Download or read book Quadrilateral hexahedral Finite Element Mesh Coarsening written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A technique for coarsening a finite element mesh ("FEM") is described. This technique includes identifying a coarsening region within the FEM to be coarsened. Perimeter chords running along perimeter boundaries of the coarsening region are identified. The perimeter chords are redirected to create an adaptive chord separating the coarsening region from a remainder of the FEM. The adaptive chord runs through mesh elements residing along the perimeter boundaries of the coarsening region. The adaptive chord is then extracted to coarsen the FEM.
Download or read book Quadrilateral Finite Element Mesh Coarsening written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Techniques for coarsening a quadrilateral mesh are described. These techniques include identifying a coarsening region within the quadrilateral mesh to be coarsened. Quadrilateral elements along a path through the coarsening region are removed. Node pairs along opposite sides of the path are identified. The node pairs along the path are then merged to collapse the path.
Download or read book Hexahedral Finite Element Mesh Coarsening Using Pillowing Technique written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A techniques for coarsening a hexahedral mesh is described. The technique includes identifying a coarsening region within a hexahedral mesh to be coarsened. A boundary sheet of hexahedral elements is inserted into the hexahedral mesh around the coarsening region. A column of hexahedral elements is identified within the boundary sheet. The column of hexahedral elements is collapsed to create an extraction sheet of hexahedral elements contained within the coarsening region. Then, the extraction sheet of hexahedral elements is extracted to coarsen the hexahedral mesh.
Download or read book Quadrilateral Hexahedral Mesh Coarsening written by and published by . This book was released on 2006 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Localized Coarsening of Conforming All hexahedral Meshes written by Adam C. Woodbury and published by . This book was released on 2008 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finite element mesh adaptation methods can be used to improve the efficiency and accuracy of solutions to computational modeling problems. For many finite element modeling applications, a conforming all-hexahedral mesh is preferred. When adapting a hexahedral mesh, localized modifications that preserve topologic conformity are often desired. Effective hexahedral refinement methods that satisfy these criteria have recently become available. However, due to hexahedral mesh topology constraints, little progress has been made in the area of hexahedral coarsening. This thesis presents a new method to locally coarsen conforming all-hexahedral meshes. The method works on both structured and unstructured meshes and is not based on undoing previous refinement. Building upon recent developments in quadrilateral coarsening, the method utilizes hexahedral sheet and column operations, including pillowing, column collapsing, and sheet extraction. A general algorithm for automated coarsening is presented and examples of models that have been coarsened are shown. While results are promising, further work is needed to improve the automated process.
Download or read book Proceedings of the 17th International Meshing Roundtable written by Rao V. Garimella and published by Springer Science & Business Media. This book was released on 2008-10-23 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the articles presented at the 17th International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and held October 12-15, 2008. The volume presents recent results of mesh generation and adaptation which has applications to finite element simulation. It introduces theoretical and novel ideas with practical potential.
Download or read book Finite Element Mesh Generation written by Daniel S.H. Lo and published by CRC Press. This book was released on 2015-01-15 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highlights the Progression of Meshing Technologies and Their Applications Finite Element Mesh Generation provides a concise and comprehensive guide to the application of finite element mesh generation over 2D domains, curved surfaces, and 3D space. Organised according to the geometry and dimension of the problem domains, it develops from the basic meshing algorithms to the most advanced schemes to deal with problems with specific requirements such as boundary conformity, adaptive and anisotropic elements, shape qualities, and mesh optimization. It sets out the fundamentals of popular techniques, including: Delaunay triangulation Advancing-front (ADF) approach Quadtree/Octree techniques Refinement and optimization-based strategies From the geometrical and the topological aspects and their associated operations and inter-relationships, each approach is vividly described and illustrated with examples. Beyond the algorithms, the book also explores the practice of using metric tensor and surface curvatures for generating anisotropic meshes on parametric space. It presents results from research including 3D anisotropic meshing, mesh generation over unbounded domains, meshing by means of intersection, re-meshing by Delaunay-ADF approach, mesh refinement and optimization, generation of hexahedral meshes, and large scale and parallel meshing, along with innovative unpublished meshing methods. The author provides illustrations of major meshing algorithms, pseudo codes, and programming codes in C++ or FORTRAN. Geared toward research centers, universities, and engineering companies, Finite Element Mesh Generation describes mesh generation methods and fundamental techniques, and also serves as a valuable reference for laymen and experts alike.
Download or read book Automated All quadrilateral Mesh Adaptation Through Refinement and Coarsening written by Bret Dallas Anderson and published by . This book was released on 2009 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a new approach to conformal all-quadrilateral mesh adaptation. In finite element modeling applications, it is often desirable to modify the node density of the mesh; increasing the density in some parts of the mesh to provide more accurate results, while decreasing the density in other parts to reduce computation time. The desired node density is typically determined by a sizing function based on either the geometry of the model or the results of a finite element solution. Although there are numerous mesh adaptation methods currently in use, including initial adaptive mesh generation, node redistribution, and adaptive mesh refinement, there are relatively few methods that modify the mesh density by adding and removing mesh elements, and none of these guarantee a conformal, all-quadrilateral mesh while allowing general coarsening. This work introduces a new method that incorporates both conformal refinement and coarsening strategies on an existing mesh of any density or configuration. Given a sizing function, this method modifies the mesh by combining existing template based quadrilateral refinement methods with recent developments in localized quadrilateral coarsening and quality improvement into an automated mesh adaptation routine.
Download or read book Automated Quadrilateral Coarsening by Ring Collapse written by Mark William Dewey and published by . This book was released on 2008 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: In most finite element analysis, a uniform mesh is not the optimum way to model the problem. Mesh adaptation is the ability to modify a finite element model to include regions of the mesh with higher and lower node density. Mesh adaptation has received extensive study in both computational mechanics and computer graphics to increase the resolution or accuracy of the solution in specific areas. The algorithm developed in this thesis, the Automated Quadrilateral Coarsening by Ring Collapse (AQCRC) algorithm, provides a unique solution to allow conformal coarsening of both structured and unstructured quadrilateral finite element meshes. The algorithm is based on dual chord operations and dual chord removal. The AQCRC algorithm follows six steps: 1) input of a coarsening region and factor, 2) selection of coarsening rings, 3) improvement of mesh quality, 4) removal of coarsening rings, 5) mesh clean-up and 6) coarsening iterations. Examples are presented that show the application of the algorithm.
Download or read book Proceedings of the 18th International Meshing Roundtable written by Brett W. Clark and published by Springer Science & Business Media. This book was released on 2009-11-26 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the articles presented at the 18th International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and held October 25-28, 2009 in Salt Lake City, Utah, USA. The volume presents recent results of mesh generation and adaptation which has applications to finite element simulation. It introduces theoretical and novel ideas with practical potential.
Download or read book Using Conjoint Meshing Primitives to Generate Quadrilateral and Hexahedral Elements in Irregular Regions written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The parameter-space mapping technique used in most finite element mesh generation programs requires that the geometry be subdivided into either rectangular areas in 2-D or rectilinear volumes in 3-D to produce, respectively, quadrilateral or hexahedral elements. Since subdivision occurs in parameter space, the edges bounding the areas and volumes need not be straight or parallel lines. Simple geometries may be subdivided easily while irregular features challenge the analyst. This paper presents the formulation and application of conjoint meshing primitives that assist the analyst in meshing in and around irregular features. The term conjoint is applied to these primitives because each is composed of several rectangular areas or rectilinear volumes. Interval assignments may vary from side to side, within a set of constraints, for each primitive. Thus, all of them are useful for transitions between other regular areas or volumes. In 2-D, the primitive areas are the triangle, pentagon, semi-circle, circle, and rectangular transition. These primitives are implemented in the Sandia meshing program FASTQ and are used in regular production work. They are also the basis for decomposition regions in the developing artificial intelligence Automated Meshing Knowledge System, AMEKS. In 3-D, the primitive volumes are the 2-D primitives extended in depth together with the tetrahedon and two rectilinear transition volumes. These primitives are the foundation for extending AMEKS to 3-D. 9 refs., 14 figs.
Download or read book The Definition and Extraction of Shape Abstractions for Automatic Finite Element Hexahedral Mesh Generation written by Shang-Sheng Liu and published by . This book was released on 1997 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mixed finite element Method on Hexahedral Meshes written by Jielin Xu and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we have three goals. The first goal is to investigate the accuracy behavior due to lumping procedure. The second goal is to investigate the effects of different boundary partitions of macro-cells. The last goal is to numerically verify the error estimate proposed by Kuznetsov in 2011. In the first part, we propose a new mixed-finite-element approximation method, elaborate its construction and discretization. We, afterwards, propose a new procedure called “coarsening of fluxes” or “lumping” procedure which will impose only one degree of freedom for flux on each quadrilateral face instead of two under admissible conditions. In the second part, we first derive the optimal boundary partitions for both non-degenerate and degenerate groups. The thesis also introduces two center-based interior partitions which have been widely used nowadays, and we conclude that the optimal boundary partitions discovered in thesis reduce huge amounts of elimination work compared with two center-based interior partitions. We also propose a homogenization procedure which introduce one degree of freedom for solution function in each macro-cell. Finally, the results of numerical experiments demonstrate that with lumping procedure, the errors do not converge to zero, instead they will stay stagnant asymptotically as we refine the mesh.
Download or read book Hexahedral Mesh Refinement Using an Error Sizing Function written by Gaurab Paudel and published by . This book was released on 2011 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to effectively adapt a mesh is a very important feature of high fidelity finite element modeling. In a finite element analysis, a relatively high node density is desired in areas of the model where there are high error estimates from an initial analysis. Providing a higher node density in such areas improves the accuracy of the model and reduces the computational time compared to having a high node density over the entire model. Node densities can be determined for any model using the sizing functions based on the geometry of the model or the error estimates from the finite element analysis. Robust methods for mesh adaptation using sizing functions are available for refining triangular, tetrahedral, and quadrilateral elements. However, little work has been published for adaptively refining all hexahedral meshes using sizing functions. This thesis describes a new approach to drive hexahedral refinement based upon an error sizing function and a mechanism to compare the sizes of the node after refinement.
Download or read book Thinking Modally written by Elena Domínguez and published by Cambridge Scholars Publishing. This book was released on 2015-10-28 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume brings together a selection of the papers presented at the 4th International Conference on Modality in English, held in Madrid on 9–11 September 2010. The book is divided into two parts, with the first encompassing contributions focusing on the notions of modality, evidentiality and temporality, and the second those that explore modality and its connection with stance and evaluation in specific genres and discourse domains.
Download or read book Proceedings of the 16th International Meshing Roundtable written by Michael L. Brewer and published by Springer Science & Business Media. This book was released on 2007-10-01 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the articles presented at the 16th International Meshing Roundtable (IMR) organized, in part, by Sandia National Laboratories and held in Seattle, Washington, U.S.A. in October, 2007. The volume presents recent results of mesh generation and adaptation which has applications to finite element simulation. It introduces theoretical and novel ideas with practical potential.
Download or read book Accuracy Verification Methods written by Olli Mali and published by Springer Science & Business Media. This book was released on 2013-10-27 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of accuracy verification methods was understood at the very beginning of the development of numerical analysis. Recent decades have seen a rapid growth of results related to adaptive numerical methods and a posteriori estimates. However, in this important area there often exists a noticeable gap between mathematicians creating the theory and researchers developing applied algorithms that could be used in engineering and scientific computations for guaranteed and efficient error control. The goals of the book are to (1) give a transparent explanation of the underlying mathematical theory in a style accessible not only to advanced numerical analysts but also to engineers and students; (2) present detailed step-by-step algorithms that follow from a theory; (3) discuss their advantages and drawbacks, areas of applicability, give recommendations and examples.
