Journal articles: 'Acoustic finite element model'

1

Shi, Wen Ku, Guang Ming Wu, Zhi Yong Chen, and Nian Cheng Guo. "Prediction and Analysis of Vehicle Cab Interior Noise Based on Structure-Acoustic Coupling." Advanced Materials Research 424-425 (January 2012): 637–40. http://dx.doi.org/10.4028/www.scientific.net/amr.424-425.637.

Full text

Abstract:

To study the vibration characteristics of the vehicle’s cab, finite element model of the cab was established and structural modal analysis was made. According to the internal structure of the cab, acoustic finite element modal of the cab including the seats was built and cavity acoustics modal analysis was carried out. Based on the structural modal and acoustic model of the cab, the coupled acoustic-structure model was carried. The acoustic response of the cab was calculated by mode-superposition

APA, Harvard, Vancouver, ISO, and other styles

2

Wu, S. W., S. H. Lian, and L. H. Hsu. "A FINITE ELEMENT MODEL FOR ACOUSTIC RADIATION." Journal of Sound and Vibration 215, no. 3 (August 1998): 489–98. http://dx.doi.org/10.1006/jsvi.1998.1664.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

MAR-OR, ASSAF, and DAN GIVOLI. "A FINITE ELEMENT STRUCTURAL-ACOUSTIC MODEL OF COUPLED MEMBRANES." Journal of Computational Acoustics 12, no. 04 (December 2004): 605–18. http://dx.doi.org/10.1142/s0218396x04002407.

Full text

Abstract:

A simple model displaying structural-acoustic behavior is considered. The model comprises of two parallel infinitely-long flat membranes lying on elastic foundations and the acoustic medium separating them. The structural-acoustic coupling manifests itself in that a vibrational excitation of one of the membranes triggers vibrations in the other. The governing equations are stated, and the associated finite element formulation is constructed. The model is then analyzed numerically and its vibrational properties are investigated. The proposed model is especially simple, being two-dimensional and involving a small number of parameters, but at the same time it brings to light some important features associated with structural-acoustic coupling. Therefore it may serve as a benchmark for evaluating structural-acoustic numerical schemes and as an educational tool for studying structural-acoustic coupling in a simple context.

APA, Harvard, Vancouver, ISO, and other styles

4

Wan, Zhimin, Ting Wang, Qibai Huang, and Jianliang Wang. "Acoustic finite element model updating using acoustic frequency response function." Finite Elements in Analysis and Design 87 (September 2014): 1–9. http://dx.doi.org/10.1016/j.finel.2014.04.007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

LISTERUD, EIVIND, and WALTER EVERSMAN. "FINITE ELEMENT MODELING OF ACOUSTICS USING HIGHER ORDER ELEMENTS PART II: TURBOFAN ACOUSTIC RADIATION." Journal of Computational Acoustics 12, no. 03 (September 2004): 431–46. http://dx.doi.org/10.1142/s0218396x04002353.

Full text

Abstract:

A study is made of computational accuracy and efficiency for finite element modeling of acoustic radiation in a nonuniform moving medium. For a given level of accuracy for acoustic pressure, cubic serendipity elements are shown to require a less dense mesh than quadratic elements. These elements have been applied to the near field of inlet and aft acoustic radiation models for a turbofan engine and they yield considerable reduction in the dimensionality of the problem without sacrificing accuracy. The results show that for computation of acoustic pressure the cubic element formulation model is superior to the quadratic. Performance gains in computation of acoustic potential are not as significant. In the external radiated field, improved convergence using cubic serendipity elements is shown by comparison of contours of constant pressure magnitude.

APA, Harvard, Vancouver, ISO, and other styles

6

Murphy, Joseph E., and Stanley A. Chin-Bing. "A finite element model for ocean acoustic propagation." Mathematical and Computer Modelling 11 (1988): 70–74. http://dx.doi.org/10.1016/0895-7177(88)90457-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

LISTERUD, EIVIND, and WALTER EVERSMAN. "FINITE ELEMENT MODELING OF ACOUSTICS USING HIGHER ORDER ELEMENTS PART I: NONUNIFORM DUCT PROPAGATION." Journal of Computational Acoustics 12, no. 03 (September 2004): 397–429. http://dx.doi.org/10.1142/s0218396x0400233x.

Full text

Abstract:

Cubic serendipity elements have been implemented into a nonuniform duct model of acoustic propagation in a moving medium. This model uses a convective potential formulation derived from the inviscid linearized mass and momentum equations. The model requires post-processing to calculate acoustic pressure. These elements outperform the quadratic serendipity elements in terms of computational efficiency based on visual observations and error norm analysis of acoustic pressure. CPU time reduction of up to 40% has been observed without sacrificing accuracy. Any penalty in numerical accuracy incurred by using serendipity elements rather than Lagrangian elements is far outweighed by the gains in dimensionality. The computational gains for calculation of acoustic potential are considerably less. Analytical expressions for the modal and convective effects on the propagating wavelength have been formulated and compared to numerical results. Preliminary assessment of alternative finite element approaches to model the convective potential formulation has been conducted. Stabilization and wave approximation methods have been implemented to solve simple one-dimensional problems.

APA, Harvard, Vancouver, ISO, and other styles

8

Hou, Wei Ling, Hong Zhou, and Si Le Wang. "Acoustic Modal Test and Finite Element Analysis on Vehicle Cavity." Applied Mechanics and Materials 239-240 (December 2012): 32–36. http://dx.doi.org/10.4028/www.scientific.net/amm.239-240.32.

Full text

Abstract:

A cavity acoustic modal of a medium-sized commercial vehicle was tested and analyzed based on LMS Test.Lab modal analysis system. Acoustic modal characteristics, including modal frequencies and modal shapes of the cavity, were obtained. By comparing the results of acoustic modal frequencies to the structure modal ones, the acoustic-structure coupling at critical frequencies could be avoided and the noise in low frequency range could be reduced. Meanwhile, the simulation of the acoustic modal is analyzed by establishing the finite element model of the cavity, which may be a reference to improve the interior acoustic properties of the cavity.

APA, Harvard, Vancouver, ISO, and other styles

9

Danda Roy, I., and W. Eversman. "Improved Finite Element Modeling of the Turbofan Engine Inlet Radiation Problem." Journal of Vibration and Acoustics 117, no. 1 (January 1, 1995): 109–15. http://dx.doi.org/10.1115/1.2873853.

Full text

Abstract:

Improvements have been made in the finite element model of the acoustic radiated field from a turbofan engine inlet in the presence of a mean flow. The problem of acoustic radiation from a turbofan engine inlet is difficult to model numerically because of the large domain and high frequencies involved. A numerical model with conventional finite elements in the near field and wave envelope elements in the far field has been constructed. By employing an irrotational mean flow assumption, both the mean flow and the acoustic perturbation problem have been posed in an axisymmetric formulation in terms of the velocity potential, thereby minimizing computer storage and time requirements. The finite element mesh has been altered in search of an improved solution. The mean flow problem has been reformulated with new boundary conditions to make it theoretically rigorous. The sound source at the fan face has been modeled as a combination of positive and negative propagating duct eigenfunctions. Therefore, a finite element duct eigenvalue problem has been solved on the fan face and the resulting modal matrix has been used to implement a source boundary condition on the fan face in the acoustic radiation problem. In the post processing of the solution, the acoustic pressure has been evaluated at Gauss points inside the elements and the nodal pressure values have been interpolated from them. This has significantly improved the results. The effect of the geometric position of the transition circle between conventional finite elements and wave envelope elements has been studied and it has been found that the transition can be made nearer to the inlet than previously assumed.

APA, Harvard, Vancouver, ISO, and other styles

10

Kaselouris, Evaggelos, Chrysoula Alexandraki, Yannis Orphanos, Makis Bakarezos, Michael Tatarakis, Nektarios A. Papadogiannis, and Vasilis Dimitriou. "Acoustic analysis of impact sound on vibrating circular membranes." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 3 (August 1, 2021): 3378–85. http://dx.doi.org/10.3397/in-2021-2389.

Full text

Abstract:

A finite element method (FEM) - boundary element method (BEM) model is developed to compute the sound generated by of a force acting on a circular membrane (drumhead). A vibro-acoustic analysis that combines modal FEM analysis, a FEM steady state dynamic analysis (SSD), considering harmonic loading and boundary element acoustics, is performed. The drumhead vibrates due to the force impact and the sound is emitted in the air. The vibration of structural response is initially computed, and the obtained results are set to be the boundary conditions of the acoustic analysis in the vibro-acoustic simulation. The radiated sound can be computed at any point of the solution domain. Various materials used by drumhead manufacturers are tested and a parametric analysis focusing on the mesh density of the models is presented. The impact sound and the acoustical characteristics of the simulated test cases are evaluated. The Rayleigh method is also applied to the acoustic simulations and is further compared to the BEM simulation results. The outcomes of this study may be further used as reverse engineering inputs, to machine learning models for the estimation of the physical and mechanical parameters of drumheads from audio signals.

APA, Harvard, Vancouver, ISO, and other styles

11

Gunderson, Aaron. "3D finite element modeling techniques and application to underwater target scattering." Journal of the Acoustical Society of America 151, no. 4 (April 2022): A54. http://dx.doi.org/10.1121/10.0010637.

Full text

Abstract:

Underwater acoustic target scattering measurements rely on high-fidelity modeling for experimental comparison and understanding. Three-dimensional (3D) finite element models are well suited for this purpose, as they can account for arbitrary or unknown target properties and configurations/orientations within complex and asymmetrical seafloor environments. High acoustic frequencies and large physical distances associated with in situ scattering measurements pose challenges to 3D modeling efforts in terms of model sizes and runtimes. Certain model considerations must be made to keep the 3D model computationally efficient, yet accurate in predictive capability. Numerically determined Green’s functions are demonstrated to permit 3D model reduction, while still preserving far-field scattering prediction capability through the Helmholtz–Kirchhoff integral. By determining Green’s functions within the model, they need not be known or estimated for complex ocean environments a priori. Nontraditional scattering formulations and a survey of boundary truncation methods also are explored and implemented for maximal accuracy within small 3D computational domains. Model results for canonical elastic targets within varying seafloor environments are shown and compared to theory and experimentation. [Work supported by the Strategic Environmental Research and Development Program and by the Office of Naval Research, Ocean Acoustics.]

APA, Harvard, Vancouver, ISO, and other styles

12

Yu, Kok Hwa. "ACOUSTIC EFFECTS ON BINARY AEROELASTICITY MODEL." IIUM Engineering Journal 12, no. 2 (October 18, 2011): 123–30. http://dx.doi.org/10.31436/iiumej.v12i2.108.

Full text

Abstract:

Acoustics is the science concerned with the study of sound. The effects of sound on structures attract overwhelm interests and numerous studies were carried out in this particular area. Many of the preliminary investigations show that acoustic pressure produces significant influences on structures such as thin plate, membrane and also high-impedance medium like water (and other similar fluids). Thus, it is useful to investigate the structure response with the presence of acoustics on aircraft, especially on aircraft wings, tails and control surfaces which are vulnerable to flutter phenomena. The present paper describes the modeling of structural-acoustic interactions to simulate the external acoustic effect on binary flutter model. Here, the binary flutter model which illustrated as a rectangular wing is constructed using strip theory with simplified unsteady aerodynamics involving flap and pitch degree of freedom terms. The external acoustic excitation, on the other hand, is modeled using four-node quadrilateral isoparametric element via finite element approach. Both equations then carefully coupled and solved using eigenvalue solution. The mentioned approach is implemented in MATLAB and the outcome of the simulated result are later described, analyzed and illustrated in this paper.

APA, Harvard, Vancouver, ISO, and other styles

13

Abbasi, Mustafa Z., Preston S. Wilson, and Ofodike A. Ezekoye. "Ray tracing and finite element modeling of sound propagation in a compartment fire." Journal of the Acoustical Society of America 151, no. 5 (May 2022): 3177–88. http://dx.doi.org/10.1121/10.0009800.

Full text

Abstract:

A compartment fire (a fire in a room or building) creates temperature gradients and inhomogeneous time-varying temperature, density, and flow fields. This work compared experimental measurements of the room acoustic impulse/frequency response in a room with a fire to numerically modeled responses. The fire is modeled using a Fire Dynamics Simulator (FDS). Acoustic modeling was performed using the temperature field computed by FDS. Room acoustics were modeled using two-dimensional ray and finite element modeling. A three-dimensional model was used to simulate an open flame. COMSOLTM Multiphysics was used for finite element acoustic modeling and BELLHOPTM for ray trace acoustics modeling. The results show that the fire causes wave-fronts to arrive earlier (due to the higher sound speed) and with more variation in the delay times (due to the sound speed perturbations). The resonance frequencies of low-frequency modes were shifted upwards. Model results are compared with data and show good agreement in observed trends.

APA, Harvard, Vancouver, ISO, and other styles

14

Liang, Yan De, Hong Ling, and Yuan Zhang. "Study on the Conditions of Near-Field Acoustic Levitation." Advanced Materials Research 97-101 (March 2010): 4135–40. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.4135.

Full text

Abstract:

This paper establishes a near-field acoustic radiation pressure solving model applying with acoustics theory and derives an initial acoustic levitation calculating formula of rotundity objects. Combining with finite element and boundary element analysis, levitate conditions of levitated objects are calculated. This paper takes rectangular ultrasonic oscillator for example, testing and analyzing conditions of near-field acoustic levitation by using self-designed test equipments, the results are proved to be better.

APA, Harvard, Vancouver, ISO, and other styles

15

Tian, Wanyi, Lingyun Yao, and Li Li. "A Coupled Smoothed Finite Element-Boundary Element Method for Structural-Acoustic Analysis of Shell." Archives of Acoustics 42, no. 1 (March 1, 2017): 49–59. http://dx.doi.org/10.1515/aoa-2017-0006.

Full text

Abstract:

Abstract Nowadays, the finite element method (FEM) - boundary element method (BEM) is used to predict the performance of structural-acoustic problem, i.e. the frequency response analysis, modal analysis. The accuracy of conventional FEM/BEM for structural-acoustic problems strongly depends on the size of the mesh, element quality, etc. As element size gets greater and distortion gets severer, the deviation of high frequency problem is also clear. In order to improve the accuracy of structural-acoustic problem, a smoothed finite-element/boundary-element coupling procedure (SFEM/BEM) is extended to analyze the structural-acoustic problem consisting of a shell structure interacting with the cavity in this paper, in which the SFEM and boundary element method (BEM) models are used to simulate the structure and the fluid, respectively. The governing equations of the structural-acoustic problems are established by coupling the SFEM for the structure and the BEM for the fluid. The solutions of SFEM are often found to be much more accurate than those of the FEM model. Based on its attractive features, it was decided in the present work to extend SFEM further for use in structural-acoustic analysis by coupling it with BEM, the present SFEM/BEM is implemented to predict the vehicle structure-acoustic frequency response analysis, and two numerical experiments results show that the present method can provide more accurate results compared with the standard FEM/BEM using the same mesh. It indicates that the present SFEM/BEM can be widely applied to solving many engineering noise, vibration and harshness (NVH) problems with more accurate solutions.

APA, Harvard, Vancouver, ISO, and other styles

16

Henríquez, V. Cutanda, P. Risby Andersen, J. Søndergaard Jensen, P. Møller Juhl, and J. Sánchez-Dehesa. "A Numerical Model of an Acoustic Metamaterial Using the Boundary Element Method Including Viscous and Thermal Losses." Journal of Computational Acoustics 25, no. 04 (November 21, 2017): 1750006. http://dx.doi.org/10.1142/s0218396x17500060.

Full text

Abstract:

In recent years, boundary element method (BEM) and finite element method (FEM) implementations of acoustics in fluids with viscous and thermal losses have been developed. They are based on the linearized Navier–Stokes equations with no flow. In this paper, such models with acoustic losses are applied to an acoustic metamaterial. Metamaterials are structures formed by smaller, usually periodic, units showing remarkable physical properties when observed as a whole. Acoustic losses are relevant in metamaterials in the millimeter scale. In addition, their geometry is intricate and challenging for numerical implementation. The results are compared with existing measurements.

APA, Harvard, Vancouver, ISO, and other styles

17

Harari, Isaac, and Danny Avraham. "High-Order Finite Element Methods for Acoustic Problems." Journal of Computational Acoustics 05, no. 01 (March 1997): 33–51. http://dx.doi.org/10.1142/s0218396x97000046.

Full text

Abstract:

The goal of this work is to design and analyze quadratic finite elements for problems of time-harmonic acoustics, and to compare the computational efficiency of quadratic elements to that of lower-order elements. Non-reflecting boundary conditions yield an equivalent problem in a bounded region which is suitable for domain-based computation of solutions to exterior problems. Galerkin/least-squares technology is utilized to develop robust methods in which stability properties are enhanced while maintaining higher-order accuracy. The design of Galerkin/least-squares methods depends on the order of interpolation employed, and in this case quadratic elements are designed to yield dispersion-free solutions to model problems. The accuracy of Galerkin/least-squares and traditional Galerkin elements is compared, as well as the accuracy of quadratic versus standard linear interpolation, incorporating the effects of representing the radiation condition in exterior problems. The efficiency of the various methods is measured in terms of the cost of computation, rather than resolution requirements. In this manner, clear guidelines for selecting the order of interpolation are derived. Numerical testing validates the superior performance of the proposed methods. This work is a first step to gaining a thorough analytical understanding of the performance of p refinement as a basis for the development of h-p finite element methods for large-scale computation of solutions to acoustic problems.

APA, Harvard, Vancouver, ISO, and other styles

18

Sathyan, Sabin, Ugur Aydin, and Anouar Belahcen. "Acoustic Noise Computation of Electrical Motors Using the Boundary Element Method." Energies 13, no. 1 (January 3, 2020): 245. http://dx.doi.org/10.3390/en13010245.

Full text

Abstract:

This paper presents a numerical method and computational results for acoustic noise of electromagnetic origin generated by an induction motor. The computation of noise incorporates three levels of numerical calculation steps, combining both the finite element method and boundary element method. The role of magnetic forces in the production of acoustic noise is established in the paper by showing the magneto-mechanical and vibro-acoustic pathway of energy. The conversion of electrical energy into acoustic energy in an electrical motor through electromagnetic, mechanical, or acoustic platforms is illustrated through numerical computations of magnetic forces, mechanical deformation, and acoustic noise. The magnetic forces were computed through 2D electromagnetic finite element simulation, and the deformation of the stator due to these forces was calculated using 3D structural finite element simulation. Finally, boundary element-based computation was employed to calculate the sound pressure and sound power level in decibels. The use of the boundary element method instead of the finite element method in acoustic computation reduces the computational cost because, unlike finite element analysis, the boundary element approach does not require heavy meshing to model the air surrounding the motor.

APA, Harvard, Vancouver, ISO, and other styles

19

Everstine, Gordon C., Guillermo C. Gaunaurd, and Hanson Huang. "Acoustic Scattering by Two Submerged Spherical Shells." Journal of Computational Acoustics 06, no. 04 (December 1998): 421–34. http://dx.doi.org/10.1142/s0218396x98000272.

Full text

Abstract:

We validate, using a coupled finite element/boundary element computer code, a recently-developed1 series solution for the structural acoustics problem of scattering from two submerged spherical elastic shells. Although the general purpose computational tools for acoustic scattering have never been restricted to single scatterers, the availability of the series solution provides, for the first time, the mutual validation of both exact and numerical approaches for a multiple elastic scatterer problem. The excellent agreement between the two solutions presented thus allows this problem to be added to the short list of existing benchmark structural acoustics problems possessing an analytic solution. For the purposes of this comparison, the direction of incidence is taken as parallel with the axis joining the two shells. The numerical solution uses the NASHUA code, which couples a finite element shell model of the two shells with a boundary element model of the surrounding fluid. The exact solution is found by expanding in terms of classical modal series and uses the addition theorem for the spherical wave functions. The exact solution requires coupling coefficients that are expressed in terms of sums of products of Wigner 3-j symbols (or Clebsch-Gordan coefficients).

APA, Harvard, Vancouver, ISO, and other styles

20

Abdullahi, Mustapha, and S. Oyadiji. "Acoustic Wave Propagation in Air-Filled Pipes Using Finite Element Analysis." Applied Sciences 8, no. 8 (August 7, 2018): 1318. http://dx.doi.org/10.3390/app8081318.

Full text

Abstract:

The major objective of this work is to develop an efficient Finite Element Analysis (FEA) procedure to simulate wave propagation in air-filled pipes accurately. The development of such a simulation technique is essential in the study of wave propagation in pipe networks such as oil and gas pipelines and urban water distribution networks. While numerical analysis using FEA seems superficially straight forward, this paper demonstrates that the element type and refinement used for acoustic FEA have a significant effect on the accuracy of the result achieved and the efficiency of the computation. In particular, it is shown that the well-known, better overall performance achieved with 3D solid hexahedral elements in comparison with 2D-type elements in most stress and thermal applications does not occur with acoustic analysis. In this paper, FEA models were developed taking into account the influence of element type and sizes using 2D-like and 3D element formulations, as well as linear and quadratic nodal interpolations. Different mesh sizes, ranging from large to very small acoustic wavelengths, were considered. The simulation scheme was verified using the Time of Flight approach to derive the predicted acoustic wave velocity which was compared with the true acoustic wave velocity, based on the input bulk modulus and density of air. For finite element sizes of the same order as acoustic wavelengths which correspond to acoustic frequencies between 1 kHz and 1 MHz, the errors associated with the predictions based on the 3D solid hexahedral acoustic elements were mostly greater than 15%. However, for the same element sizes, the errors associated with the predictions based on the 2D-like axisymmetric solid acoustic elements were mostly less than 2%. This indicates that the 2D-like axisymmetric solid acoustic elements are much more efficient than the 3D hexahedral acoustic elements in predicting acoustic wave propagation in air-filled pipes, as they give higher accuracies and are less computationally intensive. In most stress and thermal FEA, the 3D solid hexahedral elements are much more efficient than 2D-type elements. However, for acoustic FEA, the results show that 2D-like axisymmetric elements are much more efficient than 3D solid hexahedral elements.

APA, Harvard, Vancouver, ISO, and other styles

21

Murphy, Joseph E., and Stanley A. Chin‐Bing. "A finite‐element model for ocean acoustic propagation and scattering." Journal of the Acoustical Society of America 86, no. 4 (October 1989): 1478–83. http://dx.doi.org/10.1121/1.398708.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Fan, S. C., S. M. Li, and G. Y. Yu. "Dynamic Fluid-Structure Interaction Analysis Using Boundary Finite Element Method–Finite Element Method." Journal of Applied Mechanics 72, no. 4 (August 20, 2004): 591–98. http://dx.doi.org/10.1115/1.1940664.

Full text

Abstract:

In this paper, the boundary finite element method (BFEM) is applied to dynamic fluid-structure interaction problems. The BFEM is employed to model the infinite fluid medium, while the structure is modeled by the finite element method (FEM). The relationship between the fluid pressure and the fluid velocity corresponding to the scattered wave is derived from the acoustic modeling. The BFEM is suitable for both finite and infinite domains, and it has advantages over other numerical methods. The resulting system of equations is symmetric and has no singularity problems. Two numerical examples are presented to validate the accuracy and efficiency of BFEM-FEM coupling for fluid-structure interaction problems.

APA, Harvard, Vancouver, ISO, and other styles

23

Farahikia, Mahdi, and Ronald N. Miles. "Development of boundary element method to analyze acoustic models with comparison to finite element model." Journal of the Acoustical Society of America 137, no. 4 (April 2015): 2290. http://dx.doi.org/10.1121/1.4920360.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Wu, Y., X. Y. Lin, H. X. Jiang, and A. G. Cheng. "Finite Element Analysis of the Uncertainty of Physical Response of Acoustic Metamaterials with Interval Parameters." International Journal of Computational Methods 17, no. 08 (July 19, 2019): 1950052. http://dx.doi.org/10.1142/s021987621950052x.

Full text

Abstract:

The physical response of acoustic metamaterials may change due to the variation of the material properties in the manufacture process. Thus, an interval perturbation finite element method is formulated to study the mechanical response of acoustic metamaterials with the interval parameters, which includes the uncertainty effects on the band structure, resonance mode and frequency response of acoustic metamaterials. By virtue of the first-order Taylor series expansion and sensitivity analysis of dynamic properties of acoustic metamaterials with respect to the interval parameters, the interval perturbation finite element method established in this work can predict the upper and lower bounds of the dynamic properties of the acoustic metamaterials. Three numerical examples are studied to validate the effectiveness of the interval perturbation finite element method to analyze the physical response of acoustic metamaterials with the interval parameters, and the results calculated by Monte Carlo method are regarded as the reference results to validate the interval perturbation finite element method. The uncertainty model constructed by interval perturbation finite element method provides a great help in the design of acoustic metamaterials.

APA, Harvard, Vancouver, ISO, and other styles

25

Xu, Yi Feng, and Jun Wang. "Modal Parameter Validation in Coupled Vibro-Acoustical System." Advanced Materials Research 301-303 (July 2011): 629–34. http://dx.doi.org/10.4028/www.scientific.net/amr.301-303.629.

Full text

Abstract:

The aim of this paper is to validate the modal parameters used in coupled structural finite element and acoustic boundary element algorithm to analysis the structure subjected to diffuse acoustic field. The theoretical deduction of non-symmetric coupled vibro-acoustical modal analysis was introduced firstly. In order to verify the modal truncation frequency how to affect the simulation results, based on the reciprocity theorem used in coupled FE-BE model, three different truncation frequency conditions were performed. The contrastive results show that twice the upper calculation frequency as the truncated modal frequency can make the simulation effectively and efficiently.

APA, Harvard, Vancouver, ISO, and other styles

26

Tsoi, Ben, Bryce Gardner, and Vincent Cotoni. "Experimental validation of finite element–boundary element model dynamic strain model under diffuse acoustic field loading." Journal of the Acoustical Society of America 127, no. 3 (March 2010): 1770. http://dx.doi.org/10.1121/1.3383829.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Yao, Lingyun, Wanyi Tian, and Fei Wu. "An Optimized Generalized Integration Rules for Error Reduction of Acoustic Finite Element Model." International Journal of Computational Methods 15, no. 07 (October 12, 2018): 1850062. http://dx.doi.org/10.1142/s0219876218500627.

Full text

Abstract:

In the finite element method (FEM), the accuracy in acoustic problems will deteriorate with the increasing frequency due to the “dispersion effect”. In order to minimize discretization error, a novel optimized generalized integration rules (OGIR) is introduced into FEM for the reduction of discretization error. In the present work, the adaptive genetic algorithm (AGA) is implemented to sight the optimized location of integration points. Firstly, the generalized integration rules (GIR) is used to parameterize the Gauss point location, then the relationship between the location parameterize of the integration points and discretization error is derived in detail, and the optimized location of the integration points is found through the optimization procedure, and then the OGIR–FEM is finally proposed to solve the acoustic problem. It also can be directly used to solve the optional acoustic problem, including the damped problems. Numerical example involving distorted meshes indicates that present OGIR–FEM has a superior error reducing performance in comparison with the other error reducing finite elements. These researches indicate that the proposed method can be more widely applied to solving practical acoustic problems with more accurate solutions.

APA, Harvard, Vancouver, ISO, and other styles

28

Kung, Chaw-Hua, and Rajendra Singh. "Finite Element Modeling of Annular-Like Acoustic Cavities." Journal of Vibration and Acoustics 107, no. 1 (January 1, 1985): 81–85. http://dx.doi.org/10.1115/1.3274720.

Full text

Abstract:

A finite element technique has been developed to find natural frequencies and modes of undamped three-dimensional acoustic cavities. This method utilizes the analogy between a special form of the discretized transient heat conduction equations and discretized equations of acoustic pressure oscillation. The proposed technique is verified by applying it to several cavities of known theoretical eigen-solutions. Computed results for an acoustic ring, an acoustic disk, and a pure annular cavity match extremely well with exact solutions. In addition, the condensation scheme is investigated and guidelines of selecting acoustic master nodes appropriately are also discussed in the paper. Using the validated finite element method along with suitable condensation, the eigenvalue problem of an annular-like cavity is solved. Since the exact solution for this case is not possible, finite element computations for natural frequencies and modes are compared with the measured results obtained using an acoustic modal analysis experimental technique; again very good agreement has been found.

APA, Harvard, Vancouver, ISO, and other styles

29

Ni, Guangjian, Stephen J. Elliott, and Johannes Baumgart. "Finite-element model of the active organ of Corti." Journal of The Royal Society Interface 13, no. 115 (February 2016): 20150913. http://dx.doi.org/10.1098/rsif.2015.0913.

Full text

Abstract:

The cochlear amplifier that provides our hearing with its extraordinary sensitivity and selectivity is thought to be the result of an active biomechanical process within the sensory auditory organ, the organ of Corti. Although imaging techniques are developing rapidly, it is not currently possible, in a fully active cochlea, to obtain detailed measurements of the motion of individual elements within a cross section of the organ of Corti. This motion is predicted using a two-dimensional finite-element model. The various solid components are modelled using elastic elements, the outer hair cells (OHCs) as piezoelectric elements and the perilymph and endolymph as viscous and nearly incompressible fluid elements. The model is validated by comparison with existing measurements of the motions within the passive organ of Corti, calculated when it is driven either acoustically, by the fluid pressure or electrically, by excitation of the OHCs. The transverse basilar membrane (BM) motion and the shearing motion between the tectorial membrane and the reticular lamina are calculated for these two excitation modes. The fully active response of the BM to acoustic excitation is predicted using a linear superposition of the calculated responses and an assumed frequency response for the OHC feedback.

APA, Harvard, Vancouver, ISO, and other styles

30

SHEU, TONY W. H., and C. C. FANG. "A HIGH RESOLUTION FINITE ELEMENT ANALYSIS FOR NONLINEAR ACOUSTIC WAVE PROPAGATION." Journal of Computational Acoustics 02, no. 01 (March 1994): 29–51. http://dx.doi.org/10.1142/s0218396x9400004x.

Full text

Abstract:

We investigate the application of Taylor Galerkin finite element model to simulate the propagation of impulse disturbances governed by the nonlinear Euler equations. This formulation is based on the conservation variables rather than the primitive variables so that the slowly emerging sharp acoustic profiles due to the initial fluctuation can be sharply captured. We show that when the generalized Taylor Galerkin finite element model is combined with the flux corrected transport technique of Boris and Book, the acoustic field can be more accurately predicted. The proposed prediction method was validated first by simulating different classes of transport profiles before applying it to investigate the truly nonlinear acoustic field emanating from an initial square pulse.

APA, Harvard, Vancouver, ISO, and other styles

31

Assaf, Samir, and Jean-Marie Lagache. "Modal finite element synthesis of acoustic boundary receptances." Mécanique & Industries 9, no. 6 (November 2008): 579–88. http://dx.doi.org/10.1051/meca/2009022.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Simon, Andrade, Desmulliez, Riehle, and Bernassau. "Numerical Determination of the Secondary Acoustic Radiation Force on a Small Sphere in a Plane Standing Wave Field." Micromachines 10, no. 7 (June 29, 2019): 431. http://dx.doi.org/10.3390/mi10070431.

Full text

Abstract:

Two numerical methods based on the Finite Element Method are presented for calculating the secondary acoustic radiation force between interacting spherical particles. The first model only considers the acoustic waves scattering off a single particle, while the second model includes re-scattering effects between the two interacting spheres. The 2D axisymmetric simplified model combines the Gor’kov potential approach with acoustic simulations to find the interacting forces between two small compressible spheres in an inviscid fluid. The second model is based on 3D simulations of the acoustic field and uses the tensor integral method for direct calculation of the force. The results obtained by both models are compared with analytical equations, showing good agreement between them. The 2D and 3D models take, respectively, seconds and tens of seconds to achieve a convergence error of less than 1%. In comparison with previous models, the numerical methods presented herein can be easily implemented in commercial Finite Element software packages, where surface integrals are available, making it a suitable tool for investigating interparticle forces in acoustic manipulation devices.

APA, Harvard, Vancouver, ISO, and other styles

33

SANTOS, JUAN ENRIQUE, JIM DOUGLAS, MARY E. MORLEY, and OSCAR M. LOVERA. "Finite Element Methods for a Model for Full Waveform Acoustic Logging." IMA Journal of Numerical Analysis 8, no. 4 (1988): 415–33. http://dx.doi.org/10.1093/imanum/8.4.415.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

De Rosa, Sergio, Francesco Franco, Mauro Fontana, Romualdo Paino, and Antonio Sollo. "The structural acoustic optimization of an unstiffened cylinder finite‐element model." Journal of the Acoustical Society of America 105, no. 2 (February 1999): 1087. http://dx.doi.org/10.1121/1.425095.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Phadnis, V. A., A. Roy, and V. V. Silberschmidt. "Ultrasonically assisted drilling: A finite-element model incorporating acoustic softening effects." Journal of Physics: Conference Series 451 (July 17, 2013): 012040. http://dx.doi.org/10.1088/1742-6596/451/1/012040.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Isakson, Marcia. "A finite element model for acoustic propagation in shallow water waveguides." Journal of the Acoustical Society of America 125, no. 4 (April 2009): 2501. http://dx.doi.org/10.1121/1.4783378.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Brennan, Brian, and Robert C. Kirby. "Finite element approximation and preconditioners for a coupled thermal–acoustic model." Computers & Mathematics with Applications 70, no. 10 (November 2015): 2342–54. http://dx.doi.org/10.1016/j.camwa.2015.09.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Alimonti, Luca, Abderrazak Mejdi, and Andrea Parrinello. "SEA model for structural acoustic coupling by means of periodic finite element models of the structural subsystems." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 1 (August 1, 2021): 5301–9. http://dx.doi.org/10.3397/in-2021-3044.

Full text

Abstract:

Statistical Energy Analysis (SEA) often relies on simplified analytical models to compute the parameters required to build the power balance equations of a coupled vibro-acoustic system. However, the vibro-acoustic of modern structural components, such as thick sandwich composites, ribbed panels, isogrids and metamaterials, is often too complex to be amenable to analytical developments without introducing further approximations. To overcome this limitation, a more general numerical approach is considered. It was shown in previous publications that, under the assumption that the structure is made of repetitions of a representative unit cell, a detailed Finite Element (FE) model of the unit cell can be used within a general and accurate numerical SEA framework. In this work, such framework is extended to account for structural-acoustic coupling. Resonant as well as non-resonant acoustic and structural paths are formulated. The effect of any acoustic treatment applied to coupling areas is considered by means of a Generalized Transfer Matrix (TM) approach. Moreover, the formulation employs a definition of pressure loads based on the wavenumber-frequency spectrum, hence allowing for general sources to be fully represented without simplifications. Validations cases are presented to show the effectiveness and generality of the approach.

APA, Harvard, Vancouver, ISO, and other styles

39

Essahbi, Soufien, Emmanuel Perry‐Debain, Mohamed Haddar, Lotfi Hammami, and Mabrouk Ben Tahar. "On the use of the plane wave based method for vibro‐acoustic problems." Multidiscipline Modeling in Materials and Structures 7, no. 4 (November 15, 2011): 356–69. http://dx.doi.org/10.1108/15736101111185261.

Full text

Abstract:

PurposeThe purpose of this paper is to present the extension of plane wave based method.Design/methodology/approachThe mixed functional are discretized using enriched finite elements. The fluid is discretized by enriched acoustic element, the structure by enriched structural finite element and the interface fluid‐structure by fluid‐structure interaction element.FindingsResults obtained show the potentialities of the proposed method to solve a much larger class of wave problems in mid‐ and high‐frequency ranges.Originality/valueThe plane wave based method has previously been applied successfully to finite element and boundary element models for the Helmholtz equation and elastodynamic problems. This paper describes the extension of this method to the vibro‐acoustic problem.

APA, Harvard, Vancouver, ISO, and other styles

40

Ai, Yan Ting, Song Jin Li, Bang Hui Yin, and Shi Mo Bai. "Vibro-Acoustic Coupling Analysis of Aero-Engine Combustion Chamber Model." Applied Mechanics and Materials 44-47 (December 2010): 4100–4104. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.4100.

Full text

Abstract:

The combustion instability is an important reason for fatigue failure of the vibro-acoustic coupling combustion chamber thin-walled structure. The vibro-acoustic coupling equations of closed cavity are derived; The vibro-acoustic coupling coefficient matrix is calculated, it indicates that couplings between the acoustic modes and the structure modes are strictly selective; The vibro-acoustic coupling characteristics of the finite length simply supported closed cylindrical space and the combustion chamber flame tube modals are studied with the finite element method, and the little effect of modal coupling on frequency value is founded; The vibro-acoustic coupling test validation of the combustion chamber flame tube model is completed, and the results show that both the structure modes of the flame tube and the acoustic modes have the phenomenon of weak coupling.

APA, Harvard, Vancouver, ISO, and other styles

41

Wu, Xian Xiang, Yan Ming, and Juan Wang. "Finite Element Analysis Based Ultrasonic Elastography." Advanced Materials Research 887-888 (February 2014): 632–36. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.632.

Full text

Abstract:

A variety of ultrasound elasticity imaging methods have been widely used in clinical. However, most of the existing methods are based on the assumption of organization for the pure elastic, and ignore the organization viscoelasticity effects on measurement results. In this paper, the finite element analysis method was used to calculate the different tissue deformation displacement distribution as well as the distribution of acoustic echo, etc. Using the theory of viscoelastic mechanics, we study the effects of viscoelastic parameters and sound pressure frequencies for the viscoelastic imaging of model organization. The experimental results of finite element analysis show that the viscosity of the organization cant be ignored in elastography.

APA, Harvard, Vancouver, ISO, and other styles

42

Liang, Bing Nan, and Hong Liang Yu. "Finite Element Parametric Acoustic Modeling and Analysis of Ship Floating Cabins." Applied Mechanics and Materials 333-335 (July 2013): 2146–50. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.2146.

Full text

Abstract:

The development of parametric calculation module program based on APDL, the completion of 3D acoustic modeling of a ship floating cabin, the selection of constraints according to the actual work situations, the finite element modal analysis of the overall cabin in the ANSYS environment and comparative analysis of a low-order vibration frequency of the cabin under different fire ratings. Acoustic calculation program of the fluid-structure interaction is used to analyze harmonic sound field and verify the impact of different thickness fireproof rockwools on the cabin acoustic performance. Parametric Design and Finite Element Analysis are combined to achieve the adjustment of the structural parameters of the complex models, automatically generate solid models and complete finite element analysis, which is important for the optimization of the acoustic design of the ship cabins.

APA, Harvard, Vancouver, ISO, and other styles

43

Joly, Nicolas, and Petr Honzík. "Numerical Modelling of Boundary Layers and Far Field Acoustic Propagation in Thermoviscous Fluid." Acta Acustica united with Acustica 105, no. 6 (November 1, 2019): 1137–48. http://dx.doi.org/10.3813/aaa.919392.

Full text

Abstract:

To model linear acoustics in a thermoviscous fluid in open domain and time-harmonic regime, a Finite Element formulation in a bounded meshed domain is combined with the integral representation of the field for the propagative solution. The integrals are non-singular and involve the only Finite Element node values for temperature variation and particle velocity variables. To overcome the non-uniqueness of solutions at fictitious resonant frequencies, a Burton-Miller combination of integral representation is used. This formulation is suitable to compute acoustic radiation, scattering and diffraction by objects or mutual interaction between transducers. Two-dimensional computational experiments are presented in an infinite, open domain (exterior), showing that the model can be achieved in meshing only a thin domain surrounding the physical boundaries of a device.

APA, Harvard, Vancouver, ISO, and other styles

44

Kuznetsov, A. V., A. A. Igolkin, A. I. Safin, and A. O. Pantyushin. "Mathematical model of acoustic characteristics of polyurethane foam used for sound absorption in aerospace engineering." VESTNIK of Samara University. Aerospace and Mechanical Engineering 20, no. 2 (July 9, 2021): 53–62. http://dx.doi.org/10.18287/2541-7533-2021-20-2-53-62.

Full text

Abstract:

When solving the problem of reducing the acoustic load on the spacecraft during the launch and flight of the launch vehicle, finite element modeling of acoustic processes under the nose fairing is carried out. To successfully solve this problem, a mathematical model of the acoustic characteristics of the material used for sound insulation is required. The existing mathematical models of the acoustic characteristics of materials are not suitable for the material under consideration that can be used in rocket and space technology to increase the sound insulation of the payload fairing + transfer compartment assembly. To obtain the sound absorption coefficient of the material, an impedance tube measurement method with two microphones is used. Using the method of differential evolution, the coefficients of a mathematical model of acoustic characteristics of the Delany-Bazley type for the specified material are selected. The sound absorption coefficient obtained experimentally and that calculated using the obtained model are compared; the average and maximum values of the error are shown. The resulting model will make it possible to carry out finite element modeling of acoustic and vibroacoustic processes under the nose fairing, taking into account the location of the sound-absorbing material.

APA, Harvard, Vancouver, ISO, and other styles

45

Li, Bin, Jian Li, Shilin Yan, Wenjie Yan, and Xu He. "Experiment and Simulation Analysis on Noise Attenuation of Al/MF Cylindrical Shells." Shock and Vibration 2017 (2017): 1–8. http://dx.doi.org/10.1155/2017/6980501.

Full text

Abstract:

For the issue concerning internal noise reduction of Al-made cylindrical shell structure, the noise control method of laying melamine foam (MF) layer is adopted for in-shell noise attenuation experiments of Al and Al/MF cylindrical shells and corresponding internal noise response spectrograms are obtained. Based on the Virtual.Lab acoustics software, a finite element model is established for the analysis of noise in the Al/MF cylinder shell and numerical simulation computation is conducted for the acoustic mode and in-shell acoustic response; the correctness of the finite element model is verified via comparison with measured data. On this basis, influence rules of different MF laying rate and different laying thickness on acoustic cavity resonance response within the low and medium frequency range of 100–400 Hz are studied. It is indicated that noise reduction increases with MF laying rate, but the amplification decreases along with the rising of MF laying rate; noise reduction per unit thickness decreases with the increase of laying thickness, while noise reduction per unit area increases.

APA, Harvard, Vancouver, ISO, and other styles

46

Marburg, Steffen. "A Pollution Effect in the Boundary Element Method for Acoustic Problems." Journal of Theoretical and Computational Acoustics 26, no. 02 (June 2018): 1850018. http://dx.doi.org/10.1142/s2591728518500184.

Full text

Abstract:

The pollution effect is a well-known and well-investigated phenomenon of the finite element method for wave problems in general and for acoustic problems in particular. It is understood as the problem that a local mesh refinement cannot compensate the numerical error which is generated and accumulated in other regions of the model. This is the case for the phase error of the finite element method which leads to dispersion resulting in very large numerical errors for domains with many waves in them and is of particular importance for low order elements. Former investigations have shown that a pollution effect resulting from dispersion is unlikely for the boundary element method. However, numerical damping in the boundary element method can account for a pollution effect. A further investigation of numerical damping reveals that it has similar consequences as the phase error of the finite element method. One of these consequences is that the number of waves within the domain may be controlling the discretization error in addition to the size and the order of the boundary elements. This will be demonstrated in computational examples discussing traveling waves in rectangular ducts. Different lengths, element types and mesh sizes are tested for the boundary element collocation method. In addition to the amplitude error which is due to numerical damping, a rather small phase error is observed. This may indicate numerical dispersion.

APA, Harvard, Vancouver, ISO, and other styles

47

Wilhelms, Reiner, and Chao‐Min Wu. "Finite element tongue model−Algorithms." Journal of the Acoustical Society of America 92, no. 4 (October 1992): 2391. http://dx.doi.org/10.1121/1.404763.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Cai, Deng Hui, and Xin Tan Ma. "Analysis of Acoustic Performance of Compound Muffler by Finite Element Method." Advanced Materials Research 529 (June 2012): 257–63. http://dx.doi.org/10.4028/www.scientific.net/amr.529.257.

Full text

Abstract:

Since the theory of one-dimensional plane wave can not accurately predict the internal sound field of the complex structure muffler. The three-dimensional finite element method is adopted to establish the acoustic model of the composite muffler based on the application of composite muffler model. Transmission loss and characteristics of internal sound field of the composite muffler's are calculated through acoustic vibration software Sysnoise. The calculation shows that the muffler under the interference of fluid flow has the higher transmission loss compared with the absence of liquidity function with an additional silencer band. The analysis method and conclusions provide a basis for the design of composite muffler.

APA, Harvard, Vancouver, ISO, and other styles

49

Kalateh, Farhoud, and Ali Koosheh. "Finite Element Analysis of Flexible Structure and Cavitating Nonlinear Acoustic Fluid Interaction under Shock Wave Loading." International Journal of Nonlinear Sciences and Numerical Simulation 19, no. 5 (July 26, 2018): 459–73. http://dx.doi.org/10.1515/ijnsns-2016-0135.

Full text

Abstract:

AbstractThis paper describes a numerical model and its finite element implementation that used to compute the cavitation effects on nonlinear acoustic fluid and adjacent flexible structure interaction. The system is composed of two sub-systems, namely, the fluid and the flexible flat plate. A fully coupled approach using iterative implicit partitioned scheme was implemented in the present work which can account for the effects associated whit a mutual interaction. This approach included a compressible nonlinear acoustic fluid Eulerian solver and a Lagrangian solver for the flexible structure both in finite element formulation. A novel implementation of acoustic cavitation was made possible with the introduction of a simplified one-fluid cavitation model. The element-by-element PCG (Preconditioned Conjugate Gradient) solver together with diagonal preconditioning is used to solve the large equation system resulting from the finite element discretization of the governing equation of fluid domain. The capability of three different cavitation model, as the cut-off model, Modified Schmidt model and developed model are compared with each other in the evaluation of plate vibration response. Simulation results are presented on a large size shock tube, in which planar shock waves were impacting in “face on” configuration flat plates mounted at tube's end. Results are presented to demonstrate the capability of proposed solver in simulating cavitating nonlinear acoustic fluid. Obtained results show that impact forces caused impinging shock wave and reloading by cavitating region collapse have a considerable effect on the dynamic response of flexible plate.

APA, Harvard, Vancouver, ISO, and other styles

50

Li, Pengbo, Yunju Yan, and Huagang Lin. "Numerical simulation and experimental researches on the vibration–acoustic coupled property of an aircraft model under strong reverberation noise." Journal of Vibration and Control 23, no. 17 (January 25, 2016): 2757–66. http://dx.doi.org/10.1177/1077546315621417.

Full text

Abstract:

In order to predict the characteristics of the vibration–acoustic coupling of an aircraft model, the finite element method–boundary element method of dynamic model (FEM-BEM dynamic model) is established. The numerical calculations and experiments of the structural vibration acceleration responses and the sound pressure levels in the model cabin under the strong noise excitations are carried out in the low and middle frequency area. By comparing the results of experiments and simulations, it’s found that the structural vibration responses and the sound pressure responses mainly distribute in the range of low and medium frequency, in which the simulated and experimental results also match each other well. This indicates the established finite element/boundary element vibration–acoustic coupled dynamic model and the calculation method proposed in this study are feasible.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Acoustic finite element model'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles