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Kathy Loeppky
Conference Coordinator

kloeppk@sandia.gov
(505) 844-2376



Short Courses

The IMR short courses will be held Sunday, October 11, 2015. Courses are taught by internationally known experts in the field of Mesh Generation. Each course is an hour and a half in length including breaks. Instructors will address practical issues in the design and implementation of both structured and unstructured mesh generation codes.

These courses are ideal for students just entering the field who may need a foundation for research as well as any seasoned professionals who would like to expand their current skill set in the development of mesh and grid generation algorithms. To register for the short courses, mark the appropriate boxes on the registration form.



Instructors



Instructor Bios and Course Abstracts

Dr. Jonathan Shewchuk, University of California, Berkeley

Title: Tetrahedral Mesh Improvement and Dynamic Meshing

Biography: Jonathan Shewchuk is a Professor in the Department of Electrical Engineering and Computer Sciences at the University of California at Berkeley. He is best known for his software Triangle for high-quality triangular mesh generation, which won the 2003 James Hardy Wilkinson Prize in Numerical Software, and his "Introduction to the Conjugate Gradient Method Without the Agonizing Pain."

The tetrahedral mesh improvement program Stellar, coauthored by Bryan Klingner, Martin Wicke, and Pascal Clausen and discussed in this talk, is freely available to the public at http://www.cs.berkeley.edu/~jrs/stellar/ .

Abstract: This short course is an introduction to algorithms for improving the quality of tetrahedral meshes. These algorithms are used as a "post-processing" step that takes meshes generated by traditional mesh generation algorithms (such as advancing front, Delaunay, octree-based, and particle/bubble meshing methods) and improves them by locally replacing small groups of tetrahedra with other tetrahedra having better quality or more appropriate sizes. Although mesh improvement methods do not replace traditional mesh generation algorithms (because the former require the latter to generate an initial mesh from an input geometry), they have become powerful enough to achieve substantially better mesh quality than the traditional methods can obtain unassisted.

Topics covered include topological transformations such as bistellar flips, "edge removals", edge contractions, and vertex insertions; algorithms for computing optimal versions of some of these transformations; optimization-based mesh smoothing (i.e., the numerical optimization of vertex positions); and schedules for attempting to apply mesh transformations. The course ends with a brief discussion of how mesh improvement methods can be used in dynamic meshing, where meshes change shape through time to track deforming materials.



Yongjie Jessica Zhang, Carnegie Mellon University

Title: Image-Based Mesh Generation and Volumetric T-Spline Modeling for Isogeometric Analysis

Biography: Yongjie Jessica Zhang is an Associate Professor in Mechanical Engineering at Carnegie Mellon University with a courtesy appointment in Biomedical Engineering. She received her B.Eng. in Automotive Engineering, and M.Eng. in Engineering Mechanics, all from Tsinghua University, China, and M.Eng. in Aerospace Engineering and Engineering Mechanics, and Ph.D. in Computational Engineering and Sciences from the University of Texas at Austin. Her research interests include computational geometry, mesh generation, computer graphics, visualization, finite element method, isogeometric analysis and their application in computational biomedicine, material sciences and engineering. She has co-authored over 100 publications in peer-reviewed journals and conference proceedings. She is the recipient of Presidential Early Career Award for Scientists and Engineers, NSF CAREER Award, Office of Naval Research Young Investigator Award, USACM Gallagher Young Investigator Award, Clarence H. Adamson Career Faculty Fellow in Mechanical Engineering, George Tallman Ladd Research Award, and Donald L. & Rhonda Struminger Faculty Fellow.

Abstract: With finite element method and scanning technology seeing increased use in many research areas, there is an emerging need for high-fidelity geometric modeling and mesh generation of spatially realistic domains. In this short course, I will highlight our research in three areas: image-based mesh generation for complicated domains, trivariate spline modeling for isogeometric analysis, as well as biomedical, material sciences and engineering applications. I will first present advances and challenges in image-based geometric modeling and meshing along with a comprehensive computational framework, which integrates image processing, geometric modeling, mesh generation and quality improvement with multi-scale analysis at molecular, cellular, tissue and organ scales. Different from other existing methods, the presented framework supports five unique features: high-fidelity meshing for heterogeneous domains with topology ambiguity resolved; multiscale geometric modeling for biomolecular complexes; automatic all-hexahedral mesh generation with sharp feature preservation; robust quality improvement for non-manifold meshes; and guaranteed-quality meshing. These unique capabilities enable accurate, stable, and efficient mechanics calculation for many biomedicine, materials science and engineering applications.

In the second part of this short course, I will show our latest research on volumetric spline parameterization, which contributes directly to the integration of design and analysis, the root idea of isogeometric analysis. For arbitrary topology objects, we first build a polycube whose topology is equivalent to the input geometry and it serves as the parametric domain for the following trivariate T-spline construction. Boolean operations and geometry skeleton can also be used to preserve surface features. A parametric mapping is then used to build a one-to-one correspondence between the input geometry and the polycube boundary. After that, we choose the deformed octree subdivision of the polycube as the initial T-mesh, and make it valid through pillowing, quality improvement, and applying templates or truncation mechanism couple with subdivision to handle extraordinary nodes. The parametric mapping method has been further extended to conformal solid T-spline construction with the input surface parameterization preserved and trimming curves handled.



Dr. John A. Verdicchio, Cambridge Flow Solutions

Title: Commercial Mesh Generation – Why it’s Different to Being at a University

Biography: John Verdicchio is a software developer for Cambridge Flow Solutions and has worked there for 4 years where he is primarily involved in algorithm development. He previously worked at Rolls-Royce plc for 22 years, for the last 4 years he was responsible for the mesh generation section of a Rolls-Royce in-house code. He obtained a mathematics degree from Cambridge University (UK), a Masters in Numerical Analysis from Oxford University (UK) and his DPhil from the University of Sussex (UK). Previous to these years of developing code he has been an end user of in-house and commercial mesh generators.

Abstract: This short course looks at commercial software development with regard to mesh generation. It considers the potential differences between writing software in a university and in a commercial environment. Some of these issues are:

  • Dealing with users, customer support, documentation, access to restricted material
  • Support of operating systems, hardware platforms, compilers and licensing
  • Code version control, team developing
  • Testing
  • Data input and export of meshes
  • GUI development or not
  • Speed and robustness of code
  • The salesmen and the customer
  • Different development methodologies


Dr. Matt Staten, Sandia National Laboratories

Title: Introduction to Quadrilateral and Hexahedral Mesh Generation and Modification

Biography: Matt Staten is currently a researcher and software developer at Sandia National Laboratories and has been a member of the CUBIT development team for the past 11 years. Prior to working at Sandia, Matt gained commercial software experience working at Ansys (1996-1999) developing the Ansys 5.X and DesignSpace products, and also at Unigraphics Solutions (1999-2004) developing the NX product. Matt's primary research interest is in quadrilateral and hexahedral mesh generation and modification, with special interest in sheet/chord-based mesh modification techniques. Matt graduated from Brigham Young University in 1996 with a BS and MS in Civil Engineering, and received his PhD in Computational Science and Engineering from Carnegie Mellon University in 2010. Matt served on the IMR organizing committee from 1999-2001 and again from 2011-2014, serving as Conference Chairman in 2014 for the 23rd IMR.

Abstract: This short course reviews the theory and application of quadrilateral and hexahedral mesh generation. We first define the use cases for hex meshing over traditional tetrahedral methods and why the general all-hex problem is fundamentally more difficult. Beginning with basic transfinite interpolation methods and exploring various advancing front and overlay grid approaches we will describe a wide range of all-hex methods currently in use today. We will also review mesh modification and improvement strategies for all-hex meshes including topology operations, smoothing, refinement and coarsening. More recent research strategies that utilize dual-based technologies, frame fields and parallel methods will also be discussed.


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