Improved integro-modal approach with pressure distribution assessment and the use of overlapped cavities

Anyunzoghe, E.; Li, Cheng

doi:10.1016/s0003-682x(02)00029-4

Cited by 8 publications

(9 citation statements)

References 16 publications

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“…Spurious modes are not observed in this method. The pressure mode shapes are shown for modes [1,0] and [2,1] in Fig. 6 and are in a good agreement with the FE mode shapes except at the subcavity flexible virtual membranes due to the boundary condition, i.e.…”

Section: Regular Subcavitysupporting

confidence: 72%

“…The proposed IMCM method has less error as compared to the IMM method, for the same number of subcavities and the number of acoustic and structural modes. Figure 4 shows the pressure mode shapes of mode [1,2] and mode [2,1], respectively, for illustration. The other mode shapes are also in good agreement, however, they are not shown here for brevity.…”

Section: Regular Subcavitymentioning

confidence: 99%

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Prediction of acoustic modal characteristics of two dimensional irregular shaped cavities by impedance mobility compact matrix (IMCM) approach

Reddy¹,

Venkatesham²,

Murthy³

2020

Journal of Theoretical and Applied Mechanics

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In this paper, the impedance and mobility compact matrix (IMCM) method for prediction of acoustic modal characteristics of two-dimensional irregular cavities with the rigid wall boundary is presented. This method consists of discretizing the whole cavity into a series of subcavities either of regular or irregular shape. Continuity of both pressure and velocity between adjacent subcavities is ensured using a virtual membrane with zero mass and stiffness. Mathematical formulation for acoustic cavities with the irregular shape has been explained in detail. A finite element model has been developed to calculate the acoustic natural frequency and mode shape. The proposed method is validated using a regular and irregular cavity and compared with finite element modelling results and available results in the literature.

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Section: Regular Subcavitysupporting

confidence: 72%

Section: Regular Subcavitymentioning

confidence: 99%

Prediction of acoustic modal characteristics of two dimensional irregular shaped cavities by impedance mobility compact matrix (IMCM) approach

Reddy¹,

Venkatesham²,

Murthy³

2020

Journal of Theoretical and Applied Mechanics

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“…The frequency response of the sound pressure at (1.9 m, 0.1 m) was compared with analytical solutions based on modal superposition using 2500 modes [Anyunzoghe and Cheng, 2002] in Fig. 6.…”

Section: Validationmentioning

confidence: 99%

“…For cavities of more complex shapes, various so-called semi-analytical methods were developed [Succi, 1987;Dowell et al, 1977;Missaoui and Cheng, 1997], by pushing the analytical treatment to its limit before deploying numerical descretizations. Most of these methods, however, involve stringent limitation on the cavity shapes such as a slight distortion from a regular one [Succi, 1987], a combination of regular-shaped sub-cavities with known eigen-functions [Dowell et al, 1977] or a combination of the aforementioned scenarios [Missaoui and Cheng, 1997;Anyunzoghe and Cheng, 2002]. As a last resort, numerical solvers such as finite element methods (FEM) and boundary element method (BEM) have long been recognized as the most versatile tools to deal with systems of various shapes.…”

Section: Introductionmentioning

confidence: 99%

Shape Optimization of Acoustic Enclosures Based on a Wavelet–Galerkin Formulation

Zhang

2015

Int. J. Appl. Mechanics

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The problem of the shape optimization of acoustic enclosures is investigated in this paper. A general procedure, comprising a Wavelet–Garlerkin formulation and a so-called vertex-driven shape optimization is proposed to deal with the general problem of internal sound field prediction and the optimization of the boundary shape. It is shown that, owing to the compactly supported orthogonal property and the remarkable fitting ability, Daubechies Wavelet can be used as a global basis to approximate the unknown sound field on a relatively large interval globally instead of piecewise approximation like most of element based methods do. This feature avoids meshing the boundary of the enclosure, although vertex points are needed to define the boundary shape, whose positions keep updating during the shape optimization process. A rectangular enclosure is used as benchmark to assess and validate the proposed formulation, by investigating the influence of some key parameters involved in the formulation. It was shown that the sound pressure along the entire boundary of the rectangular enclosure can be accurately approximated without meshing. The same enclosure with an inner rigid acoustic screen is then used to reduce the sound pressure level within a chosen area through optimizing the shape of the screen, which shows the remarkable potentials of the proposed approach as a shape optimal tool for inner sound field problems.

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“…Various techniques were also developed in an attempt to increase the calculation accuracy such as the use of extended mode shape functions for a single cavity or the coupling between two overlapped adjacent sub-cavities. 10 Meanwhile, the skepticism on the modal-based method has always been persistent as evidenced by some recent papers. For example, the deficiencies of the method based on rigid-walled modes were reiterated by Ginsberg 11 , who employed an extension of Ritz series method to the problem, and the modified formulation is found to be accurate above the fundamental rigid-cavity resonance frequency for light fluid loading.…”

Section: Introductionmentioning

confidence: 99%

Convergence criteria on the acoustic velocity continuity in a panel-cavity system

Maxit

2017

The Journal of the Acoustical Society of America

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Modal-based acoustoelastic formulation is regarded as the cornerstone of vibro-acoustics and has been widely used for coupling analyses of structure-cavity systems. The controversy and the skepticism surrounding the acoustic velocity continuity with the surrounding vibrating structures have been persistent, calling for a systematic investigation and clarification. This fundamental issue of significant relevance is addressed in this paper. Through numerical analyses and comparisons with wave-based exact solution, an oscillating convergence pattern of the calculated acoustic velocity is revealed. Normalization of the results leads to a unified series truncation criterion allowing minimal prediction error, which is verified in three-dimensional cases. The paper establishes the fact that the modal based decomposition method definitely allows correct prediction of both the acoustic pressure and the velocity inside an acoustic cavity covered by a flexural structure upon using appropriate series truncation criteria.

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Improved integro-modal approach with pressure distribution assessment and the use of overlapped cavities

Cited by 8 publications

References 16 publications

Prediction of acoustic modal characteristics of two dimensional irregular shaped cavities by impedance mobility compact matrix (IMCM) approach

Prediction of acoustic modal characteristics of two dimensional irregular shaped cavities by impedance mobility compact matrix (IMCM) approach

Shape Optimization of Acoustic Enclosures Based on a Wavelet–Galerkin Formulation

Convergence criteria on the acoustic velocity continuity in a panel-cavity system

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