◽  
pp. 2296-2303
Author(s):  
Natacha Aberkane-Gauthier ◽  
Miguel Moleròn ◽  
Damien Lecoq ◽  
Clément Lagarrigue ◽  
Charles Pézerat ◽  
...  
Keyword(s):  
Transmission Loss ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Core Layer ◽  
Field Measurements ◽  
Wide Frequency Range ◽  
Point Of View ◽  
Sound Insulation ◽  
Acoustic Insulation ◽  
Gap Opening

Light and thin structures exhibiting high sound insulation over a wide frequency range are a major industrial concern, especially in the transport and building sectors. Phononic crystals constitute promising solutions to solve this issue due to their particular dispersion properties. In this work, we build a system consisting of a well-known sandwich panel comprising a soft elastic core layer hosting periodically arranged rigid inclusions. Diffuse field measurements show a huge improvement of the Transmission Loss compared to the system without inclusions. In fact, for this kind of panel, the structured core enables Bragg band-gap opening for guided slow propagating waves leading to low frequency and broadband enhancement of the Transmission Loss. Using a 3cm-thick material we are able to improve the response from 300 Hz on (λ/38 in air). We then develop a finite elements model to achieve a precise description and understanding of the problem. We also propose a numerical tool to analyze the system's band-structures from a vibroacoustic point of view. It proves very useful for the further development of practical solutions.

Study on low frequency sound insulation characteristic of thin acoustic black hole

2021 ◽  
pp. 2150198
Author(s):  
Xiao Lian ◽  
Shengsheng Wang ◽  
Maolin Liu ◽  
Songhui Nie ◽  
Jinfeng Peng ◽  
...  
Keyword(s):  
Black Hole ◽  
Acoustic Waves ◽  
Transmission Loss ◽  
Low Frequency ◽  
Sound Insulation ◽  
Focusing Effect ◽  
Frequency Sound ◽  
Leading Role ◽  
Potential Applications ◽  
Energy Focusing

We use numerical and experimental methods to investigate the low frequency sound insulation characteristic of designed thin acoustic black hole (ABH). The numerical results show that the sound energy focusing effect plays a leading role in low frequency sound insulation of designed ABH, and the reflection at the edge of ABH is the main reason of sound insulation in medium and high frequencies. Experimental results display that the Sound Transmission Loss (STL) of the designed ABH is higher than 30 dB below 700 Hz, which shows that the isolated acoustic waves are more than 95%. The low frequency sound insulation performance of proposed ABHs is much better than the traditional acoustic materials, which has great potential applications for low frequency sound insulation.

Broadband low-frequency noise reduction using Helmholtz resonator-based metamaterial

2021 ◽  
Vol 69 (4) ◽  
pp. 351-363
Author(s):  
Jhalu Gorain ◽  
Chandramouli Padmanabhan
Keyword(s):  
Transmission Loss ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Broadband Noise ◽  
Unit Cell ◽  
Frequency Noise ◽  
Noise Attenuation ◽  
Low Frequency Noise ◽  
Low Frequencies ◽  
Pu Foam

Achieving broadband noise attenuation at low frequencies is still a significant challenge. Helmholtz resonators offer good low-frequency noise attenuation but are effective only over a narrow band; the cavity volume required at these frequencies is also larger. This article proposes a new broadband acoustic metamaterial (AMM) absorber, which uses polyurethane (PU) foam embedded with small-size resonators tuned to different frequencies. The AMM design is achieved in three phases: (1) develop a transfer-matrix-based one-dimensionalmodel for a resonator with intruded neck; (2) use this model to develop a novel band broadeningmethod, to select appropriate resonators tuned to different frequencies; and (3) construct a unit cell metamaterial embedded with an array of resonators into PU foam. A small-size resonator tuned to 415 Hz is modified, by varying the intrusion lengths of the neck, to achieve natural frequencies ranging from 210 to 415 Hz. Using the band broadening methodology, 1 unit cell metamaterial is constructed; its effectiveness is demonstrated by testing in an acoustic impedance tube. The broadband attenuation characteristics of the constructed unit cell metamaterial are shown to match well with the predicted results. To demonstrate further the effectiveness of the idea, a metamaterial is formed using 4 periodic unit cells and is tested in a twin room reverberation chamber. The transmission loss is shown to improve significantly, at low frequencies, due to the inclusion of the resonators.

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.

Sound transmission through a stiff double-panel structure periodically stabilized by negative stiffness module: Theoretical modeling

2020 ◽  
Vol 26 (23-24) ◽  
pp. 2286-2296 ◽  
Author(s):  
Akintoye O Oyelade
Keyword(s):  
Transmission Loss ◽  
Virtual Work ◽  
Elevation Angle ◽  
Low Frequency ◽  
Sound Transmission ◽  
Negative Stiffness ◽  
Negative Element ◽  
Space Harmonics ◽  
Model Predictions ◽  
Analytic Expressions

Analytic expressions are derived for models predicting the influence of periodically spaced structural links on sound transmission through a double-panel structure. The double panel has been configured to have two sets of structural links: a rib stiffener and negative stiffness component. The stiffener is identical and is spaced periodically at a distance. However, the negative element component is shifted by an amount q from the other set. The dynamic equation of the vibroacoustic of the system is formulated in terms of the space harmonics and by the principle of virtual work. The model is validated by comparing the model predictions with the existing result from the literature. Then, influences of the negative element, engineering safety, offset, and elevation angle are investigated. A new antiresonance with a huge sound transmission loss value can be engineered at the low-frequency region when these parameters are varied. In addition, the application of the stiff model is implemented for a periodic acoustic metamaterial structure. The negative stiffness inclusion can prevent wave propagation at low frequency. The periodic structure can be designed to obtain more and wider frequency bandgaps.

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.

Sound transmission loss of sandwich plate with pyramidal truss cores

2018 ◽  
Vol 22 (3) ◽  
pp. 551-571 ◽  
Author(s):  
Dong-Wei Wang ◽  
Li Ma ◽  
Xin-Tao Wang ◽  
Ge Qi
Keyword(s):  
Sandwich Plate ◽  
Transmission Loss ◽  
Virtual Work ◽  
Acoustic Property ◽  
Continuity Condition ◽  
Sound Insulation ◽  
Space Harmonic ◽  
Fluid Structure ◽  
Pyramidal Truss ◽  
Standing Wave Tube

This paper presents the theoretical model of sandwich plate with pyramidal truss cores to investigate the acoustic property of transmission loss. The two-dimensional periodic model is established based on the assumption that the trusses are regarded as Euler-Bernoulli beams. The fluid-structure interaction is considered by imposing velocity continuity condition at fluid-structure interfaces. The periodic governing equations are derived by using space harmonic expansions and the principle of virtual work. Meanwhile, the practical specimens are fabricated by slitting and snap-fit assembly to conduct sound insulation experiment via standing wave tube method. The theoretical result shows satisfactory agreement with experimental data. The numerical discussions are conducted to demonstrate the effects of incident angles and topological parameters which should be helpful for practical design.

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