AUTOMATED ALL-QUADRILATERAL MESH ADAPTATION THROUGH REFINEMENT AND COARSENING Bret Dallas Anderso... more AUTOMATED ALL-QUADRILATERAL MESH ADAPTATION THROUGH REFINEMENT AND COARSENING Bret Dallas Anderson Department of Civil and Environmental Engineering Master of Science 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 wh...
Modern computer-aided applications (CAx) like computer-aided design (CAD), computer-aided enginee... more Modern computer-aided applications (CAx) like computer-aided design (CAD), computer-aided engineering (CAE) and computer-aided manufacturing (CAM) assign engineering models to one technical person; i.e. a designer, analyst, or a process planner. Collaboration is limited to interactive design sessions, serial model sharing, terminal/screen sharing, and to conference call interactions. Current CAx tools do not permit simultaneous model changes by a collaborative team working on the same model. This paper considers CAx architectural changes that allow product teams to concurrently and simultaneously collaborate and modify product models. Early prototypes also expose current CAx collaborative and architectural deficiencies.
Computer Methods in Applied Mechanics and Engineering, 1982
Abstract Computer graphics is proving to be an increasingly useful tool in helping the analyst to... more Abstract Computer graphics is proving to be an increasingly useful tool in helping the analyst to fully appreciate pattern information contained within the results of nonlinear calculations. This paper reviews the applications of a general purpose computer graphics system, called MOVIE.BYU, to the display of the results of a wide range of static and dynamic nonlinear finite element analyses. These results are presented in line drawing and continuous tone image format. They display sophisticated problems in geotechnical engineering, nonlinear fracture mechanics, material failure, and finite deformation of elastic plastic materials.
... Effective use of the method was enhanced with the introduction of low cost computer ... 5. Fu... more ... Effective use of the method was enhanced with the introduction of low cost computer ... 5. Future issues Future developments in both hardware and software will provide enhancements of ... Preprocessing Development of user friendly geometric modeling will continue to be a major ...
... Element Meshes for Elastic and Elasto-plastic Analysis Steven E. Benzley, Ernest Perry, Karl ... more ... Element Meshes for Elastic and Elasto-plastic Analysis Steven E. Benzley, Ernest Perry, Karl Merkley, Brett Clark Brigham Young University Provo, Utah Greg Sjaardama Sandia National Laboratories Albuquerque, NM. ABSTRACT ...
Elementary Engineering Mechanics classes (i.e. Statics, Dynamics, and Mechanics of Materials) pro... more Elementary Engineering Mechanics classes (i.e. Statics, Dynamics, and Mechanics of Materials) provide an integral portion of lower division engineering curricula for Civil, Mechanical, and Manufacturing Engineering. These courses are crucial in the engineering education process for these disciplines because they introduce students to the engineering approach in problem solving, provide basic principles that are used in following courses, and let lower division students recognize if they are equipped for an engineering curricula. In addition, many questions for the Fundamentals of Engineering exam have their roots in these courses. Providing the proper teaching environment for these courses is a challenge for faculty and department administrations because a) there are numerous students that must be accommodated, b) the students deserve a quality experience to both introduce them to the engineering curriculum and to give them a positive encounter in the major, and c) the content of th...
Certain applications of the finite element method require hexahedral meshes for the underlying di... more Certain applications of the finite element method require hexahedral meshes for the underlying discretization. A procedure, known as THexing, which is guaranteed to produce an all-hex mesh is to begin with a tetrahedral mesh and then subdivide each element into four hexahedra. This research presents a method for improving the THex approach, known as Diced THexing, or DTHexing. The DTHex approach is based on general coarsening tools. An initial triangle surface mesh is coarsened and smoothed iteratively until a coarse mesh of reasonable quality is obtained. The volume is then easily meshed using a tetrahedral scheme, then refined using ’h’ type modifications. The goal of this method is to 1) improve the quality of elements in the finite element mesh and 2) decrease the number of overall nodes. The DTHex approach has been successful at improving models on biological meshes without increasing node count. This research was conducted using the CUBIT software.
High fidelity finite element modeling of continuum mechanics problems often requires using all qu... more High fidelity finite element modeling of continuum mechanics problems often requires using all quadrilateral or all hexahedral meshes. The efficiency of such models is often dependent upon the ability to adapt a mesh to the physics of the phenomena. Adapting a mesh requires the ability to both refine and/or coarsen the mesh. The algorithms available to refine and coarsen triangular
ABSTRACT This paper introduces the spatial twist continuum (STC), a powerful extension of the dua... more ABSTRACT This paper introduces the spatial twist continuum (STC), a powerful extension of the dual of a hexahedral mesh. The STC captures the global connectivity constraints inherent in hexahedral meshing. We begin by describing the two-dimensional analog of the representation for quadrilateral meshes: The STC of a quadrilateral mesh is an arrangement of curves called chords. Chords pass through opposite quadrilateral edges and intersect at quadrilateral centroids. The power of the STC is displayed in the three-dimensional representation, where continuous surfaces called twist planes pass through layers of hexahedra. Pairs of twist planes intersect to form chords that pass through opposite faces of hexahedra. Triples of twist planes orthogonally intersect at the centroids of hexahedra. The continuity of the twist planes and chords, and how twist planes and chords twist through space in tandem, are the basis of the spatial twist continuum. 1. Introduction The demand for fully automated meshing ...
Tension and compression tests on notched cylindrical bars made of 7075-T6 aluminum have been cond... more Tension and compression tests on notched cylindrical bars made of 7075-T6 aluminum have been conducted as a part of an investigation of the mechanics of ductile fracture. The compression tests showed significantly stiffer behavior in the nonlinear portion of the experiment than those found from the tension tests. This difference was accounted for by incorporating a hydrostatic stress dependent yield
AUTOMATED ALL-QUADRILATERAL MESH ADAPTATION THROUGH REFINEMENT AND COARSENING Bret Dallas Anderso... more AUTOMATED ALL-QUADRILATERAL MESH ADAPTATION THROUGH REFINEMENT AND COARSENING Bret Dallas Anderson Department of Civil and Environmental Engineering Master of Science 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 wh...
Modern computer-aided applications (CAx) like computer-aided design (CAD), computer-aided enginee... more Modern computer-aided applications (CAx) like computer-aided design (CAD), computer-aided engineering (CAE) and computer-aided manufacturing (CAM) assign engineering models to one technical person; i.e. a designer, analyst, or a process planner. Collaboration is limited to interactive design sessions, serial model sharing, terminal/screen sharing, and to conference call interactions. Current CAx tools do not permit simultaneous model changes by a collaborative team working on the same model. This paper considers CAx architectural changes that allow product teams to concurrently and simultaneously collaborate and modify product models. Early prototypes also expose current CAx collaborative and architectural deficiencies.
Computer Methods in Applied Mechanics and Engineering, 1982
Abstract Computer graphics is proving to be an increasingly useful tool in helping the analyst to... more Abstract Computer graphics is proving to be an increasingly useful tool in helping the analyst to fully appreciate pattern information contained within the results of nonlinear calculations. This paper reviews the applications of a general purpose computer graphics system, called MOVIE.BYU, to the display of the results of a wide range of static and dynamic nonlinear finite element analyses. These results are presented in line drawing and continuous tone image format. They display sophisticated problems in geotechnical engineering, nonlinear fracture mechanics, material failure, and finite deformation of elastic plastic materials.
... Effective use of the method was enhanced with the introduction of low cost computer ... 5. Fu... more ... Effective use of the method was enhanced with the introduction of low cost computer ... 5. Future issues Future developments in both hardware and software will provide enhancements of ... Preprocessing Development of user friendly geometric modeling will continue to be a major ...
... Element Meshes for Elastic and Elasto-plastic Analysis Steven E. Benzley, Ernest Perry, Karl ... more ... Element Meshes for Elastic and Elasto-plastic Analysis Steven E. Benzley, Ernest Perry, Karl Merkley, Brett Clark Brigham Young University Provo, Utah Greg Sjaardama Sandia National Laboratories Albuquerque, NM. ABSTRACT ...
Elementary Engineering Mechanics classes (i.e. Statics, Dynamics, and Mechanics of Materials) pro... more Elementary Engineering Mechanics classes (i.e. Statics, Dynamics, and Mechanics of Materials) provide an integral portion of lower division engineering curricula for Civil, Mechanical, and Manufacturing Engineering. These courses are crucial in the engineering education process for these disciplines because they introduce students to the engineering approach in problem solving, provide basic principles that are used in following courses, and let lower division students recognize if they are equipped for an engineering curricula. In addition, many questions for the Fundamentals of Engineering exam have their roots in these courses. Providing the proper teaching environment for these courses is a challenge for faculty and department administrations because a) there are numerous students that must be accommodated, b) the students deserve a quality experience to both introduce them to the engineering curriculum and to give them a positive encounter in the major, and c) the content of th...
Certain applications of the finite element method require hexahedral meshes for the underlying di... more Certain applications of the finite element method require hexahedral meshes for the underlying discretization. A procedure, known as THexing, which is guaranteed to produce an all-hex mesh is to begin with a tetrahedral mesh and then subdivide each element into four hexahedra. This research presents a method for improving the THex approach, known as Diced THexing, or DTHexing. The DTHex approach is based on general coarsening tools. An initial triangle surface mesh is coarsened and smoothed iteratively until a coarse mesh of reasonable quality is obtained. The volume is then easily meshed using a tetrahedral scheme, then refined using ’h’ type modifications. The goal of this method is to 1) improve the quality of elements in the finite element mesh and 2) decrease the number of overall nodes. The DTHex approach has been successful at improving models on biological meshes without increasing node count. This research was conducted using the CUBIT software.
High fidelity finite element modeling of continuum mechanics problems often requires using all qu... more High fidelity finite element modeling of continuum mechanics problems often requires using all quadrilateral or all hexahedral meshes. The efficiency of such models is often dependent upon the ability to adapt a mesh to the physics of the phenomena. Adapting a mesh requires the ability to both refine and/or coarsen the mesh. The algorithms available to refine and coarsen triangular
ABSTRACT This paper introduces the spatial twist continuum (STC), a powerful extension of the dua... more ABSTRACT This paper introduces the spatial twist continuum (STC), a powerful extension of the dual of a hexahedral mesh. The STC captures the global connectivity constraints inherent in hexahedral meshing. We begin by describing the two-dimensional analog of the representation for quadrilateral meshes: The STC of a quadrilateral mesh is an arrangement of curves called chords. Chords pass through opposite quadrilateral edges and intersect at quadrilateral centroids. The power of the STC is displayed in the three-dimensional representation, where continuous surfaces called twist planes pass through layers of hexahedra. Pairs of twist planes intersect to form chords that pass through opposite faces of hexahedra. Triples of twist planes orthogonally intersect at the centroids of hexahedra. The continuity of the twist planes and chords, and how twist planes and chords twist through space in tandem, are the basis of the spatial twist continuum. 1. Introduction The demand for fully automated meshing ...
Tension and compression tests on notched cylindrical bars made of 7075-T6 aluminum have been cond... more Tension and compression tests on notched cylindrical bars made of 7075-T6 aluminum have been conducted as a part of an investigation of the mechanics of ductile fracture. The compression tests showed significantly stiffer behavior in the nonlinear portion of the experiment than those found from the tension tests. This difference was accounted for by incorporating a hydrostatic stress dependent yield
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