共查询到20条相似文献，搜索用时 0 毫秒
1.
Alexander A. Shostko Rainald Lhner William C. Sandberg 《International journal for numerical methods in engineering》1999,44(9):1359-1376
A method for the rapid construction of meshes over intersecting triangulated shapes is described. The method is based on an algorithm that automatically generates a surface mesh from intersecting triangulated surfaces by means of Boolean intersection/union operations. After the intersection of individual components is obtained, the exposed surface parts are extracted. The algorithm is intended for rapid interactive construction of non‐trivial surfaces in engineering design, manufacturing, visualization and molecular modelling applications. Techniques to make the method fast and general are described. The proposed algorithm is demonstrated on a number of examples, including intersections of multiple spheres, planes and general engineering shapes, as well as generation of surface and volume meshes around clusters of intersecting components followed by the computation of flow field parameters. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
2.
A. Rassineux 《International journal for numerical methods in engineering》1998,41(4):651-674
An algorithm for tetrahedron mesh generation and optimization with respect to a shape and a size criterion is presented. A well distributed set of nodes is first generated by an octree method, and the set is then triangulated. The advancing front technique is used to mesh the whole volume. Emphasis has been placed on management of the front. The method involves priority construction of enhanced quality tetrahedra. Each face is assigned to a front corresponding to the quality of the best tetrahedron which can be constructed. Elements are destroyed in the case of non-convergence. Optimization procedures make local use of the algorithm used to mesh the complete model. Industrial examples of relatively complex volumes are given, demonstrating that a high quality and optimized mesh can be obtained by the proposed method. © 1998 John Wiley & Sons, Ltd. 相似文献
3.
Peter Mller Peter Hansbo 《International journal for numerical methods in engineering》1995,38(21):3551-3569
This paper deals with some aspects of unstructured mesh generation in three dimensions by the advancing front technique. In particular, the parameters used in the algorithm are characterized, and strategies that may be used to improve robustness are suggested. We also describe a method whereby structured tetrahedral meshes with exceptionally stretched elements adjacent to boundary surfaces may be produced. The suggested method can be combined with the advancing front concept in a natural way. 相似文献
4.
Y. K. Lee C. K. Lee 《International journal for numerical methods in engineering》2002,53(12):2673-2700
A new algorithm for constructing full quadrilateral anisotropic meshes on 3D surfaces is proposed in this paper. The proposed method is based on the advancing front and the systemic merging techniques. Full quadrilateral meshes are constructed by systemically converting triangular elements in the background meshes into quadrilateral elements.By using the metric specifications to describe the element characteristics, the proposed algorithm is applicable to convert both isotropic and anisotropic triangular meshes into full quadrilateral meshes. Special techniques for generating anisotropic quadrilaterals such as new selection criteria of base segment for merging, new approaches for the modifications of the background mesh and construction of quadrilateral elements, are investigated and proposed in this study. Since the final quadrilateral mesh is constructed from a background triangular mesh and the merging procedure is carried out in the parametric space, the mesh generator is robust and no expensive geometrical computation that is commonly associated with direct quadrilateral mesh generation schemes is needed. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
5.
针对大规模网格串行生成的时间和内存瓶颈问题,阐述了一种非结构化四面体网格并行生成方法,首先对几何体进行初始网格划分,并通过相对体积比及最优分区控制初始网格数量;然后采用图论图划分方法对初始网格进行区域分解;最后采用分裂法进行并行网格生成。提出的基于共享单元的边界判定方法,有效地解决了分区边界节点的匹配问题。通过算例证明了该并行网格生成方法具有良好的并行效率,同时可以产生高质量的四面体网格。 相似文献
6.
Habeun Choi Heng Chi Kyoungsoo Park Glaucio H. Paulino 《International journal for numerical methods in engineering》2021,122(1):25-52
To consistently coarsen arbitrary unstructured meshes, a computational morphogenesis process is built in conjunction with a numerical method of choice, such as the virtual element method with adaptive meshing. The morphogenesis procedure is performed by clustering elements based on a posteriori error estimation. Additionally, an edge straightening scheme is introduced to reduce the number of nodes and improve accuracy of solutions. The adaptive morphogenesis can be recursively conducted regardless of element type and mesh generation counting. To handle mesh modification events during the morphogenesis, a topology-based data structure is employed, which provides adjacent information on unstructured meshes. Numerical results demonstrate that the adaptive mesh morphogenesis effectively handles mesh coarsening for arbitrarily shaped elements while capturing problematic regions such as those with sharp gradients or singularity. 相似文献
7.
Woo‐Young Choi Dae‐Young Kwak Il‐Heon Son Yong‐Taek Im 《International journal for numerical methods in engineering》2003,58(12):1857-1872
In recent years, demand for three‐dimensional simulations has continued to grow in the field of computer‐aided engineering. Especially, in the analysis of forming processes a fully automatic and robust mesh generator is necessary for handling complex geometries used in industry. For three‐dimensional analyses, tetrahedral elements are commonly used due to the advantage in dealing with such geometries. In this study, the advancing front technique has been implemented and modified using an optimization scheme. In this optimization scheme, the distortion metric determines ‘when and where’ to smooth, and serves as an objective function. As a result, the performance of the advancing front technique is improved in terms of mesh quality generated. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
8.
Matthew L. Staten Robert A. Kerr Steven J. Owen Ted D. Blacker Marco Stupazzini Kenji Shimada 《International journal for numerical methods in engineering》2010,81(2):135-171
The generation of all‐hexahedral finite element meshes has been an area of ongoing research for the past two decades and remains an open problem. Unconstrained plastering is a new method for generating all‐hexahedral finite element meshes on arbitrary volumetric geometries. Starting from an unmeshed volume boundary, unconstrained plastering generates the interior mesh topology without the constraints of a pre‐defined boundary mesh. Using advancing fronts, unconstrained plastering forms partially defined hexahedral dual sheets by decomposing the geometry into simple shapes, each of which can be meshed with simple meshing primitives. By breaking from the tradition of previous advancing‐front algorithms, which start from pre‐meshed boundary surfaces, unconstrained plastering demonstrates that for the tested geometries, high quality, boundary aligned, orientation insensitive, all‐hexahedral meshes can be generated automatically without pre‐meshing the boundary. Examples are given for meshes from both solid mechanics and geotechnical applications. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
S. J. Owen M. L. Staten S. A. Canann S. Saigal 《International journal for numerical methods in engineering》1999,44(9):1317-1340
Q‐Morph is a new algorithm for generating all‐quadrilateral meshes on bounded three‐dimensional surfaces. After first triangulating the surface, the triangles are systematically transformed to create an all‐quadrilateral mesh. An advancing front algorithm determines the sequence of triangle transformations. Quadrilaterals are formed by using existing edges in the triangulation, by inserting additional nodes, or by performing local transformations to the triangles. A method typically used for recovering the boundary of a Delaunay mesh is used on interior triangles to recover quadrilateral edges. Any number of triangles may be merged to form a single quadrilateral. Topological clean‐up and smoothing are used to improve final element quality. Q‐Morph generates well‐aligned rows of quadrilaterals parallel to the boundary of the domain while maintaining a limited number of irregular internal nodes. The proposed method also offers the advantage of avoiding expensive intersection calculations commonly associated with advancing front procedures. A series of examples of Q‐Morph meshes are also presented to demonstrate the versatility of the proposed method. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
10.
11.
O. HASSAN K. MORGAN E. J. PROBERT J. PERAIRE 《International journal for numerical methods in engineering》1996,39(4):549-567
A method of generating general tetrahedral meshes suitable for use in viscous flow simulations is proposed. The approach which is followed consists of the initial generation of a number of unstructured layers of highly stretched elements, in the vicinity of solid walls, followed by the discretisation of the remainder of the domain, by a standard advancing front procedure. The numerical performance of the proposed methodology is demonstrated by the generation of meshes suitable for viscous flow analysis over a number of three-dimensional aerodynamic configurations of current practical interest. 相似文献
12.
R. Aubry G. Houzeaux M. Vázquez 《International journal for numerical methods in engineering》2011,85(12):1475-1498
A method is presented to remesh three‐dimensional discrete data surfaces. The originality of the method resides in mimicking heavily the classical adva10ncing front method for quality while always relying on a valid mesh for robustness. Therefore, local operations are applied in a first step to obtain a mesh of appropriate length scale compared to the specified size, and an original procedure has been developed for refinement that automatically degenerates to a surface mesh optimization if the size map has been respected. A valid mesh is then always available during the remeshing procedure. A new background grid is proposed that relies on a Cartesian mesh for the size distribution. Interpolation is performed very quickly and the size distribution is smoothed out to provide a slowly varying mesh size distribution. Various numerical results are presented to illustrate the efficiency but mainly the quality and robustness of the method. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
13.
Patrick M. Knupp 《International journal for numerical methods in engineering》2000,48(3):401-420
Structured mesh quality optimization methods are extended to optimization of unstructured triangular, quadrilateral, and mixed finite element meshes. New interpretations of well‐known nodally based objective functions are made possible using matrices and matrix norms. The matrix perspective also suggests several new objective functions. Particularly significant is the interpretation of the Oddy metric and the smoothness objective functions in terms of the condition number of the metric tensor and Jacobian matrix, respectively. Objective functions are grouped according to dimensionality to form weighted combinations. A simple unconstrained local optimum is computed using a modified Newton iteration. The optimization approach was implemented in the CUBIT mesh generation code and tested on several problems. Results were compared against several standard element‐based quality measures to demonstrate that good mesh quality can be achieved with nodally based objective functions. Published in 2000 by John Wiley & Sons, Ltd. 相似文献
14.
Josep Sarrate Antonio Huerta 《International journal for numerical methods in engineering》2000,49(10):1327-1350
15.
Daniel W. Zaide Carl F. Ollivier‐Gooch 《International journal for numerical methods in engineering》2016,106(6):484-500
In this work, a new method for inserting a surface as an internal boundary into an existing unstructured tetrahedral mesh is developed. The surface is discretized by initially placing vertices on its bounding curves, defining a length scale at every location on each boundary curve based on the local underlying mesh, and equidistributing length scale along these curves between vertices. The surface is then sampled based on this boundary discretization, resulting in a surface mesh spaced in a way that is consistent with the initial mesh. The new points are then inserted into the mesh, and local refinement is performed, resulting in a final mesh containing a representation of the surface while preserving mesh quality. The advantage of this algorithm over generating a new mesh from scratch is in allowing for the majority of existing simulation data to be preserved and not have to be interpolated onto the new mesh. This algorithm is demonstrated in two and three dimensions on problems with and without intersections with existing internal boundaries. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
16.
Finite element modelling of processes, where geometry of the component evolves with time, usually involves checks/computations for contact between objects. Examples of these kinds of processes are sheet forming, bulk forming (forging, extrusion, rolling), etc. In some cases, it may be acceptable not to perform any specific analysis on the dies and treat them as being rigid. In such cases, it is best to represent mesh models for the rigid objects with as few elements as possible. This significantly reduces the time spent by the solver in geometric checks for contact between objects. Hence, a module has been developed to read an existing discrete representation (mesh or STL facets) and coarsen it based on certain user specified criteria. This module can be used as a filter before running the analysis. Other benefits of using a compact mesh model to represent the rigid object include (a) reduced memory usage by the application, (b) a smaller results database, (c) faster visualization algorithms, and (d) faster transmission of mesh model data across networks. Results from the finite element analysis of a forging process, performed with a commercial solver, are presented. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
17.
A new unstructured mesh coarsening algorithm has been developed for use in conjunction with multilevel methods. The algorithm preserves geometrical and topological features of the domain, and retains a maximal independent set of interior vertices to produce good coarse mesh quality. In anisotropic meshes, vertex selection is designed to retain the structure of the anisotropic mesh while reducing cell aspect ratio. Vertices are removed incrementally by contracting edges to zero length. Each vertex is removed by contracting the edge that maximizes the minimum sine of the dihedral angles of cells affected by the edge contraction. Rarely, a vertex slated for removal from the mesh cannot be removed; the success rate for vertex removal is typically 99.9% or more. For two‐dimensional meshes, both isotropic and anisotropic, the new approach is an unqualified success, removing all rejected vertices and producing output meshes of high quality; mesh quality degrades only when most vertices lie on the boundary. Three‐dimensional isotropic meshes are also coarsened successfully, provided that there is no difficulty distinguishing corners in the geometry from coarsely‐resolved curved surfaces; sophisticated discrete computational geometry techniques appear necessary to make that distinction. Three‐dimensional anisotropic cases are still problematic because of tight constraints on legal mesh connectivity. More work is required to either improve edge contraction choices or to develop an alternative strategy for mesh coarsening for three‐dimensional anisotropic meshes. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
18.
Mesh smoothing is demonstrated to be an effective means of copying, morphing, and sweeping unstructured quadrilateral surface meshes from a source surface to a target surface. Construction of the smoother in a particular way guarantees that the target mesh will be a ‘copy’ of the source mesh, provided the boundary data of the target surface is a rigid body rotation, translation, and/or uniform scaling of the original source boundary data and provided the proper boundary node correspondence between source and target has been selected. Copying is not restricted to any particular smoother, but can be based on any locally elliptic second‐order operator. When the bounding loops are more general than rigid body transformations the method generates high‐quality, ‘morphed’ meshes. Mesh sweeping, if viewed as a morphing of the source surface to a set of target surfaces, can be effectively performed via this smoothing algorithm. Published in 1999 by John Wiley & Sons, Ltd. This article is a U.S. government work and is in the public domain in the United States. 相似文献
19.
Yasushi Ito Alan M. Shih Bharat K. Soni 《International journal for numerical methods in engineering》2009,77(13):1809-1833
An octree‐based mesh generation method is proposed to create reasonable‐quality, geometry‐adapted unstructured hexahedral meshes automatically from triangulated surface models without any sharp geometrical features. A new, easy‐to‐implement, easy‐to‐understand set of refinement templates is developed to perform local mesh refinement efficiently even for concave refinement domains without creating hanging nodes. A buffer layer is inserted on an octree core mesh to improve the mesh quality significantly. Laplacian‐like smoothing, angle‐based smoothing and local optimization‐based untangling methods are used with certain restrictions to further improve the mesh quality. Several examples are shown to demonstrate the capability of our hexahedral mesh generation method for complex geometries. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
20.
N P Weatherill 《Sadhana》1991,16(1):1-45
In recent years there has been much research activity in the field of compressible flow simulation for aerodynamic applications.
In the 1970’s and 1980’s the advances in the numerical solution of the Full Potential and Euler equations made, in principle,
the inviscid flow simulation around complex aerodynamic shapes possible. At this stage much attention was focused on methods
capable of generating meshes on which such calculations could be performed.
In this paper an overview is presented of some techniques which have been developed to generate meshes for aerospace applications.
Structured mesh generation techniques are discussed and their application to complicated shapes utilising the multiblock approach
is highlighted. Unstructured mesh generation methods are also discussed with particular emphasis given to the Delaunay triangulation
method. Finally, the advantages and disadvantages of the structured and unstructured approaches are discussed and new work
is presented which attempts to utilise both these approaches in an efficient and flexible manner.
An erratum to this article is available at . 相似文献