Abstract
In the case of very complex geometric morphology in three-dimensional (3-d) calculation regions, the subdivision of finite element meshes tends to be very difficult or even impossible. This problem was especially dominant in the element subdivision of rock blocks cut by arbitrary fracture networks. This study proposed a directed simplex subdivision method of 2- and 3-d regions which can readily subdivide a complex region and automatically adapt to arbitrary variations of region boundaries. The directed simplex was employed as finite elements for the first time. When the nodes of 2-d simplex (triangle) were connected anticlockwise and the nodes of 3-d simplex (tetrahedron) were linked by the right hand screw rule, the finite element is treated as a positive element. Otherwise, it is treated as a negative element. However, some generated elements presented superposition, which was unallowable in the normal finite element method (FEM). Therefore, the superposition principle of positive and negative finite elements was proposed. Such superposition method can transform a normal FEM mesh into a positive–negative FEM mesh with maintaining its completeness and compatibility. Finally, 1-d, 2-d, and 3-d cases were used as examples to verify the validity of the proposed method. The completeness and compatibility of the positive–negative FEM and the normal FEM are consistent. The accuracy of these two methods differs due to the difference of nodal connection relationships, node numbers, and element sizes. However, as the mesh is refined, the calculated results tend to be consistent.
Similar content being viewed by others
References
Baker TJ (1989) Automatic mesh generation for complex three-dimensional regions using a constrained Delaunay triangulation. Eng Comput 5:161–175
Boltcheva D, Yvinec M, Boissonnat J-D (2009) Feature preserving Delaunay mesh generation from 3D multi-material images. Comput Graph Forum 28(5):1455–1464
Borouchaki H, Lo SH (1995) Fast Dealunay triangulation in three dimensions. Comput Methods Appl Mech Eng 128:153–167
Cavalcante Neto JB, Wawrzynek PA, Carvalho MTM, Martha LF, Ingraffea AR (2001) An algorithm for three-dimensional mesh generation for arbitrary regions with cracks. Eng Comput 17:75–91
Chen J, Zhao D, Huang Z, Zheng Y, Gao S (2011) Three-dimensional constrained boundary recovery with an enhanced Steiner point suppression procedure. Comput Struct 89:455–466
Du Q, Wang D (2004) Boundary recovery for three dimensional conforming Delaunay triangulation. Comput Methods Appl Mech Eng 193:2547–2563
Du Q, Wang D (2005) The optimal centroidal voronoi tessellations and the Gersho’s conjecture in the three-dimensional space. Comput Math Appl 49:1355–1373
Du Q, Wang D (2006) Recent progress in robust and quality Delaunay mesh generation. J Comput Appl Math 195:8–23
Frey PJ, Borouchaki H, George P-L (1998) 3D Delaunay mesh generation coupled with an advancing-front approach. Comput Methods Appl Mech Eng 157:115–131
Ghadyani H, Sullivan J, Wu Z (2010) Boundary recovery for Delaunay tetrahedral meshes using local topological transformations. Finite Elem Anal Des 46:74–83
Jing L (2000) Block system construction for three-dimensional discrete element models of fractured rocks. Int J Rock Mech Min Sci 37(4):645–659
Jin L, Stephansson O (1994) Topological identification of block assemblages for jointed rock masses. Int J Rock Mech Min Sci 31(2):163–172
Karamete BK, Beall M, Shephard M (2000) Triangulation of arbitrary polyhedra to support automatic mesh generators. Int J Numer Methods Eng 49:167–191
Lederman C, Joshi A, Dinov I, Vese L, Toga A, Van Horn JD (2011) The generation of tetrahedral mesh models for neuroanatomical MRI. NeuroImage 55(1):153–164
Lewis RW, Zheng Y, Usmani AS (1995) Aspects of adaptive mesh generation based on domain decomposition and Delaunay triangulation. Finite Elem Anal Des 20(1):47–70
Lewis RW, Zheng Y, Gethin DT (1996) Three-dimensional unstructured mesh generation: Part 3. Volume meshes. Comput Methods Appl Mech Eng 134:285–310
Lin D, Fairhurst C, Starfield AM (1987) Geometrical identification of three-dimensional rock block systems using topological techniques. Int J Rock Mech Min Sci 24(6):331–338
Liu Y, Lo S, Guan Z, Zhang H (2014) Boundary recovery for 3D Delaunay triangulation. Finite Elem Anal Des 84:32–43
Lo SH, Wang WX (2005) Finite element mesh generation over intersecting curved surfaces by tracing of neighbours. Finite Elem Anal Des 41:351–370
Löhner R (1996) Progress in grid generation via the advancing front technique. Eng Comput 12:186–199
Radovitzky R, Ortiz M (2000) Tetrahedral mesh generation based on node insertion in crystal lattice arrangements and advancing-front-Delaunay triangulation. Comput Methods Appl Mech Eng 187:543–569
Rassineux A (1997) 3D mesh adaptation. Optimization of tetrahedral meshes by advancing front technique. Comput Methods Appl Mech Eng 141:335–354
Schroeder WJ, Shephard MS (1990) A combined Octree/Delaunay method for fully automatic 3-D mesh generation. Int J Numer Methods Eng 29(1):37–55
Secchi S, Simoni L (2003) An improved procedure for 2D unstructured Delaunay mesh generation. Adv Eng Softw 34:217–234
Shi G, Goodman RE (1989) The key blocks of unrolled joint traces in developed maps of tunnel walls. Int J Numer Anal Methods Geomech 13:131–158
Shi G (1995) Simplex integration for manifold method and discontinuous deformation analysis. In: Proceedings of the First International Conference on Analysis of Discontinuous Deformation. Chungli, Taiwan, China, pp 1–25
Shi G (2006) Producing joint polygons, cutting joint blocks and finding key blocks from general free surfaces. Chin J Rock Mech Eng 25(11):2161–2170
Tabarraei A, Sukumar N (2005) Adaptive computations on conforming quadtree meshes. Finite Elem Anal Des 41(7–8):686–702
Tian J, Jiang W, Luo T, Cai K, Peng J, Wang W (2012) Adaptive coding of generic 3D triangular meshes based on octree decomposition. Vis Comput 28:819–827
Xing H, Liu Y, 2014. Mesh Generation for 3D geological reservoirs with arbitrary stratigraphic surface constraints. In: 14th international conference on computational science, pp 897–909
Zhang Q-H, Yin J-M (2014) Solution of two key issues in arbitrary three-dimensional discrete fracture network flow models. J Hydrol 514:281–296
Zhang Q-H (2015) Advances of study on three-dimensional block cutting analysis and its application. Comput Geotech 63:26–32
Acknowledgements
This research was sponsored by the General Program of National Natural Science Foundation of China (Grant No. 51679012) and the Key Program of National Natural Science Foundation of China (Grant No. 51539002).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Zhang, QH., Su, HD. & Lin, SZ. The simplex subdivision of a complex region: a positive and negative finite element superposition principle. Engineering with Computers 34, 155–173 (2018). https://doi.org/10.1007/s00366-017-0527-9
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00366-017-0527-9