Parametric Study of Noise Transmission Loss of Damped Sandwich Structures

2008 ◽  
Author(s):  
Mohamed Guerich ◽  
Samir Assaf
Keyword(s):  
Parametric Study ◽  
Transmission Loss ◽  
Sandwich Structures ◽  
Noise Transmission

Optimization of Noise Transmission Through Sandwich Structures

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Mohamed Guerich ◽  
Samir Assaf
Keyword(s):  
Sandwich Plate ◽  
Transmission Loss ◽  
Sandwich Structures ◽  
Acoustic Medium ◽  
Element Formulation ◽  
Sound Power ◽  
Surface Mass ◽  
Various Boundary Conditions ◽  
Design Variables ◽  
Noise Transmission

An optimization methodology to increase the noise transmission loss (TL) of damped sandwich structures is presented. The prediction of the TL uses a numerical tool based on a finite element formulation for the sandwich plate coupled to a boundary element method for the acoustic medium. This tool can be used for arbitrarily shaped three-layer sandwich plates with various boundary conditions and it is well adapted to parametric and optimization studies. First, a parametric study was conducted to choose the objective function, the constraints, and the pertinent design variables to use in the optimization problem which consist in reducing the sound power transmitted by a viscoelastically damped sandwich plate. Next, by constraining the acoustical behavior of the sandwich panel, the surface mass of the sandwich structure was minimized. It is shown that a significant reduction in the transmitted sound power can be achieved by selecting the appropriate geometric configuration and damping layer material.

Numerical simulation of Lamb wave propagation in metallic foam sandwich structures: a parametric study

2013 ◽  
Vol 97 ◽  
pp. 387-400 ◽  
Author(s):  
Seyed Mohammad Hossein Hosseini ◽  
Abdolreza Kharaghani ◽  
Christoph Kirsch ◽  
Ulrich Gabbert
Keyword(s):  
Numerical Simulation ◽  
Wave Propagation ◽  
Parametric Study ◽  
Lamb Wave ◽  
Sandwich Structures ◽  
Metallic Foam ◽  
Lamb Wave Propagation

Effect of Material and Geometry on the Sound and Vibration Transmission across a Sandwich Beam

2000 ◽  
Vol 123 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Priya Thamburaj ◽  
J. Q. Sun
Keyword(s):  
Transmission Loss ◽  
Sandwich Structures ◽  
Numerical Study ◽  
Sandwich Beam ◽  
Sound Transmission ◽  
Anisotropic Materials ◽  
Sound Transmission Loss ◽  
Vibration Transmission ◽  
Isolation Performance

This paper studies sound and vibration transmission across a sandwich beam made of anisotropic materials. In our previous study, we have found that there is a significant increase in the transmission loss for the sandwich beam with anisotropic materials as compared with isotropic ones. This paper presents an extensive numerical study of the effects of damping, thickness of the laminae and density of the material on the sound transmission loss. This work may eventually lead to a new way of designing sandwich structures with high vibration and noise isolation performance.

Advances in Sandwich Structural Optimization for Noise Transmission Reduction

2006 ◽  
Author(s):  
H. Denli ◽  
Jian-Qiao Sun
Keyword(s):  
Sandwich Structures ◽  
Acoustic Radiation ◽  
Structural Parameters ◽  
Weight Ratio ◽  
Sound Transmission ◽  
Acoustic Medium ◽  
Design Parameters ◽  
Noise Transmission ◽  
Out Of Plane ◽  
Transmission Reduction

The sandwich structures in aerospace industry experience high noise transmissions since they are often stiff and light, and have low damping. Optimization studies of sandwich structures for noise transmission are relatively fewer. Most optimization studies in composite sandwich community seek for high stiffness with minimal weight. Advanced sandwiches must meet not only stiffness to weight ratio demands, but also have improved acoustic transmission performance. This paper presents recent advances in optimization of sandwich structures for minimum sound transmission. The finite element models of sandwich beams and plates are presented in this paper. The acoustic radiation of the structure is computed by using the Rayleigh integral. Sensitivity plays an important role in optimization studies. Analytical expressions of sensitivity can improve computational efficiency dramatically and accuracy at the same time. The explicit sensitivity functions of power and natural frequencies with respect to design parameters are derived in this work. In the optimization studies, we have considered structural parameters that can influence the transverse propagation of sound from the sandwich to the acoustic medium. These parameters include core topology and coupling stiffiness between in- and out-of-plane strains. We also study the optimization of the structure with respect to the structural boundary conditions to minimize the sound transmission. Numerical examples of single tone and broadband applications are presented in the paper. The results show that significant reduction of sound transmission across sandwich structures can be obtained. Finally, it should be noted that the novel optimized sandwich structures can meet not only stiffness to weight ratio demands, but also have significantly improved acoustic performance.

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