Wave spectral finite element model for the prediction of sound transmission loss and damping of sandwich panels

2015 ◽  
Vol 158 ◽  
pp. 251-258 ◽  
Author(s):  
Abderrazak Mejdi ◽  
Noureddine Atalla ◽  
Sebastian Ghinet
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Transmission Loss ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Element Model ◽  
Sound Transmission Loss ◽  
Spectral Finite Element

Prediction of Sound Transmission Loss for Finite Sandwich Panels Based on a Test Procedure on Beam Elements

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Zhongchang Qian ◽  
Daoqing Chang ◽  
Bilong Liu ◽  
Ke Liu
Keyword(s):  
Sandwich Panel ◽  
Transmission Loss ◽  
Test Procedure ◽  
Sandwich Panels ◽  
Sound Transmission ◽  
Expansion Method ◽  
Bending Stiffness ◽  
Sound Transmission Loss ◽  
Modal Expansion ◽  
Beam Elements

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.

scholarly journals Dynamic Analysis of Tapered Thin-Walled Beams Using Spectral Finite Element Method

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yiping Shen ◽  
Zhijun Zhu ◽  
Songlai Wang ◽  
Gang Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Wind Turbine ◽  
Element Model ◽  
Rotor Blades ◽  
Mode Shapes ◽  
Modal Frequency ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
Spectral Finite Element

Tapered thin-walled structures have been widely used in wind turbine and rotor blade. In this paper, a spectral finite element model is developed to investigate tapered thin-walled beam structures, in which torsion related warping effect is included. First, a set of fully coupled governing equations are derived using Hamilton’s principle to account for axial, bending, and torsion motion. Then, the differential transform method (DTM) is applied to obtain the semianalytical solutions in order to formulate the spectral finite element. Finally, numerical simulations are conducted for tapered thin-walled wind turbine rotor blades and validated by the ANSYS. Modal frequency results agree well with the ANSYS predictions, in which approximate 30,000 shell elements were used. In the SFEM, one single spectral finite element is needed to perform such calculations because the interpolation functions are deduced from the exact semianalytical solutions. Coupled axial-bending-torsion mode shapes are obtained as well. In summary, the proposed spectral finite element model is able to accurately and efficiently to perform the modal analysis for tapered thin-walled rotor blades. These modal frequency and mode shape results are important to carry out design and performance evaluation of the tapered thin-walled structures.

Performance assessment of rigid polyurethane foam core sandwich panels under blast loading

2019 ◽  
Vol 11 (1) ◽  
pp. 109-130 ◽  
Author(s):  
Hosein Andami ◽  
Hamid Toopchi-Nezhad
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Polyurethane Foam ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Element Model ◽  
Polyurethane Foams ◽  
Compression Tests ◽  
Foam Layer ◽  
The Finite Element Model

The performance of rigid polyurethane foams, as an energy absorbent core of sandwich panels covered with two exterior steel sheets, was investigated numerically through finite element methods. After verifying the finite element model, numerical studies were conducted to investigate the role of thickness and density of the foam layer in the response behavior of sandwich panels under blast loads. A set of cylindrical polyurethane foam specimens were manufactured at five different nominal densities, 90, 140, 175, 220, and 250 kg/m3, and their stress–strain curves were evaluated using uniaxial compression tests. The test data were then employed to define characteristics of the polyurethane foams in the finite element model. Based on the results of finite element analysis runs, the optimum density of the foam layer was determined by assessing two response parameters including the peak pressure transmitted to the back face of the foam layer and the maximum deflection of sandwich panel. These response parameters were found to be affected differently by variations in the density of the foam layer within the panel. An increase in the thickness of the foam layer, to a certain extent, was found to be beneficial to the mitigation capability of sandwich panel.

scholarly journals Development of a finite element model for the simulation of parabolic impact of sandwich panels

2015 ◽  
Vol 94 ◽  
pp. 01018 ◽  
Author(s):  
Karthik Ram Ramakrishnan ◽  
Sandra Guérard ◽  
Laurent Mahéo ◽  
Krishna Shankar ◽  
Philippe Viot
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sandwich Panels ◽  
Element Model

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

2011 ◽  
Vol 97 (5) ◽  
pp. 869-876 ◽  
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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