Structural Acoustics Applications of the BEM and the FEM
|
|
- August Osborne
- 5 years ago
- Views:
Transcription
1 Structural Acoustics Applications of the BEM and the FEM A. F. Seybert, T. W. Wu and W. L. Li Department of Mechanical Engineering, University of Kentucky Lexington, KY U.S.A. SUMMARY In this paper we discuss how the boundary element method (BEM) may be used by itself or in conjunction with the finite element method (FEM) for the solution of problems in structural acoustics. Problems in this category include: the scattering of sound from an elastic solid or shell submerged in a heavy fluid such as sea water, and the sound field generated within a vehicle passenger compartment or aircraft cabin due to vibration of the surrounding structure. In the latter case, the modes of the structure and the acoustic fluid may be coupled even if the fluid is air. Two approaches to structural acoustics modeling are considered. In one approach, the BEM is used to model both the elastic and the acoustic parts of the problem. In the second approach, the FEM is used to model the structure, while the BEM is used to model the fluid. INTRODUCTION The interaction of sound and vibration is an important subject in acoustics. If a light fluid is contained within a vibrating structure, such as the air within a vehicle passenger compartment, there may be significant coupling between the structural vibration and the sound field. In such cases, the coupled structural/acoustics problem must be solved. When a structure is submerged in a heavy fluid, such as sea water, the vibration of the structure will be affected by the surrounding sound pressure, and the whole system becomes a coupled structural/acoustics problem. There have been many papers published using a variety of analytical methods to examine structural/acoustic interaction [1-5]. However, when the structure has an arbitrary shape, methods amenable to numerical implementation are usually more desirable than approximate analytical methods. In this paper we use two numerical techniques to solve problems in structural acoustics. In the first approach, the coupled elastic/acoustic boundary value problem is reformulated into a pair of integral equations, one for the interior (elastic) domain and one for the exterior (acoustic) domain. In its numerical form the integral equation method is referred to B. S. Annigeri et al. (eds.), Boundary Element Methods in Engineering Springer-Verlag Berlin Heidelberg 1990
2 537 as the boundary element method (BEM). The coupled elastic/acoustic technique used herein is referred to as the BEM/BEM approach. The second numerical technique uses a finite element method (FEM) for the structure, but retains the BEM for the fluid. We refer to this method as the FEM/BEM approach. The FEM/BEM approach is preferred for structural acoustics problems in which the structural geometry is complex or when the structure is a thin shell. In the latter case, a BEM model of the structure would not be practical because the elements would be very small to avoid the near-singular behavior caused by the thin structural domain. FORMUlATION For acoustic radiation or scattering from an elastic structure, we must solve a boundary value problem involving coupling between the elastic structure B2, bounded by the surface S, and the surrounding acoustic fluid Bl, see Fig. 1. (Similarly, we may pose a problem consisting of an acoustic fluid, bounded by a surface S, contained within an elastic structure B2 bounded on the exterior by a surface s). For scattering problems, we denote the prescribed incident wave as Pi. The elastic structure is assumed to be homogeneous, isotropic and linearly elastic, and the fluid is assumed to be inviscid. Body forces are assumed zero. Boundary conditions may be specified along the surfaces sand S. Along s, where Bl and B2 are not in contact, we may impose surface tractions, ---APi 5 Fig. 1. Nomenclature for radiation or scattering of acoustic waves from an elastic structure.
3 538 surface displacements, or a linear combination of the two, corresponding to a well-posed boundary value problem. The appropriate boundary conditions at the interface S are continuity of normal displacement of the structure and the particle displacement of the fluid and equilibrium of the normal stress on the structure and the acoustic pressure. of the problem may be found in Reference 6). (A complete statement BEM/BEM FORMULATION To reformulate the problem in Fig. 1 in terms of integral equations valid at the boundary S + s, we use the boundary integral equation for the exterior acoustics problem and a companion interior integral equation the elastic structure. The resulting boundary integral equation formulation for our coupled problem is [6]: for TIT C (P2)y(P 2 ) - [y (P2,Q)~(Q) - T (P2,Q)y(Q)] ds(q), s+s (1) which is valid for P2 in B2 or on S + sand C(Pl)P(Pl ) = I [ p(q) :~(Pl,Q) - ~(Q) ~(Pl,Q)J ds(q) + 4~Pi(Pl)' (2) S which is valid for PI in HI or on S. In the above equations, ~ and! are the Stokes' displacement and traction tensors, respectively, ~(Pl,Q) is the free-space Green function, ~ and t are the displacement and the stress, respectively, in the elastic structure and p and ap/an are the sound pressure and the normal derivative of the sound pressure, respectively, in the acoustic fluid. Special care has to be used in integrating Eqs. (1) and (2) numerically due to the singularities in the integrands. However, it is noted that both integrals exist. A numerical solution to Eqs. (1) and (2) can be achieved by discretizing the boundary into a number of surface elements. In this paper, we use isoparametric quadratic elements [6]. In numerical form Eq. (1) becomes [H]lu) - [a]lt) (3) where H and a are the assembled coefficient matrices resulting from the numerical integration. The momentum equation is used to replace the normal derivative of the pressure in Eq. (2) with displacement, and the resulting numerical form of Eq. (2) is
4 539 where T and D are the assembled coefficient matrices. The coupled elastic/acoustic system of equations can be obtained by combining Eqs. (3) and (4) and replacing the tractions on the surface with pressure. The resulting linear system of equations can be solved for the nodal values of displacements and acoustic pressure on the elastic/acoustic interface as well as the displacements (or tractions) on the inner solid surface. FEM/BEM FORMULATION Although, theoretically, there is no limitation on the closeness between the outer surface S and the inner surface s, the BEM/BEM approach will require a large number of integration points and elements if the elastic structure is an extremely thin shell. An alternative way to model an elastic thin shell is the finite element method [7]. If we use the FEM to model the elastic thin shell and the BEM to model the acoustic field, the resulting matrix representation is L -D ] [ :] [ f ] (5) where K is the stiffness matrix, M is the mass matrix, f is the forcing vector due to the applied loading, and L takes care of the loading from the sound pressure at the interface. X, Fig. 2. One octant of the outer surface of the sphere showing nodes and element configuration.
5 540 EXAMPLE PROBLEMS We tested the BEM/BEM and the FEM/BEM methods by solving several problems in structural acoustics having spherical geometry. these problems is shown in Fig. 2. A typical mesh used in The first problem that we consider is the radiation from a hollow steel sphere in sea water with inner radius b = 0.5 m and outer radius a - 1 m. The inner surface is loaded with a uniform time-harmonic pressure of amplitude Po. shell, the BEM/BEM technique is used. As this is a thick, homogeneous Figure 3 shows the sound pressure at a distance of 3a from the center of the hollow sphere plotted versus ka where k is the wave number in the fluid. The data in Fig. 3 show the rapid convergence that may be expected with the BEM/BEM.. The numerical solution, however, is not as good at the resonance frequency (ka-8) as it is at other frequencies. Our numerical study showed that the error at ka=8 will be reduced to 0.7 percent if a mesh of 386 nodes is used. Next, we consider a BEM/BEM test case consisting of the scattering of an incident plane wave of amplitude Pi by the hollow sphere described above. Figure 4 shows the ratio of the scattered pressure to the incident pressure at a distance of 3a from the center of the sphere for a sphere of various composition when ka = 1. from the right in Fig. 4. The plane wave is incident on the hollow sphere The results for the rigid sphere are also shown , Analytical o Bem 114 Nodes Bem 58 Nodes Fig. 3. ka Normalized sound pressure at a distance of 3a from the center of a hollow steel sphere in sea water excited by an uniform internal pressure Po.
6 in Fig. 4 for comparison. the 114 node BEM/BEM model discussed above. All of the scattering data were obtained with The effect of material composition on the scattered pressure may be seen quite clearly in Fig , , , - RiOid -- Steel --- Aluminum ---- Rubber tH-f-1:---+-l--f-f--t '-- --L....L...L- ~ Fig. 4. Ratio of the scattered to the incident pressure at a distance of 3a from the center of a hollow sphere of various compositions in sea water when ka - 1. AN INTERIOR STRUCTURAL/ACOUSTICS PROBLEM As a test of the FEMjBEM technique, consider an air-filled spherical aluminum shell of radius I m and thickness 5 rom excited externally by a uniform pressure of 1 Pa (94 db sound pressure level). Figure 5 shows the sound pressure level at the center of the spherical cavity as a function of frequency. The frequency regions where the sound pressure level is high correspond to the resonances of the air cavity within the shell. DISCUSSION AND SUMMARY Two numerical methods have been used to solve structural acoustics problems. In the BEM/BEM method, we have reformulated the acoustic radiation and scattering problems for elastic structures in terms of a pair of integral equations, one for the elastic structure, the other for the host fluid and both valid at the interface. These integral equations were reduced to a numerical form using quadratic isoparametric elements. The BEM/BEM formulation was tested with good results for several radiation
7 542 iii" e '"" so 1'4 II: ~ fii gj 40 IE Q :z: ~ 230 *\* I. *V' * BEMAP/ANSYS ANALYTICAL 20 Fig FREQUENCY (HZ) Sound pressure level at the center of a air-filled aluminum shell of radius 1 m and thickness 5 mm due to a uniform external pressure of 94 db. and scattering problems of practical importance. For elastic thin shells, the BEM/BEM approach is still quite reliable if more integration points are used to integrate the integral equations for very close elements. However, a coupled FEM/BEM technique also provides excellent results for thin shell problems. In addition, the FEM/BEM method is more practical in cases where the structure has a complex geometry. approach showed good results. A test problem using the FEM/BEM 1. J. J. Faran, Jr., "Sound Scattering by Solid Cylinders and Spheres," J. Acoust. Soc. Am. 23, , (1951). 2. M. C. Junger, "Sound Scattering by Thin Elastic Shells," J. Acoust. Soc. Am. 24, (1952). 3. R. Hickling, "Analysis of Echoes from a solid Elastic Sphere in Water," J. Acoust. Soc. Am. 34, 1582 (1962). 4. K. Yosioka and Y. Kawasima, "Acoustic Radiation Pressure on a Compressible Sphere," Acustica 5, (1955). 5. T. Hasegawa and K. Yosioka, "Acoustic-Radiation Force on a Solid Elastic Sphere," J. Acoust. Soc. Am. 46, (1969). 6. A. F. Seybert, T. W. Wu and X. F. Wu, "Radiation and Scattering of Acoustic Waves from Elastic Solids and Shells using the Boundary Element Method," J Acoust. Soc. Am. 84, (1988). 7. D. T. Wilton, "Acoustic Radiation and Scattering from Elastic Structures," Int. J. Num. Meth. En&.. 13, (1978).
Effects of mass distribution and buoyancy on the sound radiation of a fluid loaded cylinder
Effects of mass distribution and buoyancy on the sound radiation of a fluid loaded cylinder Hongjian Wu, Herwig Peters, Roger Kinns and Nicole Kessissoglou School of Mechanical and Manufacturing, University
More informationAcoustic radiation by means of an acoustic dynamic stiffness matrix in spherical coordinates
Acoustic radiation by means of an acoustic dynamic stiffness matrix in spherical coordinates Kauê Werner and Júlio A. Cordioli. Department of Mechanical Engineering Federal University of Santa Catarina
More informationin the CBIE when it is applied to domains surrounding INTRODUCTION
A unified boundary element method for the analysis of sound and shell-like structure interactions. I. Formulation and verification haohai Chen and Yijun Liu a) Department of Mechanical, Industrial and
More informationTransactions on Modelling and Simulation vol 3, 1993 WIT Press, ISSN X
Boundary element method in the development of vehicle body structures for better interior acoustics S. Kopuz, Y.S. Unliisoy, M. Qali kan Mechanical Engineering Department, Middle East Technical University,
More informationSound radiation from nested cylindrical shells
Sound radiation from nested cylindrical shells Hongjian Wu 1 ; Herwig Peters 1 ; Nicole Kessissoglou 1 1 School of Mechanical and Manufacturing Engineering, UNSW Australia, Sydney NSW 252 ABSTRACT Fluid-loaded
More informationNew Developments of Frequency Domain Acoustic Methods in LS-DYNA
11 th International LS-DYNA Users Conference Simulation (2) New Developments of Frequency Domain Acoustic Methods in LS-DYNA Yun Huang 1, Mhamed Souli 2, Rongfeng Liu 3 1 Livermore Software Technology
More informationPrediction of the radiated sound power from a fluid-loaded finite cylinder using the surface contribution method
Prediction of the radiated sound power from a fluid-loaded finite cylinder using the surface contribution method Daipei LIU 1 ; Herwig PETERS 1 ; Nicole KESSISSOGLOU 1 ; Steffen MARBURG 2 ; 1 School of
More informationFEM/FMBEM coupling for acoustic structure interaction and acoustic design sensitivity analysis with sound-absorbing materials
Boundary Elements and Other Mesh Reduction Methods XXXVIII 113 FEM/FMBEM coupling for acoustic structure interaction and acoustic design sensitivity analysis with sound-absorbing materials Y. M. Xu, H.
More informationEfficient calculation for evaluating vast amounts of quadrupole sources in BEM using fast multipole method
PROCEEDINGS of the 22 nd International Congress on Acoustics Boundary Element and Meshless Methods on Acoustics and Vibrations: Paper ICA2016-309 Efficient calculation for evaluating vast amounts of quadrupole
More informationNUMERICAL MODELLING OF RUBBER VIBRATION ISOLATORS
NUMERICAL MODELLING OF RUBBER VIBRATION ISOLATORS Clemens A.J. Beijers and André de Boer University of Twente P.O. Box 7, 75 AE Enschede, The Netherlands email: c.a.j.beijers@utwente.nl Abstract An important
More informationFastBEM Acoustics. Verification Manual , Advanced CAE Research, LLC (ACR) Cincinnati, Ohio, USA All Rights Reserved
FastBEM Acoustics Verification Manual 2007-2017, Advanced CAE Research, LLC (ACR) Cincinnati, Ohio, USA All Rights Reserved www.fastbem.com Copyright 2007-2017, Advanced CAE Research, LLC, All Rights Reserved
More informationNumerical Prediction of the Radiated Noise of Hermetic Compressors Under the Simultaneous Presence of Different Noise Sources
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 1998 Numerical Prediction of the Radiated Noise of Hermetic Compressors Under the Simultaneous
More informationSimulation of acoustic and vibroacoustic problems in LS-DYNA using boundary element method ABSTRACT:
Simulation of acoustic and vibroacoustic problems in LS-DYNA using boundary element method Yun Hang, Mhamed Souli, Rogelio Perez Livermore Software Technology Corporation USA & University of Lille Laboratoire
More informationInternational Journal of Scientific & Engineering Research, Volume 5, Issue 7, July-2014 ISSN
ISSN 2229-5518 692 In literature, finite element formulation uses beam element or plate element for structural modelling which has a limitation on transverse displacement. Atkinson and Manrique [1] studied
More informationModeling and Analysis of Spacecraft Structures Subject to Acoustic Excitation
Modeling and Analysis of Spacecraft Structures Subject to Acoustic Excitation Harijono Djojodihardjo Professor, Universiti Sains Malaysia harijono@djojodihardjo.com and Irtan Safari Graduate Student, Universiti
More informationCoupling the BEM/TBEM and the MFS for the numerical simulation of acoustic wave propagation and transient conduction heat transfer
Boundary Elements and Other Mesh Reduction Methods XXXII 261 Coupling the BEM/TBEM and the MFS for the numerical simulation of acoustic wave propagation and transient conduction heat transfer A. Tadeu
More informationMODELLING AND MEASUREMENT OF BACKSCATTERING FROM PARTIALLY WATER-FILLED CYLINDRICAL SHELLS
MODELLING AND MEASUREMENT OF BACKSCATTERING FROM PARTIALLY WATER-FILLED CYLINDRICAL SHELLS Victor Humphrey a, Lian Sheng Wang a and Nisabha Jayasundere b a Institute of Sound & Vibration Research, University
More informationICSV14 Cairns Australia 9-12 July, 2007
ICSV14 Cairns Australia 9-1 July, 7 STUDY ON THE CHARACTERISTICS OF VIBRATION AND ACOUSTIC RADIATION OF DAMAGED STIFFENED PANELS Hong Ming 1, Guo Xin-yi, Liu Lian-hai 3 and Li Gen-tian 4 1 Department of
More informationGraduate School of Engineering, Kyoto University, Kyoto daigaku-katsura, Nishikyo-ku, Kyoto, Japan.
On relationship between contact surface rigidity and harmonic generation behavior in composite materials with mechanical nonlinearity at fiber-matrix interface (Singapore November 2017) N. Matsuda, K.
More informationBEM Methods for Acoustic and Vibroacoustic Problems in LS-DYNA
12 th International LS-DYNA Users Conference Simulation(2) BEM Methods for Acoustic and Vibroacoustic Problems in LS-DYNA Mhamed Souli, Yun Huang, Rongfeng Liu Livermore Software Technology Corporation
More informationA DECOUPLED VIBRO-ACOUSTIC EXTENSION OF NASTRAN
Twelfth International Congress on Sound and Vibration A DECOUPLED VIBRO-ACOUSTIC EXTENSION OF NASTRAN Philippe JEAN and Hugo SIWIAK Centre Scientifique et Technique du Bâtiment 24 rue Joseph Fourier F-
More informationProceedings of Meetings on Acoustics
Proceedings of Meetings on Acoustics Volume 19, 13 http://acousticalsociety.org/ ICA 13 Montreal Montreal, Canada - 7 June 13 Structural Acoustics and Vibration Session 4aSA: Applications in Structural
More informationStress analysis of a stepped bar
Stress analysis of a stepped bar Problem Find the stresses induced in the axially loaded stepped bar shown in Figure. The bar has cross-sectional areas of A ) and A ) over the lengths l ) and l ), respectively.
More informationEfficient boundary element analysis of periodic sound scatterers
Boundary Element and Meshless Methods in Acoustics and Vibrations: Paper ICA2016-418 Efficient boundary element analysis of periodic sound scatterers M. Karimi, P. Croaker, N. Kessissoglou 1 School of
More informationFLINOVIA 2017, State Collage, USA. Dr. Alexander Peiffer, Dr. Uwe Müller 27 th -28 th April 2017
Review of efficient methods for the computation of transmission loss of plates with inhomogeneous material properties and curvature under turbulent boundary layer excitation FLINOVIA 2017, State Collage,
More informationSimulation of Acoustic and Vibro-Acoustic Problems in LS-DYNA using Boundary Element Method
10 th International LS-DYNA Users Conference Simulation Technolog (2) Simulation of Acoustic and Vibro-Acoustic Problems in LS-DYNA using Boundar Element Method Yun Huang Livermore Software Technolog Corporation
More informationVibration of Thin Beams by PIM and RPIM methods. *B. Kanber¹, and O. M. Tufik 1
APCOM & ISCM -4 th December, 23, Singapore Vibration of Thin Beams by PIM and RPIM methods *B. Kanber¹, and O. M. Tufik Mechanical Engineering Department, University of Gaziantep, Turkey. *Corresponding
More informationPrediction of Transformer Core Noise
Prediction of Transformer Core Noise R. Haettel *,1, M. Kavasoglu 1, A. Daneryd 1 and C. Ploetner 2 1 ABB Corporate Research Sweden, 2 ABB Transformers Canada *Corresponding author: 721 78 Västerås Sweden,
More informationMuffler Transmission Loss Simple Expansion Chamber
Muffler Transmission Loss Simple Expansion Chamber 1 Introduction The main objectives of this Demo Model are Demonstrate the ability of Coustyx to model a muffler using Indirect model and solve the acoustics
More information1 Introduction. 2 Boundary Integral Equations
Analysis of sound transmission through a thin elastic plate by using boundary integral equations T. Terai*, Y. Kawai* "Department ofarchitecture, Faculty ofengineering, Kinki University, 1 Umenobe Takaya,
More informationConvergence of modes in exterior acoustics problems with infinite elements
INTER-NOISE 216 Convergence of modes in exterior acoustics problems with infinite elements Lennart Moheit 1 ; Steffen Marburg Chair of Vibroacoustics of Vehicles and Machines Technische Universität München,
More informationStructural Dynamics. Spring mass system. The spring force is given by and F(t) is the driving force. Start by applying Newton s second law (F=ma).
Structural Dynamics Spring mass system. The spring force is given by and F(t) is the driving force. Start by applying Newton s second law (F=ma). We will now look at free vibrations. Considering the free
More informationTransactions on Modelling and Simulation vol 7, 1994 WIT Press, ISSN X
Vibration and sound radiation by baffled and constrained shells P.-O. Mattel Laboratoire de Mecanique et d'acoustique, C.N.R.S. 31 Chemin Joseph Aiguier, 13042 Marseille cedex 20, France ABSTRACT A cylindrical
More informationPrediction of High-frequency Vibro-acoustic Coupling in Anechoic Chamber Using Energy Finite Element Method and Energy Boundary Element Method
Copyright 2012 Tech Science ress CMES, vol.85, no.1, pp.65-78, 2012 rediction of High-frequency Vibro-acoustic Coupling in Anechoic Chamber Using Energy Finite Element Method and Energy Boundary Element
More informationChapter 2 Finite Element Formulations
Chapter 2 Finite Element Formulations The governing equations for problems solved by the finite element method are typically formulated by partial differential equations in their original form. These are
More informationPoint Excitation of a Coupled Structural-Acoustical Tire Model with Experimental Verification
Purdue University Purdue e-pubs Publications of the Ray W. Herrick Laboratories School of Mechanical Engineering 8-2015 Point Excitation of a Coupled Structural-Acoustical Tire Model with Experimental
More informationDepartment of Structural, Faculty of Civil Engineering, Architecture and Urban Design, State University of Campinas, Brazil
Blucher Mechanical Engineering Proceedings May 2014, vol. 1, num. 1 www.proceedings.blucher.com.br/evento/10wccm A SIMPLIFIED FORMULATION FOR STRESS AND TRACTION BOUNDARY IN- TEGRAL EQUATIONS USING THE
More informationMAXIMUM ENTROPY-BASED UNCERTAINTY MODELING AT THE FINITE ELEMENT LEVEL. Pengchao Song and Marc P. Mignolet
MAXIMUM ENTROPY-BASED UNCERTAINTY MODELING AT THE FINITE ELEMENT LEVEL Pengchao Song and Marc P. Mignolet SEMTE, Faculties of Mechanical and Aerospace Engineering, Arizona State University, 51 E. Tyler
More informationParametric Investigation of the Common Geometry Shapes for Added Mass Calculation
Parametric Investigation of the Common Geometry Shapes for Added Mass Calculation Afsoun Koushesh* and Jin Lee Department of Mechanical Engineering, American University of Sharjah, Sharjah, UAE *Corresponding
More information1817. Research of sound absorption characteristics for the periodically porous structure and its application in automobile
1817. Research of sound absorption characteristics for the periodically porous structure and its application in automobile Xian-lin Ren School of Mechatronics Engineering, University of Electronic Science
More informationA Modal Approach to Lightweight Partitions with Internal Resonators
A Modal Approach to Lightweight Partitions with Internal Resonators Steffen Hettler, Philip Leistner Fraunhofer-Institute of Building Physics, D-7569 Stuttgart, Nobelstrasse, Germany e-mail: hettler@ibp.fraunhofer.de,
More informationIMPROVED STRUCTURE-ACOUSTIC INTERACTION MODELS, PART II: MODEL EVALUATION Guseong-dong, Yuseong-gu, Daejeon Republic of Korea
ICSV14 Cairns Australia 9-12 July, 2007 IMPROVED STRUCTURE-ACOUSTIC INTERACTION MODELS, PART II: MODEL EVALUATION Abstract Moonseok Lee 1 *, Youn-Sik Park 1, Youngjin Park 1, K.C. Park 2 1 NOVIC, Department
More informationCHAPTER 8: Thermal Analysis
CHAPER 8: hermal Analysis hermal Analysis: calculation of temperatures in a solid body. Magnitude and direction of heat flow can also be calculated from temperature gradients in the body. Modes of heat
More informationComputational Acoustics by Means of Finite and Boundary Elements for Woofers, Tweeters, Horns and Small Transducers
Computational Acoustics by Means of Finite and Boundary Elements for Woofers, Tweeters, Horns and Small Transducers Alfred J. Svobodnik NAD - Numerical Analysis and Design GmbH & Co KG as@nadwork.at http://www.nadwork.at
More informationNotes on Absorption and Impedance Measurements
Notes on Absorption and Impedance Measurements Andrew F. Seybert University of Kentucky Lexington, KY 456-18 859-257-6336 x 8645 seybert@engr.uky.edu Applicable Standards. There are two standards 1,2 for
More informationA Coupled FEM-BEM Formulation in Structural Acoustics for Imaging a Material Inclusion
A Coupled FEM-BEM Formulation in Structural Acoustics for Imaging a Material Inclusion Abhiit Sarkar, Venkata R. Sonti and Rudra Pratap Facility for Research in Technical Acoustics, Department of Mechanical
More informationA MODIFIED DECOUPLED SCALED BOUNDARY-FINITE ELEMENT METHOD FOR MODELING 2D IN-PLANE-MOTION TRANSIENT ELASTODYNAMIC PROBLEMS IN SEMI-INFINITE MEDIA
8 th GRACM International Congress on Computational Mechanics Volos, 2 July 5 July 205 A MODIFIED DECOUPLED SCALED BOUNDARY-FINITE ELEMENT METHOD FOR MODELING 2D IN-PLANE-MOTION TRANSIENT ELASTODYNAMIC
More informationChapter 2. Formulation of Finite Element Method by Variational Principle
Chapter 2 Formulation of Finite Element Method by Variational Principle The Concept of Variation of FUNCTIONALS Variation Principle: Is to keep the DIFFERENCE between a REAL situation and an APPROXIMATE
More informationHybrid boundary element formulation in acoustics
Hybrid boundary element formulation in acoustics L. Gaul, M. Wagner Institute A of Mechanics, University of Stuttgart, Germany. Abstract A symmetric hybrid boundary element method in the frequency domain
More informationInvestigation of Passive Control Devices for Potential Application to a Launch Vehicle Structure to Reduce the Interior Noise Levels During Launch
Investigation of Passive Control Devices for Potential Application to a Launch Vehicle Structure to Reduce the Interior Noise Levels During Launch Report for Stage 4 Tasks 1 and 2 July 24 Prepared For:
More informationTHE objective of this paper is to present an analytical approach
AIAA JOURNAL Vol. 45, No. 6, June 2007 Sensitivity Analysis and Optimization Using Energy Finite Element and Boundary Element Methods Jun Dong and Kyung K. Choi University of Iowa, Iowa City, Iowa 52242
More informationBack Analysis of Measured Displacements of Tunnels
Rock Mechanics and Rock Engineering 16, 173--180 (1983) Rock Mechanics and Rock Engineering 9 by Springer-Verlag 1983 Back Analysis of Measured Displacements of Tunnels By S. Sakurai and K. Takeuchi Kobe
More informationON THE MODELING AND SIMULATION OF AN ACOUSTIC CLOAK
5 th International Conference Advanced Composite Materials Engineering COMAT 014 16-17 October 014, Braşov, Romania ON THE MODELING AND SIMULATION OF AN ACOUSTIC CLOAK Veturia Chiroiu 1, Rodica Ioan 1,,
More informationDETC98/PTG-5788 VIBRO-ACOUSTIC STUDIES OF TRANSMISSION CASING STRUCTURES
Proceedings of DETC98: 1998 ASME Design Engineering Technical Conference September 13-16, 1998, Atlanta, GA DETC98/PTG-5788 VIBRO-ACOUSTIC STUDIES O TRANSMISSION CASING STRUCTURES D. Crimaldi Graduate
More informationL e c t u r e. D r. S a s s a n M o h a s s e b
The Scaled smteam@gmx.ch Boundary Finite www.erdbebenschutz.ch Element Method Lecture A L e c t u r e A1 D r. S a s s a n M o h a s s e b V i s i t i n g P r o f e s s o r M. I. T. C a m b r i d g e December
More informationSPECIAL DYNAMIC SOIL- STRUCTURE ANALYSIS PROCEDURES DEMONSTATED FOR TWO TOWER-LIKE STRUCTURES
2010/2 PAGES 1 8 RECEIVED 21. 9. 2009 ACCEPTED 20. 1. 2010 Y. KOLEKOVÁ, M. PETRONIJEVIĆ, G. SCHMID SPECIAL DYNAMIC SOIL- STRUCTURE ANALYSIS PROCEDURES DEMONSTATED FOR TWO TOWER-LIKE STRUCTURES ABSTRACT
More informationIdentification of Noise Sources by Means of Inverse Finite Element Method
Excerpt from the Proceedings of the COMSOL Conference 2008 Hannover Identification of Noise Sources by Means of Inverse Finite Element Method M. Weber *,1, T. Kletschkowski 2 and B. Samtleben 3 1,2 Helmut-Schmidt-University
More informationON THE PREDICTION OF EXPERIMENTAL RESULTS FROM TWO PILE TESTS UNDER FORCED VIBRATIONS
Transactions, SMiRT-24 ON THE PREDICTION OF EXPERIMENTAL RESULTS FROM TWO PILE TESTS UNDER FORCED VIBRATIONS 1 Principal Engineer, MTR & Associates, USA INTRODUCTION Mansour Tabatabaie 1 Dynamic response
More informationANALYSIS OF NATURAL FREQUENCIES OF DISC-LIKE STRUCTURES IN WATER ENVIRONMENT BY COUPLED FLUID-STRUCTURE-INTERACTION SIMULATION
6 th IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, September 9-11, 15, Ljubljana, Slovenia ANALYSIS O NATURAL REQUENCIES O DISC-LIKE
More informationTransient Analysis of Disk Brake By using Ansys Software
Transient Analysis of Disk Brake By using Ansys Software G. Babukanth & M. Vimal Teja Department of Mechanical Engineering, Nimra College of Engineering & Technology, Ibrahimpatnam, Vijayawada E-mail :
More informationAN ALTERNATIVE TECHNIQUE FOR TANGENTIAL STRESS CALCULATION IN DISCONTINUOUS BOUNDARY ELEMENTS
th Pan-American Congress of Applied Mechanics January 04-08, 00, Foz do Iguaçu, PR, Brazil AN ALTERNATIVE TECHNIQUE FOR TANGENTIAL STRESS CALCULATION IN DISCONTINUOUS BOUNDARY ELEMENTS Otávio Augusto Alves
More informationEFFECTS OF RESERVOIR LENGTH ON DYNAMIC ANALYSIS OF CONCRETE GRAVITY DAMS
The th October -,, Beijing, China EFFECTS OF RESERVOIR LENGTH ON DYNAMIC ANALYSIS OF CONCRETE GRAVITY DAMS A. Fathi and V. Lotfi M.Sc. Student, Dept. of Civil and Environmental Engineering, Amirkabir University
More informationTransactions on Modelling and Simulation vol 10, 1995 WIT Press, ISSN X
The receptance method applied to the free vibration of a circular cylindrical shell filled with fluid and with attached masses M. Amabili Dipartimento di Meccanica, Universita di Ancona, 1-60131 Ancona,
More informationTransactions on Modelling and Simulation vol 12, 1996 WIT Press, ISSN X
Plate-soil elastodynamic coupling using analysis S.F.A. Baretto, H.B. Coda, W.S. Venturini Sao Carlos School of Engineering, University ofsao Paulo, Sao Carlos - SP, Brazil BEM Abstract The aim of this
More informationOptimization for heat and sound insulation of honeycomb sandwich panel in thermal environments
Optimization for heat and sound insulation of honeycomb sandwich panel in thermal environments Jinlong Yuan 1, Haibo Chen 2, Qiang Zhong 3, Kongjuan Li 4 Department of Modern mechanics, University of Science
More informationFinn Jacobsen c) Department of Acoustic Technology, Technical University of Denmark, Ørsteds Plads, Building 352, DK-2800 Kgs.
On the modeling of narrow gaps using the standard boundary element method Vicente Cutanda a) Brüel & Kjær Sound & Vibration, Skodsborgvej 307, DK-2850 Nærum, Denmark Peter Møller Juhl b) ITF Institute
More informationAEROELASTIC ANALYSIS OF SPHERICAL SHELLS
11th World Congress on Computational Mechanics (WCCM XI) 5th European Conference on Computational Mechanics (ECCM V) 6th European Conference on Computational Fluid Dynamics (ECFD VI) E. Oñate, J. Oliver
More informationVIBRATION ENERGY FLOW IN WELDED CONNECTION OF PLATES. 1. Introduction
ARCHIVES OF ACOUSTICS 31, 4 (Supplement), 53 58 (2006) VIBRATION ENERGY FLOW IN WELDED CONNECTION OF PLATES J. CIEŚLIK, W. BOCHNIAK AGH University of Science and Technology Department of Robotics and Mechatronics
More informationStatic pressure and temperature coefficients of working standard microphones
Static pressure and temperature coefficients of working standard microphones Salvador BARRERA-FIGUEROA 1 ; Vicente CUTANDA-HENRÍQUEZ ; Antoni TORRAS-ROSELL 3 1,3 Danish Fundamental Metrology (DFM) A/S,
More informationSCATTERING OF SH WAVES BY CRACKS AND DELAMINATIONS
SCATTERING OF SH WAVES BY CRACKS AND DELAMINATIONS IN A CLADDED PLATE INTRODUCTION R. L. Bratton and S. K. Datta Department of Mechanical Engineering and CIRES University of Colorado Boulder, CO 80309-0427
More informationSIMULATION OF ORGAN PIPES ACOUSTIC BEHAVIOR BY MEANS OF VARIOUS NUMERICAL TECHNIQUES
SIMULATION OF ORGAN PIPES ACOUSTIC BEHAVIOR BY MEANS OF VARIOUS NUMERICAL TECHNIQUES Péter Rucz, Fülöp Augusztinovicz, Péter Fiala Budapest University of Technology and Economics Department of Telecommunications
More informationVibro-acoustic Analysis for Noise Reduction of Electric Machines
Vibro-acoustic Analysis for Noise Reduction of Electric Machines From Flux to OptiStruct Example : Synchronous Machine Flux 2D coupling to OptiStruct Patrick LOMBARD Application Team Manager Patrick.Lombard@cedrat.com
More informationFinite Element Method in Geotechnical Engineering
Finite Element Method in Geotechnical Engineering Short Course on + Dynamics Boulder, Colorado January 5-8, 2004 Stein Sture Professor of Civil Engineering University of Colorado at Boulder Contents Steps
More informationDHANALAKSHMI COLLEGE OF ENGINEERING, CHENNAI DEPARTMENT OF MECHANICAL ENGINEERING ME 6603 FINITE ELEMENT ANALYSIS PART A (2 MARKS)
DHANALAKSHMI COLLEGE OF ENGINEERING, CHENNAI DEPARTMENT OF MECHANICAL ENGINEERING ME 6603 FINITE ELEMENT ANALYSIS UNIT I : FINITE ELEMENT FORMULATION OF BOUNDARY VALUE PART A (2 MARKS) 1. Write the types
More informationModeling of Contact Interfaces in Built-up Structures by Zero-thickness Elements
Modeling of Contact Interfaces in Built-up Structures by Zero-thickness Elements Professor Lothar Gaul 1, Dr. Michael Mayer 2 1 University of Stuttgart, Institute of Applied and Experimental Mechanics,
More informationA 3 D finite element model for sound transmission through a double plate system with isotropic elastic porous materials
Acoustics and Vibrations Group Université de Sherbrooke, QC CANADA Département génie mécanique Université de Sherbrooke Sherbrooke, QC CANADA Tel.: (819) 821-7157 Fax: (819) 821-7163 A 3 D finite element
More informationApplication of LS-DYNA to NVH Solutions in the Automotive Industry
14 th International LS-DYNA Users Conference Session: Simulation Application of LS-DYNA to NVH Solutions in the Automotive Industry Prasanna S. Kondapalli, Tyler Jankowiak BASF Corp., Wyandotte, MI, U.S.A
More informationThe sound power output of a monopole source in a cylindrical pipe containing area discontinuities
The sound power output of a monopole source in a cylindrical pipe containing area discontinuities Wenbo Duan, Ray Kirby To cite this version: Wenbo Duan, Ray Kirby. The sound power output of a monopole
More informationExample-3. Title. Description. Cylindrical Hole in an Infinite Mohr-Coulomb Medium
Example-3 Title Cylindrical Hole in an Infinite Mohr-Coulomb Medium Description The problem concerns the determination of stresses and displacements for the case of a cylindrical hole in an infinite elasto-plastic
More informationA HIGHER-ORDER BEAM THEORY FOR COMPOSITE BOX BEAMS
A HIGHER-ORDER BEAM THEORY FOR COMPOSITE BOX BEAMS A. Kroker, W. Becker TU Darmstadt, Department of Mechanical Engineering, Chair of Structural Mechanics Hochschulstr. 1, D-64289 Darmstadt, Germany kroker@mechanik.tu-darmstadt.de,
More informationCode_Aster. SDLS07 - Clean modes of an envelope spherical thin
Titre : SDLS07 - Modes propres d'une enveloppe sphérique m[...] Date : 28/07/2015 Page : 1/13 SDLS07 - Clean modes of an envelope spherical thin Summary: This test from guide VPCS makes it possible to
More informationSound Attenuation by Hearing Aid Earmold Tubing
Excerpt from the Proceedings of the COMSOL Conference 2008 Hannover Sound Attenuation by Hearing Aid Earmold Tubing Mads J. Herring Jensen Widex A/S Ny Vestergaardsvej 19, DK-3500 Vaerloese, Denmark, mjj@widex.dk
More informationCalculation of sound radiation in infinite domain using a meshless method
PROCEEDINGS of the 22 nd International Congress on Acoustics Structural Acoustics and Vibration: Paper ICA2016-41 Calculation of sound radiation in infinite domain using a meshless method Shaowei Wu (a),
More informationActive Integral Vibration Control of Elastic Bodies
Applied and Computational Mechanics 2 (2008) 379 388 Active Integral Vibration Control of Elastic Bodies M. Smrž a,m.valášek a, a Faculty of Mechanical Engineering, CTU in Prague, Karlovo nam. 13, 121
More informationSpatio-Temporal Characterization of Bio-acoustic Scatterers in Complex Media
DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Spatio-Temporal Characterization of Bio-acoustic Scatterers in Complex Media Karim G. Sabra, School of Mechanical Engineering,
More informationAGH University of Science and Technology, Poland. Cracow University of Technology, Poland
Numerical and experimental analysis of the effectiveness of material composition of piezoelectric elements with chosen shapes on plate vibration reduction Jerzy WICIAK 1 ; Roman TROJANOWSKI 2 ; Margareta
More informationTransactions on Modelling and Simulation vol 8, 1994 WIT Press, ISSN X
Model analysis of plates using the dual reciprocity boundary element method T.W. Davies & F.A. Moslehy Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida,
More informationThe Rotating Inhomogeneous Elastic Cylinders of. Variable-Thickness and Density
Applied Mathematics & Information Sciences 23 2008, 237 257 An International Journal c 2008 Dixie W Publishing Corporation, U. S. A. The Rotating Inhomogeneous Elastic Cylinders of Variable-Thickness and
More informationSound Radiation Of Cast Iron
Purdue University Purdue e-pubs International Compressor Engineering Conference School of Mechanical Engineering 2002 Sound Radiation Of Cast Iron N. I. Dreiman Tecumseh Products Company Follow this and
More informationGeneral elastic beam with an elastic foundation
General elastic beam with an elastic foundation Figure 1 shows a beam-column on an elastic foundation. The beam is connected to a continuous series of foundation springs. The other end of the foundation
More informationThe sound generated by a transverse impact of a ball on a circular
J. Acoust. Soc. Jpn. (E) 1, 2 (1980) The sound generated by a transverse impact of a ball on a circular plate Toshio Takahagi*, Masayuki Yokoi*, and Mikio Nakai** *Junior College of Osaka Industrial University,
More informationCHAPTER 5 SIMULATION OF A PAYLOAD FAIRING
CHAPTER 5 SIMULATION OF A PAYLOAD FAIRING In the preceding chapters, a model of a PZT actuator exciting a SS cylinder has been presented. The structural model is based on a modal expansion formulation
More informationNumerical simulation on ground vibration caused by the demolition of a 200 m high chimney
Numerical simulation on ground vibration caused by the demolition of a 2 m high chimney Wenming Jiang 1, Feng Lin 2 Department of Structural Engineering, Tongji University, Shanghai, China 2 Corresponding
More informationGuided convected acoustic wave coupled with a membrane wall used as noise reduction device
Buenos Aires 5 to 9 September, 016 Acoustics for the 1 st Century PROCEEDINGS of the nd International Congress on Acoustics Structural Acoustics and Vibration (others): Paper ICA016-516 Guided convected
More informationPrediction of Light Rail Vehicle Noise in Running Condition using SEA
Prediction of Light Rail Vehicle Noise in Running Condition using SEA Sebastian PREIS ; Gérard BORELLO Siemens AG Austria Urban Transport, Austria InterAC, France ABSTRACT A complete Light Rail vehicle
More informationA numerical model for ground-borne vibrations from underground railway traffic based on a periodic FE-BE formulation
A numerical model for ground-borne vibrations from underground railway traffic based on a periodic FE-BE formulation D. Clouteau, R. Othman, M. Arnst, H. Chebli Ecole Centrale de Paris, LMSSMat, F-99 Chˆatenay-Malabry,
More informationTransactions on Engineering Sciences vol 14, 1997 WIT Press, ISSN
On the Computation of Elastic Elastic Rolling Contact using Adaptive Finite Element Techniques B. Zastrau^, U. Nackenhorst*,J. Jarewski^ ^Institute of Mechanics and Informatics, Technical University Dresden,
More informationIdentifying Dynamic Characteristics of the Traction Motor Housing for the Noise Reduction of the Electric Vehicle
EVS28 KINTEX, Korea, May 3-6, 2015 Identifying Dynamic Characteristics of the Traction Motor Housing for the Noise Reduction of the Electric Vehicle Jongchan Park 1, Seungyong Park 1 Electric Power Engineering
More informationThis is the author s version of a work that was submitted/accepted for publication in the following source:
This is the author s version of a work that was submitted/accepted for publication in the following source: Lin, Tian Ran & Pan, Jie (29) Sound radiation characteristics of a box-type structure. Journal
More informationTransactions on Modelling and Simulation vol 12, 1996 WIT Press, ISSN X
Field reconstruction by acoustic holography technique based on BEM Y.A. He, Z.Y. He Acoustic Engineering Institute, Harbin Engineering University, Harbin, Heilongjiang 150001, China Abstract This paper
More information