首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到18条相似文献,搜索用时 78 毫秒
1.
三角形网格转化为四边形网格   总被引:26,自引:4,他引:22  
现有的全自动网格划分算法大部分生成三角形网格。生成四边形网格更困难。为了缓解这个问题,本文研究并实现了三角形网格转化为四边形网格的线性算法。该算法是对已有的O(N^2)算法的改进。  相似文献   

2.
针对文献[1]中提出的四边形网格形变因子的不足,提出了曲面中改进的四边形形变因子。根据此约束条件,研究并实现了一种将3DS模型表面三角形网格转化为四边形网格的合并算法,并对极少的残余三角形进行拆分处理,实现彻底转化。经过对已有模型的实际转化实验,表明了本算法的有效性。  相似文献   

3.
四边形网格间接生成方法   总被引:1,自引:0,他引:1       下载免费PDF全文
研究了基于背景三角网格的四边形网格间接生成算法,并针对三角形合并过程中容易残留三角形的缺陷提出了确定侧边的详细算法,该算法主要是依据背景三角网格中边的位置和前沿边的情形,通过背景三角网格中已存在的边、边交换或边分割确定侧边,以避免在三角形合并过程中残留三角形单元。最后给出实例验证了算法的有效性。  相似文献   

4.
前沿法生成四边形网格的改进方法   总被引:6,自引:0,他引:6  
针对传统前沿法生成四边形网格时算法不稳定,有残余三角形等缺点,该文提出泛前沿的概念。泛前沿是对目前前沿概念的更高层次上的抽象,不但避免了前沿拆分和合并带来的不稳定,而且使得前沿操作起来更简单有效。然后文章通过消除坏四边形单元,消除残余三角形单元等操作,最终得到了质量较好的全四边形网格。最后,给出了用此法划分的例子。  相似文献   

5.
已有的四边形网格的简化及优化方法大多数都是三角形网格简化在局部几何上的推广.四边形网格的结构受螺旋条带的影响,移除四边形网格中的螺旋条带则可以在拓扑结构上明显提高四边形网格的质量.文中具体讨论了四边形网格上螺旋条带与网格上奇异点的关系及其性质,并根据这个性质给出了四边形网格中螺旋条带的一般生成算法.实验结果表明,该算法可以有效地搜索四边形网格上的螺旋条带,进而通过删除螺旋条带优化四边形网格的拓扑结构.  相似文献   

6.
以Q-Morph算法思想为基础,实现增加约束后自动生成二维域多约束四边形有限元网格.通过增加约束修补子算法,使原算法思想适用于附加的多约束;同时调整了原有算法中单元四边形顶边的生成子算法和四边形内多余三角形删除子算法的烦琐之处.实例测试结果表明,用文中算法生成的约束四边形网格具有网格分布较均匀、网格形状较规整等特点.  相似文献   

7.
四边形网格生成中的前沿边生长改进算法   总被引:1,自引:0,他引:1       下载免费PDF全文
为提高B样条曲面重构中点云四边形网格的生成效率和质量,对现有的四边形网格Q-Morph前沿边生长算法进行改进,提出面向四边形网格生成的三角网格拓扑优化方法,通过设定生长限制条件和调整网格顶点度,保证全局四边形网格质量,实现适合复杂曲面重构的规则四边形网格获取。实例结果表明,该算法效率高、适应性好,生成的四边形网格具有分布均匀、不规则网格数量少的优点。  相似文献   

8.
平面任意区域四边形网格自动生成的一种方法   总被引:9,自引:2,他引:9  
在改进节点连接法的基础上,提出了一种平面任意区域的有限元网格全自动剖分方法,既能快速生成四边形单元网格,也能生成三角形单元网格;  相似文献   

9.
文中创新地提出了三角形连接的有限元网格划分的算法,但是三角形并不是有限元计算的基本单元,而是根据已经生成的三角形生成较为规整的四边形。在实际的项目过程中,创新地提出了三种有效的算法,并利用C++面向对象的MFC程序设计和编写。本程序可以从模型文件读取边界以及点约束和线约束特征数据,程序自动计算出一个较为合理的边界间距值,并且根据需要人工或自动选择一种划分算法,从而自动完成高质量的四边形网格划分。三种算法皆可以处理大量数据点和线,并且划分速度较为高效。本程序模块成功应用于有限元计算软件中。  相似文献   

10.
分析计算有限元三角形网格顶点法矢的各种算法原理,比较各种算法的结果精度,指出Max方法考虑了三角形网格的形状,且本质上是一种通过对四面体进行外接球面拟合的计算方法,结果精度很高.在此基础上,针对曲面在有限元网格划分后可能同时存在三角形网格和四边形网格,提出适应于单独的三角形网格和四边形网格与两者并存的混合网格的顶点法矢求取算法,计算结果表明了算法的适应性和有效性.  相似文献   

11.
本文所述改进算法删除了原有算法的诸多繁琐之处,改进了原有算法的许多不足,并加入了一些新的算法规则。实例测试结果表明,用本文所述改进算法生产的四边形网格具有网格分布均匀,四格四边形接近于规则四边等特点。  相似文献   

12.
This paper describes a novel template-based meshing approach for generating good quality quadrilateral meshes from 2D digital images. This approach builds upon an existing image-based mesh generation technique called Imeshp, which enables us to create a segmented triangle mesh from an image without the need for an image segmentation step. Our approach generates a quadrilateral mesh using an indirect scheme, which converts the segmented triangle mesh created by the initial steps of the Imesh technique into a quadrilateral one. The triangle-to-quadrilateral conversion makes use of template meshes of triangles. To ensure good element quality, the conversion step is followed by a smoothing step, which is based on a new optimization-based procedure. We show several examples of meshes generated by our approach, and present a thorough experimental evaluation of the quality of the meshes given as examples.  相似文献   

13.
给定一车身冲压模型腔表面上结构化的四边形网格,通过单元合并对网格进行自动的粗化,其目的在于简化冲压仿真模型,提高仿真计算速度,首先,根据单元节点曲率半径的分布,搜寻出满足单元合并条件的初始四边形区域,接头,判断初始合交区域的边界过渡条件,最后,进行单合并,冲压成型仿真应用实例证明,文中算法既提高了仿真速度,又保持了仿真精度,该算法可以推广到任意曲面结构化四边形网格的局部粗化问题。  相似文献   

14.
Generating quadrilateral meshes is a highly non-trivial task, as design decisions are frequently driven by specific application demands. Automatic techniques can optimize objective quality metrics, such as mesh regularity, orthogonality, alignment and adaptivity; however, they cannot make subjective design decisions. There are a few quad meshing approaches that offer some mechanisms to include the user in the mesh generation process; however, these techniques either require a large amount of user interaction or do not provide necessary or easy to use inputs. Here, we propose a template-based approach for generating quad-only meshes from triangle surfaces. Our approach offers a flexible mechanism to allow external input, through the definition of alignment features that are respected during the mesh generation process. While allowing user inputs to support subjective design decisions, our approach also takes into account objective quality metrics to produce semi-regular, quad-only meshes that align well to desired surface features.  相似文献   

15.
给出一个使用覆盖栅格生成四边形网格的算法.覆盖法能够快速生成有限元网格,但是边界单元的质量通常比较差,也难以得到全部的四边形网格.将边界内角分成4类,根据不同类型的内角,提出相应的使用覆盖栅格生成完全四边形网格所要采取的修正措施.最后,应用文中算法进行网格划分,结果表明该算法是有效的.  相似文献   

16.
Certain classes of problems result in solution fields of which the characteristic length scales vary with the orientation. Often the orientation of these length scales is related to the orientation of the boundaries. Such solution fields can be captured by the finite element method, using a mesh that is refined in the direction of the short length scales and coarse in the other directions. These meshes contain elements with high aspect ratios in a predefined pattern.The mesh generator presented here can render triangles with high aspect ratios through a paving algorithm. The paving algorithm that is employed applies both triangles and quadrilaterals, combining the advantages of both to render a qualitatively good, oriented triangular mesh, with a concentration of elements in the direction where the internal length scales of the solution field are the shortest.The mesh generator produces triangles with one (almost) orthogonal corner. When low aspect ratio triangles are generated, these are well suited for conversion to quadrilateral elements. Test results indicate that quadrilateral meshes converted from the mesh generator introduced here have a considerably better quality than those converted from several other triangular mesh generators.  相似文献   

17.
从数据模型的任意一点开始选择一个初始的四边形网格单元,采用动态边界边扩展的方法在三维空间直接进行四边形网格划分;在网格划分过程中实现了边界冲突检测、网格顶点优化处理、网格边界处理和网格综合优化.最后给出了网格生成实例.实验结果表明:该算法生成的网格质量较好,运行速度较快.  相似文献   

18.
In this paper a new indirect approach is presented for anisotropic quadrilateral mesh generation based on discrete surfaces. The ability to generate grids automatically had a pervasive influence on many application areas in particularly in the field of Computational Fluid Dynamics. In spite of considerable advances in automatic grid generation there is still potential for better performance and higher element quality. The aim is to generate meshes with less elements which fit some anisotropy criterion to satisfy numerical accuracy while reducing processing times remarkably. The generation of high quality volume meshes using an advancing front algorithm relies heavily on a well designed surface mesh. For this reason this paper presents a new technique for the generation of high quality surface meshes containing a significantly reduced number of elements. This is achieved by creating quadrilateral meshes that include anisotropic elements along a source of anisotropy.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号