Sound transmission loss characteristics of unbounded orthotropic sandwich panels in bending vibration considering transverse shear deformation

An approach on the prediction of sound transmission loss for a finite sandwich panel with honeycomb core is described in the paper. The sandwich panel is treated as orthotropic and the apparent bending stiffness in two principal directions is estimated by means of simple tests on beam elements cut from the sandwich panel. Utilizing orthotropic panel theory, together with the obtained bending stiffness in two directions, the sound transmission loss of simply-supported sandwich panel is predicted by the modal expansion method. Simulation results indicated that dimension, orthotropy, and loss factor may play important roles on sound transmission loss of sandwich panel. The predicted transmission loss is compared with measured data and the agreement is reasonable. This approach may provide an efficient tool to predict the sound transmission loss of finite sandwich panels.

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Predicting the Sound Transmission Loss of Honeycomb Panels using the Wave Propagation Approach

Acta Acustica united with Acustica ◽

10.3813/aaa.918466 ◽

2011 ◽

Vol 97 (5) ◽

pp. 869-876 ◽

Cited By ~ 6

Author(s):

Sathish Kumar ◽

Leping Feng ◽

Ulf Orrenius

Keyword(s):

Wave Propagation ◽

Transmission Loss ◽

Plate Theory ◽

Sandwich Panels ◽

Sound Transmission ◽

Structural Vibration ◽

Sound Transmission Loss ◽

Resonance Frequencies ◽

Fluid Coupling ◽

Vibration And Sound Radiation

The sound transmission properties of sandwich panels can be predicted with sufficient degree of accuracy by calculating the wave propagation properties of the structure. This method works well for sandwich panels with isotropic cores but applications to panels with anisotropic cores are hard to find. Honeycomb is an example of anisotropic material which when used as a core, results in a sandwich panel with anisotropic properties. In this paper, honeycomb panels are treated as being orthotropic and the wavenumbers are calculated for the two principle directions. These calculated wavenumbers are validated with the measured wavenumbers estimated from the resonance frequencies of freely hanging honeycomb beams. A combination of wave propagation and standard orthotropic plate theory is used to predict the sound transmission loss of honeycomb panels. These predictions are validated through sound transmission measurements. Passive damping treatment is a common way to reduce structural vibration and sound radiation, but they often have little effect on sound transmission. Visco-elastic damping with a constraining layer is applied to two honeycomb panels with standard and enhanced fluid coupling properties. This enhanced fluid coupling in one of the test panels is due to an extended coincidence range observed from the dispersion curves. The influence of damping treatments on the sound transmission loss of these panels is investigated. Results show that, after the damping treatment, the sound transmission loss of an acoustically bad panel and a normal panel are very similar.

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Study on V-Bending of Aluminium Foam Sandwich Panels

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.181-182.281 ◽

2011 ◽

Vol 181-182 ◽

pp. 281-286 ◽

Cited By ~ 1

Author(s):

Zhen Zhong Sun ◽

Wei Feng He ◽

Hai Bin Chen ◽

Sheng Gui Chen ◽

Rong Yong Li

Keyword(s):

Shear Deformation ◽

Transverse Shear ◽

Final Stage ◽

Sandwich Panels ◽

Core Layer ◽

Aluminium Foam ◽

Transverse Shear Deformation ◽

Acceptable Limit ◽

Air Bending

The forming of the completed aluminium foam sandwich (AFS) panels would determine an improvement in the manufacturing of parts and panels. In this paper the authors have investigated the formability of AFS through experiments. the load versus punch stroke curve and deformation procedures of Aluminium foam sandwiche panels was investigated by performing V-bending experiments. A serious problem encountered in the V-bending was bending-induced large transverse shear deformation of the skin-core layer. It causes the delamination of the AFS. It was found from experimental observations that the large shear defomation progresses rapidly only at the final stage of V-bending. Consequently, the air-bending operation for Aluminium foam sandwiche panels is recommended for suppressing the shear deformation of skin-core layer to within an acceptable limit.

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ON THE SOUND TRANSMISSION LOSS OF CAVITY PANELS AND RESILIENT-MATERIAR-SANDWICH PANELS : Study on Sound Transmission Loss of Building Elements Part 3

Transactions of the Architectural Institute of Japan ◽

10.3130/aijsaxx.116.0_42 ◽

1965 ◽

Vol 116 (0) ◽

pp. 42-51,67

Author(s):

SHINICHI KUGA

Keyword(s):

Transmission Loss ◽

Sandwich Panels ◽

Sound Transmission ◽

Sound Transmission Loss ◽

Building Elements

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Assessments of shear core effects on sound transmission loss through sandwich panels using a two-scale approach

Computers & Structures ◽

10.1016/j.compstruc.2016.11.017 ◽

2017 ◽

Vol 182 ◽

pp. 227-237 ◽

Cited By ~ 8

Author(s):

Z. Zergoune ◽

M.N. Ichchou ◽

O. Bareille ◽

B. Harras ◽

R. Benamar ◽

...

Keyword(s):

Transmission Loss ◽

Sandwich Panels ◽

Sound Transmission ◽

Sound Transmission Loss

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Sound Transmission Loss of Adhesively Bonded Sandwich Panels with Pyramidal Truss Core: Theory and Experiment

International Journal of Applied Mechanics ◽

10.1142/s175882511540013x ◽

2015 ◽

Vol 07 (01) ◽

pp. 1550013 ◽

Cited By ~ 19

Author(s):

C. Shen ◽

Q. C. Zhang ◽

S. Q. Chen ◽

H. Y. Xia ◽

F. Jin

Keyword(s):

Adhesive Bonding ◽

Transmission Loss ◽

Sandwich Panels ◽

Sound Transmission ◽

Homogenization Theory ◽

Sound Insulation ◽

Sound Transmission Loss ◽

Adhesively Bonded ◽

Effective Elastic Constant ◽

Standing Wave Tube

In this paper, an analytical model is developed to investigate sound transmission loss characteristic of adhesively bonded metal sandwich panels with pyramidal lattice truss cores based on 3D elasticity theory. Meanwhile, practical specimen is fabricated to conduct corresponding sound insulation experiment test via a standing wave tube method. The effective elastic constant of truss cores is derived using one homogenization theory on account of equivalent strain energy. It is found that satisfactory agreement is achieved between theoretical solutions and experiment results, and damping effect of adhesive bonding interface between facesheets and core has a great impact on transmission loss. Further parameter investigations demonstrate the significant effect of the elevation and azimuth angles of the pyramidal cores, which can be conveniently changed to tailor the acoustic performance of the sandwich panels in the whole frequency range.

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Sound transmission loss characteristics of sandwich aircraft panels: Influence of nature of core

Journal of Sandwich Structures & Materials ◽

10.1177/1099636216652580 ◽

2016 ◽

Vol 19 (1) ◽

pp. 26-48 ◽

Cited By ~ 21

Author(s):

MP Arunkumar ◽

Jeyaraj Pitchaimani ◽

KV Gangadharan ◽

MC Lenin Babu

Keyword(s):

Sandwich Panel ◽

Transmission Loss ◽

Sheet Material ◽

Low Frequency ◽

Sandwich Panels ◽

Sound Transmission ◽

Sound Transmission Loss ◽

Honeycomb Core ◽

Transmission Characteristics ◽

The Impact

Sandwich panel which has a design involving acoustic comfort is always denser and larger in size than the design involving mechanical strength. The respective short come can be solved by exploring the impact of core geometry on sound transmission characteristics of sandwich panels. In this aspect, the present work focuses on the study of influence of core geometry on sound transmission characteristics of sandwich panels which are commonly used as aircraft structures. Numerical investigation has been carried out based on a 2D model with equivalent elastic properties. The present study has found that, for a honeycomb core sandwich panel in due consideration to space constraint, better sound transmission characteristics can be achieved with lower core height. It is observed that, for a honeycomb core sandwich panel, one can select cell size as the parameter to reduce the weight with out affecting the sound transmission loss. Triangular core sandwich panel can be used for low frequency application due to its increased transmission loss. In foam core sandwich panel, it is noticed that the effect of face sheet material on sound transmission loss is significant and this can be controlled by varying the density of foam.

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