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 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 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 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 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 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 The GETMe Mesh Smoothing Framework written by Dimitris P. Vartziotis and published by CRC Press. This book was released on 2018-12-07 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: High quality meshes play a key role in many applications based on digital modeling and simulation. The finite element method is a paragon for such an approach and it is well known that quality meshes can significantly improve computational efficiency and solution accuracy of this method. Therefore, a lot of effort has been put in methods for improving mesh quality. These range from simple geometric approaches, like Laplacian smoothing, with a high computational efficiency but possible low resulting mesh quality, to global optimization-based methods, resulting in an excellent mesh quality at the cost of an increased computational and implementational complexity. The geometric element transformation method (GETMe) aims to fill the gap between these two approaches. It is based on geometric mesh element transformations, which iteratively transform polygonal and polyhedral elements into their regular counterparts or into elements with a prescribed shape. GETMe combines a Laplacian smoothing-like computational efficiency with a global optimization-like effectiveness. The method is straightforward to implement and its variants can also be used to improve tangled and anisotropic meshes. This book describes the mathematical theory of geometric element transformations as foundation for mesh smoothing. It gives a thorough introduction to GETMe-based mesh smoothing and its algorithms providing a framework to focus on effectively improving key mesh quality aspects. It addresses the improvement of planar, surface, volumetric, mixed, isotropic, and anisotropic meshes and addresses aspects of combining mesh smoothing with topological mesh modification. The advantages of GETMe-based mesh smoothing are demonstrated by the example of various numerical tests. These include smoothing of real world meshes from engineering applications as well as smoothing of synthetic meshes for demonstrating key aspects of GETMe-based mesh improvement. Results are compared with those of other smoothing methods in terms of runtime behavior, mesh quality, and resulting finite element solution efficiency and accuracy. Features: • Helps to improve finite element mesh quality by applying geometry-driven mesh smoothing approaches. • Supports the reader in understanding and implementing GETMe-based mesh smoothing. • Discusses aspects and properties of GETMe smoothing variants and thus provides guidance for choosing the appropriate mesh improvement algorithm. • Addresses smoothing of various mesh types: planar, surface, volumetric, isotropic, anisotropic, non-mixed, and mixed. • Provides and analyzes geometric element transformations for polygonal and polyhedral elements with regular and non-regular limits. • Includes a broad range of numerical examples and compares results with those of other smoothing methods.

Download or read book Assessment Metrics and Techniques for Hexahedral Finite Element Mesh Generation written by David R. White and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Automatic Mesh Generation written by Paul L. George and published by . This book was released on 1991 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Arbitrary 2 element H coarsening of a TTH generated Hexahedral FEA Mesh microform written by Sándor D. Kostya and published by Library and Archives Canada = Bibliothèque et Archives Canada. This book was released on 2005 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hybrid Particle element Method for a General Hexahedral Mesh written by Roque Julio Hernandez and published by . This book was released on 2009 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of improved numerical methods for computer simulation of high velocity impact dynamics is of importance in a variety of science and engineering fields. The growth of computing capabilities has created a demand for improved parallel algorithms for high velocity impact modeling. In addition, there are selected impact applications where experimentation is very costly, or even impossible (e.g. when certain bioimpact or space debris problems are of interest). This dissertation extends significantly the class of problems where particle-element based impact simulation techniques may be effectively applied in engineering design. This dissertation develops a hybrid particle-finite element method for a general hexahedral mesh. This work included the formulation of a numerical algorithm for the generation of an ellipsoidal particle set for an unstructured hex mesh, and a new interpolation kernel for the density. The discrete model is constructed using thermomechanical Lagrange equations. The formulation is validated via simulation of published impact experiments.

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 Connectivity based All hexahedral Mesh Generation Method and Apparatus written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present invention is a computer-based method and apparatus for constructing all-hexahedral finite element meshes for finite element analysis. The present invention begins with a three-dimensional geometry and an all-quadrilateral surface mesh, then constructs hexahedral element connectivity from the outer boundary inward, and then resolves invalid connectivity. The result of the present invention is a complete representation of hex mesh connectivity only; actual mesh node locations are determined later. The basic method of the present invention comprises the step of forming hexahedral elements by making crossings of entities referred to as "whisker chords." This step, combined with a seaming operation in space, is shown to be sufficient for meshing simple block problems. Entities that appear when meshing more complex geometries, namely blind chords, merged sheets, and self-intersecting chords, are described. A method for detecting invalid connectivity in space, based on repeated edges, is also described, along with its application to various cases of invalid connectivity introduced and resolved by the method.

Download or read book Hexahedral Mesh Generation from Volumetric Data by Dual Interval Volume written by Fei Xiao and published by . This book was released on 2018 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finite element methods play an important role in the field of scientific research and engineering applications. An important requirement of numerical methods is to discretize the model into a mesh composed of simple elements. In three-dimensional numerical analysis, tetrahedral and hexahedral elements are usually used. Tetrahedral meshes have the advantage of high efficiency, easy implementation, flexibility for adaptive mesh generation and (relatively) easy mesh regeneration. However, hexahedral meshes have an advantage over tetrahedron element meshes regarding the analysis accuracy and total number of elements. This makes hexahedral meshes an attractive choice for numerical analysis. In medical and industrial applications, X-ray computed tomography (CT) or magnetic resonance imaging (MRI) scanners are widely used in medical and industrial diagnostics. The CT and MRI produce a regular grid with scalar values at each grid vertex. This regular grid is called volumetric data. Hexahedral mesh generation for volumetric data provides an opportunity to exploit the structure provided in the volumetric data.

Download or read book Seawater Intrusion in Coastal Aquifers written by Jacob Bear and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coastal aquifers serve as major sources for freshwater supply in many countries around the world, especially in arid and semi-arid zones. Many coastal areas are also heavily urbanized, a fact that makes the need for freshwater even more acute. Coastal aquifers are highly sensitive to disturbances. Inappropriate management of a coastal aquifer may lead to its destruction as a source for freshwater much earlier than other aquifers which are not connected to the sea. The reason is the threat of seawater intrusion. In many coastal aquifers, intrusion of seawater has become one of the major constraints imposed on groundwater utilization. As sea water intrusion progresses, existing pumping wells, especially those close to the coast, become saline and have to be abandoned. Also, the area above the intruding seawater wedge is lost as a source of natural replenishment to the aquifer. Despite the importance of this subject, so far there does not exist a book that integrates our present knowledge of seawater intrusion, its occurrences, physical mechanism, chemistry, exploration by geo physical and geochemical techniques, conceptual and mathematical modeling, analytical and numerical solution methods, engineering measures of combating seawater intrusion, management strategies, and experience learned from case studies. By presenting this fairly comprehensive volume on the state-of-the-art of knowledge and ex perience on saltwater intrusion, we hoped to transfer this body of knowledge to the geologists, hydrologists, hydraulic engineers, water resources planners, managers, and governmental policy makers, who are engaged in the sustainable development of coastal fresh ground water resources.

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 Solder Joint Reliability written by John H. Lau and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 649 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solders have given the designer of modern consumer, commercial, and military electronic systems a remarkable flexibility to interconnect electronic components. The properties of solder have facilitated broad assembly choices that have fueled creative applications to advance technology. Solder is the electrical and me chanical "glue" of electronic assemblies. This pervasive dependency on solder has stimulated new interest in applica tions as well as a more concerted effort to better understand materials properties. We need not look far to see solder being used to interconnect ever finer geo metries. Assembly of micropassive discrete devices that are hardly visible to the unaided eye, of silicon chips directly to ceramic and plastic substrates, and of very fine peripheral leaded packages constitute a few of solder's uses. There has been a marked increase in university research related to solder. New electronic packaging centers stimulate applications, and materials engineering and science departments have demonstrated a new vigor to improve both the materials and our understanding of them. Industrial research and development continues to stimulate new application, and refreshing new packaging ideas are emerging. New handbooks have been published to help both the neophyte and seasoned packaging engineer.