scholarly journals An Optimization Method for Maximizing the Low Frequency Sound Insulation of Plate Structures

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Dayi Ou
Keyword(s):  
Genetic Algorithm ◽  
Boundary Conditions ◽  
Low Frequency ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Plate Structures ◽  
Arbitrary Boundary ◽  
Frequency Sound ◽  
Arbitrary Boundary Conditions ◽  
Element Method

A combined approach based on finite element method, boundary element method, and genetic algorithm (FEM-BEM-GA) is proposed for optimizing the low frequency sound (LFS) insulation performance of plate structures. This approach can identify the optimal structural parameters (especially concerning the effects of arbitrary boundary conditions) so as to maximize the structural overall LFS insulation. The basic ideas of this approach are as follows: (1) the sound transmission loss (TL) analysis of a plate with arbitrary boundary conditions is conducted by the coupled FEM-BEM method; (2) the single-number rating method (such as low frequency sound transmission class) is used to assess the plate’s overall LFS insulation; and (3) the genetic algorithm (GA) is employed for searching the optimal solutions of the multiple-parameter optimization problem. The proposed approach is subsequently illustrated by numerical studies. The results show the effectiveness of consideration of the effects of boundary condition in the plate’s LFS insulation optimization and demonstrate the feasibility and effectiveness of this approach as a structure design tool.

Determination of the Free-Field Acoustic Radiation Characteristics of the Vibrating Plate Structures With Arbitrary Boundary Conditions

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Łukasz J. Nowak ◽  
Tomasz G. Zieliński
Keyword(s):  
Boundary Conditions ◽  
Acoustic Radiation ◽  
Free Field ◽  
Computational Time ◽  
Radiation Characteristics ◽  
Plate Structures ◽  
Arbitrary Boundary ◽  
Arbitrary Boundary Conditions ◽  
Element Method ◽  
Vibrating Plate

The paper presents the developed algorithm which implements the indirect variational boundary element method (IVBEM) for computation of the free-field acoustic radiation characteristics of vibrating rectangle-shaped plate structures with arbitrary boundary conditions. In order to significantly reduce the computational time and cost, the algorithm takes advantage of simple geometry of the considered problem and symmetries between the elements. The procedure of determining the distribution of acoustic pressure is illustrated on the example of thin, rectangular plate with a part of one edge clamped and all other edges free. The eigenfrequencies and the corresponding vibrational mode shapes of the plate are computed using the finite element method (FEM). The results of the numerical simulations are compared to the results of the experiments carried out in an anechoic chamber, proving good agreement between the predictions and the observations. The reliability of simulations and high computational efficiency make the developed algorithm a useful tool in analysis of the acoustic radiation characteristics of vibrating plate structures.

scholarly journals On the Modeling of Beam Reinforced Thin Plates Using the Spectral Element Method

2008 ◽  
Vol 15 (3-4) ◽  
pp. 425-434 ◽  
Author(s):  
N.B.F. Campos ◽  
J.R.F. Arruda
Keyword(s):  
Boundary Conditions ◽  
Spectral Element Method ◽  
Low Frequency ◽  
Element Model ◽  
Spectral Element ◽  
Computational Effort ◽  
Boundary Element Methods ◽  
Thin Plates ◽  
Arbitrary Boundary ◽  
Element Method

Modeling beam reinforced thin plates at mid and high frequencies through the most commonly used methods such as finite and boundary element methods frequently leads to unsatisfactory results, since the accuracy of these methods depends on the relation between the dimensions of the elements in which the structure was discretized and the wavelength. Due to this characteristic, the modeling using these techniques will require that the size of the elements becomes smaller as the frequency increases, while its number needs to be increased. For structures that are usual in some areas, like the aerospace industry, this will be possible only with an unreasonable computational effort, which is responsible for restricting the use of these methods practically to low-frequency applications. Semi-analytical methods such as the spectral element method do not need mesh refinement at higher frequencies, but they were very limited in the geometries and boundary conditions that can be treated. This paper presents a spectral element for rectangular thin plates reinforced symmetrically along the sides with Euler beams, which can be used to model plates with arbitrary boundary conditions. The method was verified by comparing its results with those obtained from a Finite Element model.

scholarly journals Study on broadband low-frequency sound insulation of multi-channel resonator acoustic metamaterials

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045321
Author(s):  
Chi Xu ◽  
Hui Guo ◽  
Yinghang Chen ◽  
Xiaori Dong ◽  
Hongling Ye ◽  
...  
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Acoustic Metamaterials ◽  
Frequency Sound

scholarly journals A Unified Spectro-Geometric-Ritz Method for Vibration Analysis of Open and Closed Shells with Arbitrary Boundary Conditions

2016 ◽  
Vol 2016 ◽  
pp. 1-30 ◽  
Author(s):  
Dongyan Shi ◽  
Yunke Zhao ◽  
Qingshan Wang ◽  
Xiaoyan Teng ◽  
Fuzhen Pang
Keyword(s):  
Boundary Conditions ◽  
Vibration Analysis ◽  
Ritz Method ◽  
Free Vibration Analysis ◽  
Analysis Model ◽  
Arbitrary Boundary ◽  
Fourier Cosine ◽  
Auxiliary Functions ◽  
Arbitrary Boundary Conditions ◽  
Closed Shells

This paper presents free vibration analysis of open and closed shells with arbitrary boundary conditions using a spectro-geometric-Ritz method. In this method, regardless of the boundary conditions, each of the displacement components of open and closed shells is represented simultaneously as a standard Fourier cosine series and several auxiliary functions. The auxiliary functions are introduced to accelerate the convergence of the series expansion and eliminate all the relevant discontinuities with the displacement and its derivatives at the boundaries. The boundary conditions are modeled using the spring stiffness technique. All the expansion coefficients are treated equally and independently as the generalized coordinates and determined using Rayleigh-Ritz method. By using this method, a unified vibration analysis model for the open and closed shells with arbitrary boundary conditions can be established without the need of changing either the equations of motion or the expression of the displacement components. The reliability and accuracy of the proposed method are validated with the FEM results and those from the literature.

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