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适用于邻近几何特征的非结构面网格生成方法

Adaptive Unstructured Surface Mesh Generation Method for Arbitrary Geometry with Proximity Features

  • 摘要: 自主仿真分析是亟待解决的难题, 其中网格划分用时占据了前处理过程的73%, 网格划分仍是整个数值模拟过程中的主要技术瓶颈. 为此, 提出一种适用于邻近几何特征的非结构面网格生成方法. 该方法根据网格尺寸、边曲率、面曲率等几何参数进行网格自适应细分, 采用穿插法和最近距离法等对网格节点进行实体边界拟合; 为了有效地构建核心锯齿状网格, 提出一种快速求解网格拓扑元素与实体模型边界相交的算法; 对于具有邻近几何特征的复杂实体模型(如疲劳裂纹扩展分析模型), 提出基于邻近几何特征通用模板的高质量实体边界拟合方法, 解决了传统“由外向内”栅格法的实体边界拟合难题. 工程算例结果表明, 所提方法可将具有邻近特征的实体模型进行以四边形为主的网格划分, 生成网格有单元质量高、区域关键特征表达准确等特点, 并已成功地应用于具有国产自主研发仿真内核的5aCAE软件中.

     

    Abstract: Automatic simulation is an urgent challenge to be solved. For complex geometries, 73 percent of the total available CPU time is spent on mesh generation, which is still a bottleneck in the preprocessing module. Therefore, an unstructured mesh generation algorithm for arbitrary geometry with proximity features is presented. The refinement field is constructed according to mesh size, boundary curvature, surface curvatures and other geometry features. The geometry fitting techniques and the nearest distance methods are adopted to approximate the solid boundary of the mesh nodes. In order to effectively construct the core jagged mesh, a fast intersection algorithm is established to solve the intersection of mesh topology elements with the solid model boundary, which improves the efficiency of intersection calculation. For complex entities with proximity features, such as the models used in analysis of fatigue crack growth, a new type of proximity feature template is proposed, which successfully solves the problem of entity boundary fitting of the traditional out-side-in mesh method. Numerical examples show that the proposed method can perform quadrilateral-based meshing for solid models with proximity features, and the generated mesh has the characteristics of high cell quality and accurate expression of key features in the region. And the research findings have been seamlessly integrated into the domestically-produced and highly-autonomous 5aCAE software.

     

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