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COMBINED delaunay triangulation AND ADAPTIVE FINITE ELEMENT METHOD FOR CRACK GROWTH ANALYSIS

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Acta Mechanica Sinica 2003年第2期19卷 162-171页

作者： PramoteDECHAUMPHAI SutthisakPHONGTHANAPANICH ThanawatSRICHAROENCHAI MechanicalEngineeringDepartment ChulalongkornUniversityBangkok10330Thailand1 MechanicalEngineeringDepartment ChulalongkornUniversityBangkok10330Thailand

The paper presents the utilization of the adaptive delaunay triangulation in the finite element modeling of two dimensional crack propagation problems, including detailed description of the proposed procedure which consists of the delaunay triangulation algorithm and an adaptive remeshing technique. The adaptive remeshing technique generates small elements around crack tips and large elements in the other regions. The resulting stress intensity factors and simulated crack propagation behavior are used to evaluate the effectiveness of the procedure. Three sample problems of a center cracked plate, a single edge cracked plate and a compact tension specimen, are simulated and their results assessed.

关键词： delaunay triangulation adaptive mesh finite element method stress intensity factors crack propagation

A combined contour lines iteration algorithm and delaunay triangulation for terrain modeling enhancement

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Geo-Spatial Information Science 2023年第3期26卷 558-576页

作者： Yehia Miky Abdullah Kamel Ahmed Alshouny Department of Geomatics King Abdul aziz UniversityJeddahSaudi Arabia Faculty of Engineering Aswan UniversityAswanEgypt National Water Research Center Survey Research InstituteGizaEgypt

Digital Elevation Models(DEMs)play a crucial role in civil and environmental applications,such as hydrologic and geologic analyses,hazard monitoring,natural resources exploration,***,DEMs can be generated from various data sources,such as ground surveys,photogrammetric stereo methods,satellite images,laser scanning,and digitized contour *** with other data sources,contour lines are still the cheapest and more common data source becausethey cover all areas,at different scales,in most *** there are different algorithms and technologies for interpolation in between contour lines,DEMs extracted solely from contours still suffer from poor terrain quality representation,which in turn negatively affects the quality of analytical applications *** this paper,an approach for improving the digital terrain modeling based on contour line densification and delaunay triangulation is presented to acquire a more suitable DEM for hydrographic modeling and its *** proposed methodology was tested using a variety of terrain patterns in terms of intensity:hilly,undulated,and plain(1:25,000 topographic map,5 m contour interval).The precision of the extracted GRID model increases as the number of added contours *** four contour lines,the Root Mean Square Error(RMSE)of examining points were 0.26 m,0.29 m,and 0.05 m for hilly,undulated,and plain samples,respectively,and the Mean Absolute Error(MAE)were 0.50 m,0.48 m,and 0.17 *** convergence probabilities between extracted and original flow lines for the same regions were 96.91%,94.93%,and 84.03%.Applying the methodology,experimental results indicate that the developed approach provides a significant advantage in terrain modeling enhancement,generates DEMs smoothly and effectively from contours,mitigates problems and reduces uncertainties.

关键词： Contours Digital Elevation Model(DEM) Triangulated Irregular Network(TIN) delaunay triangulation

ADAPTIVE delaunay triangulation WITH MULTIDIMENSIONAL DISSIPATION SCHEME FOR HIGH-SPEED COMPRESSIBLE FLOW ANALYSIS

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Applied Mathematics and Mechanics(English Edition) 2005年第10期26卷 1341-1356页

作者： P.Dechaumphai S.Phongthanapanich Mechanical Engineering Department Chulalongkorn University Bangkok 10330 ThailandMechanical Engineering Department Chulalongkorn University Bangkok 10330 Thailand

Adaptive delaunay triangulation is combined with the cell-centered upwinding algorithm to analyze inviscid high-speed compressible flow problems. The multidimensional dissipation scheme was developed and included in the upwinding algorithm for unstructured triangular meshes to improve the computed shock wave resolution. The solution accuracy is further improved by coupling an error estimation procedure to a remeshing algorithm that generates small elements in regions with large change of solution gradients, and at the same time, larger elements in other regions. The proposed scheme is further extended to achieve higher-order spatial and temporal solution accuracy. Efficiency of the combined procedure is evaluated by analyzing supersonic shocks and shock propagation behaviors for both the steady and unsteady high-speed compressible flows.

关键词： adaptive meth movement delaunay triangulation cell-centered upwinding high-speed compressible flow

delaunay triangulation AND IMAGE DENSE MATCHING IN VIEW SYNTHESIS

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Chinese Journal of Aeronautics 1999年第3期12卷 45-49页

作者：沈沛意王伟吴成柯西安电子科技大学信息工程系综合业务网理论及关键技术国家重点实验室陕西西安

A new method of view synthesis is proposed based on delaunay triangulation. The first step of this method is making the delaunay triangulation of 2 reference images. Secondly, matching the image points using the epipolar geometry constraint. Finally, constructing the third view according to pixel transferring under the trilinear constraint. The method gets rid of the classic time consuming dense matching technique and takes advantage of delaunay triangulation. So it can not only save the computation time but also enhance the quality of the synthesized view. The significance of this method is that it can be used directly in the fields of video coding, image compressing and virtual reality.

关键词： view synthesis delaunay triangulation image matching pixel transferring

Redesign of a conformal boundary recovery algorithm for 3D delaunay triangulation

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第12期7卷 2031-2042页

作者： CHEN Jian-jun ZHENG Yao Center for Engineering and Scientific Computation School of Computer Science Zhejiang University Hangzhou 310027 China

Boundary recovery is one of the main obstacles in applying the delaunay criterion to mesh generation. A stan- dard resolution is to add Steiner points directly at the intersection positions between missing boundaries and triangulations. We redesign the algorithm with the aid of some new concepts, data structures and operations, which make its implementation routine. Furthermore, all possible intersection cases and their solutions are presented, some of which are seldom discussed in the litera- ture. Finally, numerical results are presented to evaluate the performance of the new algorithm.

关键词： Boundary recovery delaunay triangulation Mesh generation Data structure

Complex conforming delaunay triangulation

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Science China(Information Sciences) 2010年第6期53卷 1130-1140页

作者： MENG XianHai 1, LI JiGang 1, YANG Qin 1, CAI Qiang 2 & CHEN QiMing 3 1 NLSDE, School of Computer Science and Engineering, BeiHang University, Beijing 100083, China 2 School of Computer Sciences, Beijing Technology and Business University, Beijing 100037, China 3 School of Mechanical Engineering and Automation, BeiHang University, Beijing 100083, China NLSDE School of Computer Science and Engineering BeiHang University Beijing China School of Computer Sciences Beijing Technology and Business University Beijing China School of Mechanical Engineering and Automation BeiHang University Beijing China

A novel algorithm of conforming delaunay triangulation for curved geometry is presented in the paper.A progress has been made for the problem puzzled delaunay refinement where curved constraints cannot be accepted as input *** algorithm is based on a new sufficient condition for the existence of constraints in *** requires computing only the intersection between constraints and Voronoi edges or faces instead of the circum-sphere of curved *** the termination of the algorithm when small input angles exist in constraints, a weighted method is applied to ensure that the algorithm can terminate under any *** two-dimensional and three-dimensional results are also *** is shown that the algorithm has the capability of dealing with both linear and nonlinear constraints in a consistent way, without the need of maintaining triangular meshes on face constraints.

关键词： mesh generation delaunay triangulation conforming curved constraints tetrahedralization weight

Formation Optimization Of RoboCup3D Soccer Robots Using delaunay triangulation Network

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Formation Optimization Of RoboCup3D Soccer Robots Using Dela...

IMPROVED delaunay triangulation FOR TRIMMED NURBS SURFACE

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作者： Keji He Zhiwei Liang Tongxin Cui Zhiying Ke Zichang Liu Qian Zhao Fang Fang College of Automation Nanjing University of Posts and Telecommunications

In RoboCup3D robot simulation platform,team collaboration plays an important role in order to win a *** paper proposes a novel method of team formation ***,the delaunay triangulation method is applied to divide the football field into small triangular ***,the SBSP mechanism for the team is employed to choose a reasonable ***,the Linear interpolation method is used to calculate robots’ positions in different formations with data set given *** a result,the team can get the most optimal formation for the football in different *** experimental results demonstrate the effectiveness of our methods.

关键词： RoboCup Soccer robots delaunay triangulation SBSP mechanism Formation design Linear interpolation method

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Transactions of Nanjing University of Aeronautics and Astronautics 2004年第2期21卷 98-105页

作者： SUNKe-hao CollegeofAerospaceEngineering NUAA29YudaoStreetNanjing210016P.R.China

An improved algorithm of delaunay triangulation is proposed by expanding the scope from a convex polygon to an arbitrary polygon area in which holes can be contained in the subdivision procedure. The data structure of generated triangles and the exuviationslike method play a key role, and a single connectivity domain (SCD) without holes is constructed as the initial part of the algorithm. Meanwhile, some examples show that the method can be applied to the triangulation of the trimmed NURBS surface. The result of surface tessellation can be used in many applications such as NC machining, finite element analysis, rendering and mechanism interference detection.

关键词： delaunay triangulation trimmed NURBS surface polygon single connectivity domain

OPTIMAL delaunay triangulationS

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Journal of Computational Mathematics 2004年第2期22卷 299-308页

作者： LongChen Jin-chaoXu MathematicsDepartment ThePennsylvaniaStateUniversityUniversityParkPA16802USA

The delaunay triangulation, in both classic and more generalized sense, is studied in this paper for minimizing the linear interpolation error (measure in L^P-norm) for a given function. The classic delaunay triangulation can then be characterized as an optimal triangulation that minimizes the interpolation error for the isotropic function ‖x‖^2 among all the triangulations with a given set of vertices. For a more general function, a functiondependent delaunay triangulation is then defined to be an optimal triangulation that minimizes the interpolation error for this function and its construction can be obtained by a simple lifting and projection procedure. The optimal delaunay triangulation is the one that minimizes the interpolation error among all triangulations with the same number of vertices, i.e. the distribution of vertices are optimized in order to minimize the interpolation error. Such a function-depend entoptimal delaunay triangulation is proved to exist for any given convex continuous *** an optimal delaunay triangulation associated with f, it is proved that △↓f at the interior vertices can be exactly recovered by the function values on its neighboring *** the optimal delaunay triangulation is difficult to obtain in practice, the concept of nearly optimal triangulation is introduced and two sufficient conditions are presented for a triangulation to be nearly optimal.

关键词： delaunay triangulation Anisotropic mesh generation N term approximation Interpolation error Mesh quality Finite element