Infinite elements for wave problems: a review of current formulations and an assessment of accuracy

Astley, R.J.

doi:10.1002/1097-0207(20001110)49:7<951::aid-nme989>3.0.co;2-t

Cited by 214 publications

(125 citation statements)

References 47 publications

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“…Two approaches have been established in order to calculate acoustic exterior problems numerically: Perfectly matched layers (PML) 1 and the infinite element method (IFEM). 2,3 The method of conjugated Astley-Leis infinite elements is applied by the authors, since these elements provide the frequency-independent system matrices of stiffness, damping and mass on the basis of the corresponding FE matrices. These system matrices are required for further investigations in modal decomposition.…”

Section: Introductionmentioning

confidence: 99%

Infinite Elements and Their Influence on Normal and Radiation Modes in Exterior Acoustics

Moheit

Marburg

2017

J. Comp. Acous.

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Acoustic radiation modes (ARMs) and normal modes (NMs) are calculated at the surface of a fluid-filled domain around a solid structure and inside the domain, respectively. In order to compute the exterior acoustic problem and modes, both the finite element method (FEM) and the infinite element method (IFEM) are applied. More accurate results can be obtained by using finer meshes in the FEM or higher-order radial interpolation polynomials in the IFEM, which causes additional degrees of freedom (DOF). As such, more computational cost is required. For this reason, knowledge about convergence behavior of the modes for different mesh cases is desirable, and is the aim of this paper. It is shown that the acoustic impedance matrix for the calculation of the radiation modes can be also constructed from the system matrices of finite and infinite elements instead of boundary element matrices, as is usually done. Grouping behavior of the eigenvalues of the radiation modes can be observed. Finally, both kinds of modes in exterior acoustics are compared in the example of the cross-section of a recorder in air. When the number of DOF is increased by using higher-order radial interpolation polynomials, different eigenvalue convergences can be observed for interpolation polynomials of even and odd order.

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Section: Introductionmentioning

confidence: 99%

Infinite Elements and Their Influence on Normal and Radiation Modes in Exterior Acoustics

Moheit

Marburg

2017

J. Comp. Acous.

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“…[100][101][102][103][104][105][106][107]. This section is devoted to the presentation on the boundary element methods.…”

Section: Symmetric Boundary Element Methods Without Spurious Frequencimentioning

confidence: 99%

Advanced Computational Dissipative Structural Acoustics and Fluid-Structure Interaction in Low-and Medium-Frequency Domains. Reduced-Order Models and Uncertainty Quantification

Ohayon¹,

Soize²

2012

International Journal of Aeronautical and Space Sciences

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This paper presents an advanced computational method for the prediction of the responses in the frequency domain of general linear dissipative structural-acoustic and fluid-structure systems, in the low-and medium-frequency do mains and this includes uncertainty quantification. The system under consideration is constituted of a deformable dissipative structure that is coupled with an internal dissipative acoustic fluid. This includes wall acoustic impedances and it is surrounded by an infinite acoustic fluid. The system is submitted to given internal and external acoustic sources and to the prescribed mechanical forces. An efficient reduced-order computational model is constructed by using a finite element discretization for the structure and an internal acoustic fluid. The external acoustic fluid is treated by using an appropriate boundary element method in the frequency domain. All the required modeling aspects for the analysis of the medium-frequency domain have been introduced namely, a viscoelastic behavior for the structure, an appropriate dissipative model for the internal acoustic fluid that includes wall acoustic impedance and a model of uncertainty in particular for the modeling errors. This advanced computational formulation, corresponding to new extensions and complements with respect to the state-of-the-art are well adapted for the development of a new generation of software, in particular for parallel computers. Key words:Computational mechanics, Structural acoustics, Vibroacoustic, Fluid-structure interaction, Uncertainty quantification, Reduced-order model, Medium frequency, Low frequency, Dissipative system, Viscoelasticity, Wall acoustic impedance, Finite element discretization, Boundary element method Nomenclature a ijkh = elastic coefficients of the structure b ijkh = damping coefficients of the structure c 0 = speed of sound in the internal acoustic fluid c E = speed of sound in the external acoustic fluid f = vector of the generalized forces for the internal acoustic fluid f S = vector of the generalized forces for the structure g = mechanical body force field in the structure i = imaginary complex number i k = wave number in the external acoustic fluid n = number of internal acoustic DOF n s = number of structure DOF n j = component of vector n n = outward unit normal to Abstract This paper presents an advanced computational method for the prediction of the responses in the frequency domain of general linear dissipative structural-acoustic and uid-structure systems, in the low-and medium-frequency domains and this includes uncertainty quantication. The system under consideration is constituted of a deformable dissipative structure that is coupled with an internal dissipative acoustic uid. This includes wall acoustic impedances and it is surrounded by an innite acoustic uid. The system is submitted to given internal and external acoustic sources and to the prescribed mechanical forces. An efcient reduced-order computational model is constructed by using a nite element discret...

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“…Excellent review articles can be found in, 75 . 76 In the early formulations, only frequency-domain formulations were considered, and system matrices were developed that depended on frequency in a nonlinear manner.…”

Section: D7 Infinite Elements For Acousticsmentioning

confidence: 99%

“…As a result, time domain formulations for infinite elements were delayed for some time. The unconjugated formulations 75,77 in the time domain formulation involved convolution integrals that could be used with the frequency-dependent system matrices, but storing the time histories for the convolution integrals would be a significant burden for a time-domain code.…”

Section: D7 Infinite Elements For Acousticsmentioning

confidence: 99%

Salinas : theory manual.

Walsh¹,

Reese²,

Bhardwaj³

2011

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Salinas provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Salinas. For a more detailed description of how to use Salinas , we refer the reader to Salinas, User's Notes.Many of the constructs in Salinas are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Salinas are specific to our implementation. We try to be far more complete in those areas.The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature.3 4

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Infinite elements for wave problems: a review of current formulations and an assessment of accuracy

Cited by 214 publications

References 47 publications

Infinite Elements and Their Influence on Normal and Radiation Modes in Exterior Acoustics

Infinite Elements and Their Influence on Normal and Radiation Modes in Exterior Acoustics

Advanced Computational Dissipative Structural Acoustics and Fluid-Structure Interaction in Low-and Medium-Frequency Domains. Reduced-Order Models and Uncertainty Quantification

Salinas : theory manual.

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