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E-raamat: GETMe Mesh Smoothing Framework: A Geometric Way to Quality Finite Element Meshes [Taylor & Francis e-raamat]

(NIKI Digital Engineering, Greece and TWT GmbH Science and Innovation, Germany),
  • Formaat: 254 pages, 22 Tables, black and white; 112 Illustrations, black and white
  • Ilmumisaeg: 03-Dec-2018
  • Kirjastus: CRC Press
  • ISBN-13: 9780429399626
Teised raamatud teemal:
  • Taylor & Francis e-raamat
  • Hind: 170,80 €*
  • * hind, mis tagab piiramatu üheaegsete kasutajate arvuga ligipääsu piiramatuks ajaks
  • Tavahind: 244,00 €
  • Säästad 30%
  • Formaat: 254 pages, 22 Tables, black and white; 112 Illustrations, black and white
  • Ilmumisaeg: 03-Dec-2018
  • Kirjastus: CRC Press
  • ISBN-13: 9780429399626
Teised raamatud teemal:
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.
1 Introduction
1(6)
2 Elements and meshes
7(16)
2.1 Elements
7(3)
2.1.1 Elements for planar and surface meshes
7(1)
2.1.2 Elements for volumetric meshes
8(2)
2.2 Meshes
10(3)
2.2.1 Introduction
10(1)
2.2.2 Mesh types
11(2)
2.3 Quality criteria
13(5)
2.3.1 Introduction
13(1)
2.3.2 The mean ratio quality criterion
14(3)
2.3.3 Mesh quality numbers
17(1)
2.4 Mesh generation
18(5)
2.4.1 Overview
18(2)
2.4.2 Delaunay meshes
20(3)
3 The finite element method
23(20)
3.1 History of the finite element method
23(2)
3.2 Fundamentals
25(12)
3.2.1 Elliptical boundary value problems
25(2)
3.2.2 Sobolev spaces
27(2)
3.2.3 Variational formulation
29(3)
3.2.4 Ritz-Galerkin method
32(2)
3.2.5 Linear trial functions over triangular elements
34(3)
3.3 Influence of mesh quality on solution accuracy
37(6)
4 Mesh improvement
43(10)
4.1 Overview and classification
43(4)
4.2 Mesh smoothing
47(3)
4.2.1 Laplacian smoothing and its variants
47(2)
4.2.2 Global optimization
49(1)
4.3 Topological modifications
50(3)
4.3.1 Template-based improvement
50(2)
4.3.2 Node insertion and removal
52(1)
5 Regularizing element transformations
53(56)
5.1 Transformation of polygonal elements
53(39)
5.1.1 Classic polygon transformations
53(3)
5.1.2 Generalized regularizing polygon transformations
56(31)
5.1.3 Customized polygon transformations
87(5)
5.2 Transformation of polyhedral elements
92(17)
5.2.1 Opposite face normals-based transformations
92(4)
5.2.2 Dual element-based transformations
96(13)
6 The GETMe smoothing framework
109(42)
6.1 Building blocks of the GETMe framework
109(13)
6.1.1 Basic GETMe simultaneous smoothing
109(6)
6.1.2 GETMe simultaneous smoothing
115(4)
6.1.3 GETMe sequential smoothing
119(3)
6.2 Combined GETMe algorithms
122(7)
6.2.1 GETMe smoothing
122(1)
6.2.2 Adaptive GETMe smoothing
123(6)
6.3 Properties of GETMe smoothing
129(9)
6.3.1 Influence of transformation parameters
129(3)
6.3.2 Influence of initial mesh validity and quality
132(3)
6.3.3 Unrestricted surface mesh smoothing
135(3)
6.4 Extending the GETMe mesh improvement framework
138(13)
6.4.1 Surface mesh smoothing
139(2)
6.4.2 Anisotropic mesh smoothing
141(4)
6.4.3 Combining GETMe with topology modification
145(4)
6.4.4 Using GETMe for mesh untangling
149(2)
7 Numerical examples
151(68)
7.1 Polygonal meshes
151(17)
7.1.1 Mixed planar mesh
151(5)
7.1.2 Single element type surface meshes
156(5)
7.1.3 Anisotropic meshes
161(7)
7.2 Single element type volumetric meshes
168(14)
7.2.1 Tetrahedral meshes
168(5)
7.2.2 Hexahedral meshes
173(9)
7.3 Mixed element type volumetric meshes
182(10)
7.3.1 Embedded meshes
182(6)
7.3.2 Layered mesh
188(4)
7.4 Finite element method results
192(27)
7.4.1 Model problem and error norms
192(2)
7.4.2 Planar example
194(12)
7.4.3 Volumetric example
206(13)
8 Extending the GETMe smoothing framework
219(16)
8.1 Alternative element transformations
219(13)
8.1.1 Flotation-based transformations
219(4)
8.1.2 Geometric transformations with non-regular limits
223(3)
8.1.3 Gradient flow
226(6)
8.2 Variations of GETMe smoothing
232(3)
8.2.1 Geometric triangle transformation-based smoothing
232(1)
8.2.2 GETOpt
233(2)
Bibliography 235(14)
Index 249
Dr. Dimitris Vartziotis studied Aeronautical and Space Engineering (MSc) (Prof. John

Argyris) and Civil Engineering (MSc). He carried out his PhD Thesis in Computational

Mechanics. He worked as a scientific executive in IBM Germany. He founded and

manages the companies and TWT GmbH. TWT GmbH has been awarded

first place for innovation and overall evaluation amongst the top German automotive

companies. His research focuses on scientific technology and theoretical Mathematics.

He publishes in international scientific journals of publishing houses such as Elsevier

and Springer. Moreover, he is a reviewer for the European Mathematical Society

(zbMATH) and the American Mathematical Society (AMS).

Dr. Joachim Wipper studied mathematics and computer sciences with an emphasis on

numerical mathematics and computer aided geometric design. From 1999 he worked as

scientific employee at the Mathematical Institute of Stuttgart University and earned his

doctorate degree in 2005 working on a spline based finite element method. In 2006 he

changed to TWT GmbH Science & Innovation working on industrial and research

projects covering engineering and mathematical topics. Since 2013 he is employed in

the Research & Development department of TRUMPF Werkzeugmaschinen GmbH &

Co. KG.