A Projection Transformation Method for Nearly Singular Surface Boundary Element Integrals

A Projection Transformation Method for Nearly Singular Surface Boundary Element Integrals

Author: Ken Hayami

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 465

ISBN-13: 364284698X

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In three dimensional boundary element analysis, computation of integrals is an important aspect since it governs the accuracy of the analysis and also because it usually takes the major part of the CPU time. The integrals which determine the influence matrices, the internal field and its gradients contain (nearly) singular kernels of order lIr a (0:= 1,2,3,4,.··) where r is the distance between the source point and the integration point on the boundary element. For planar elements, analytical integration may be possible 1,2,6. However, it is becoming increasingly important in practical boundary element codes to use curved elements, such as the isoparametric elements, to model general curved surfaces. Since analytical integration is not possible for general isoparametric curved elements, one has to rely on numerical integration. When the distance d between the source point and the element over which the integration is performed is sufficiently large compared to the element size (d> 1), the standard Gauss-Legendre quadrature formula 1,3 works efficiently. However, when the source is actually on the element (d=O), the kernel 1I~ becomes singular and the straight forward application of the Gauss-Legendre quadrature formula breaks down. These integrals will be called singular integrals. Singular integrals occur when calculating the diagonals of the influence matrices.


A Projection Transformation Method for Nearly Singular Surface Boundary Element Integrals

A Projection Transformation Method for Nearly Singular Surface Boundary Element Integrals

Author: Ken Hayami

Publisher: Springer

Published: 1992-03-30

Total Pages: 456

ISBN-13: 9783540550006

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In three dimensional boundary element analysis, computation of integrals is an important aspect since it governs the accuracy of the analysis and also because it usually takes the major part of the CPU time. The integrals which determine the influence matrices, the internal field and its gradients contain (nearly) singular kernels of order lIr a (0:= 1,2,3,4,.··) where r is the distance between the source point and the integration point on the boundary element. For planar elements, analytical integration may be possible 1,2,6. However, it is becoming increasingly important in practical boundary element codes to use curved elements, such as the isoparametric elements, to model general curved surfaces. Since analytical integration is not possible for general isoparametric curved elements, one has to rely on numerical integration. When the distance d between the source point and the element over which the integration is performed is sufficiently large compared to the element size (d> 1), the standard Gauss-Legendre quadrature formula 1,3 works efficiently. However, when the source is actually on the element (d=O), the kernel 1I~ becomes singular and the straight forward application of the Gauss-Legendre quadrature formula breaks down. These integrals will be called singular integrals. Singular integrals occur when calculating the diagonals of the influence matrices.


The Boundary Element Method, Volume 1

The Boundary Element Method, Volume 1

Author: L. C. Wrobel

Publisher: John Wiley & Sons

Published: 2002-04-22

Total Pages: 480

ISBN-13: 9780471720393

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The boundary element method (BEM) is a modern numerical techniquewhich has enjoyed increasing popularity over the last two decades,and is now an established alternative to traditional computationalmethods of engineering analysis. The main advantage of the BEM isits unique ability to provide a complete solution in terms ofboundary values only, with substantial savings in modelling effort. This two-volume book set is designed to provide the readers with acomprehensive and up-to-date account of the boundary element methodand its application to solving engineering problems. Each volume isa self-contained book including a substantial amount of materialnot previously covered by other text books on the subject. Volume 1covers applications to heat transfer, acoustics, electrochemistryand fluid mechanics problems, while volume 2 concentrates on solidsand structures, describing applications to elasticity, plasticity,elastodynamics, fracture mechanics and contact analysis. The earlychapters are designed as a teaching text for final yearundergraduate courses. Both volumes reflect the experience of theauthors over a period of more than twenty years of boundary element research. This volume, Applications in Thermo-Fluids and Acoustics, provides acomprehensive presentation of the BEM from fundamentals to advancedengineering applications and encompasses: Steady and transient heat transfer Potential and viscous fluid flows Frequency and time-domain acoustics Corrosion and other electrochemical problems. A unique feature of this book is an in-depth presentation of BEMformulations in all the above fields, including detaileddiscussions of the basic theory, numerical algorithms and practicalengineering applications of the method. Written by an internationally recognised authority in the field,this is essential reading for postgraduates, researchers andpractitioners in civil, mechanical and chemical engineering andapplied mathematics.


The Boundary Element Method, Volume 2

The Boundary Element Method, Volume 2

Author: M. H. Aliabadi

Publisher: John Wiley & Sons

Published: 2002-04-29

Total Pages: 614

ISBN-13: 9780470842980

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The boundary element method (BEM) is a modern numerical technique, which has enjoyed increasing popularity over the last two decades, and is now an established alternative to traditional computational methods of engineering analysis. The main advantage of the BEM is its unique ability to provide a complete solution in terms of boundary values only, with substantial savings in modelling effort. This two-volume book set is designed to provide the readers with a comprehensive and up-to-date account of the boundary element method and its application to solving engineering problems. Each volume is a self-contained book including a substantial amount of material not previously covered by other text books on the subject. Volume 1 covers applications to heat transfer, acoustics, electrochemistry and fluid mechanics problems, while volume 2 concentrates on solids and structures, describing applications to elasticity, plasticity, elastodynamics, fracture mechanics and contact analysis. The early chapters are designed as a teaching text for final year undergraduate courses. Both volumes reflect the experience of the authors over a period of more than twenty years of boundary element research. This volume, Applications in Solids and Structures, provides a comprehensive presentation of the BEM from fundamentals to advanced engineering applications and encompasses: Elasticity for 2D, 3D and Plates and Shells Non-linear, Transient and Thermal Stress Analysis Crack Growth and Multi-body Contact Mechanics Sensitivity Analysis and Optimisation Analysis of Assembled Structures. An important feature of this book is the in-depth presentation of BEM formulations in all the above fields, including detailed discussions of the basic theory, numerical algorithms and where possible simple examples are included, as well as test results for practical engineering applications of the method. Although most of the methods presented are the latest developments in the field, the author has included some simple techniques, which are helpful in understanding the computer implementation of BEM. Another notable feature is the comprehensive presentation of a new generation of boundary elements known as the Dual Boundary Element Method. Written by an internationally recognised authority in the field, this is essential reading for postgraduates, researchers and practitioners in Aerospace, Mechanical and Civil Engineering and Applied Mathematics.


2D/3D Boundary Element Programming in Petroleum Engineering and Geomechanics

2D/3D Boundary Element Programming in Petroleum Engineering and Geomechanics

Author: Nobuo Morita

Publisher: Elsevier

Published: 2020-11-17

Total Pages: 480

ISBN-13: 0128238399

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2D/3D Boundary Element Programming in Petroleum Engineering and Geomechanics, Volume 72, is designed to make it easy for researchers, engineers and students to begin writing boundary element programs. This reference covers the fundamentals, theoretical developments, programming and applications. Both fluid flow through porous media and structural problems are used for coding exercises. Included computer programs may be used as starting codes; after modifications, they can be applied to real world problems. The book covers topics around mesh generation, 3D boundary element coding, and interface coding for controlling mesh generation, and plotting results. - Includes interactive 2D and 3D coding exercises that readers can modify based on need - Features research on the most recent developments in indirect and dual boundary element methods - Contains case studies showing examples and applications of the theories presented in the book


Current Distributions and Electrode Shape Changes in Electrochemical Systems

Current Distributions and Electrode Shape Changes in Electrochemical Systems

Author: Johan Deconinck

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 299

ISBN-13: 3642847161

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This book reponds to the increasing demand of computer mo- delling of electrochemical processes in order to improve their speed and efficiency. The fundamental transport equa- tions in dilute solutions are given and it is established in detail under what circumstances a potential model with non- linear boundary conditions, involved by electrode reactions, can beused. Attention is directed towards the most impor- tant solution techniquesFEM, FDM and BEM and towards the solution of the non-linear system of equations (Successive Substitution, Newton-Raphson). Using the BEM, several two- dimensional and axisymmetrical examples of current density distributions are given and quantitative data, obtained in a copper electro-refining cell, are compared with calculated results. Applying Faraday's Law and the BEM, simulation of electro-deposition, electro-chemical levelling and machining are treated. Accuracy and stabilityare emphasized.


Reliability and Optimization of Structural Systems ’91

Reliability and Optimization of Structural Systems ’91

Author: Rüdiger Rackwitz

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 486

ISBN-13: 3642847536

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This proceedings volume contains 38 papers presented at the 4th Working Conference on "Rel iability· and Optimization of Structural Systems", held at the Technical University of Munich, Germany, September 11- 13, 1991. The Working Conference was organised by the IFIP (Interna tional Federation for Information Processing) Working Group 7.5 of Technical Committee 7 and was the fourth in a series, following similar conferences held at the University of Aalborg, Den mark, May 1987, at the Imperial College, London, UK, September 1988 and at the University of California, Berkeley, California, USA, March 1990. The Working Conference was attended by 54 participants from 16 countries. The objectives of Working Group 7.5 are: • to promote modern structural systems optimization and reliability theory, • to advance international cooperation in the field of structural system optimization and reliability theory, • to stimulate research, development and application of structural system optimization and reli ability theory, • to further the dissemination and exchange of information on reliability and optimization of structural systems • to encourage education in structural system optimization and reliability theory. At present the members of the Working Group are: A. H.-S. Ang, U.S.A. M. Grimmelt, FRG G. A ugwti, Italy N. C. Lind, Canada M. J. Baker, UK H. O. Mad&en, Denmark P. Bjerager, Norway R. E. Melcher~, Australia C. A. Cornell, U.S.A. F. Mo~e~, U.S.A.


Boundary Element Method XVI

Boundary Element Method XVI

Author: C. A. Brebbia

Publisher: Computational Mechanics

Published: 1994

Total Pages: 628

ISBN-13: 9781853122835

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This title contains the edited proceedings from the 16th International Conference on Boundary Element Methods, held in July 1994. The included papers consider the applications of BEM to various mechanics problems and covers the topics of diffusion, acoustics, heat transfer, inverse problems, numerical and computational aspects, adaptive techniques, stress and fracture mechanics, elastodynamics, geomechanics and coupling problems.