中文摘要：

有限元数值分析的精度和效率与网格单元的划分质量以及疏密程度密切相关，针对三维六面体网格单元之间疏密过渡必须平缓和协调的要求，提出了一套基于8分法的六面体网格加密模板，并给出了相应的数据结构和模板应用方式．为使所有加密单元都有相对应的加密模板，建立了加密信息场调整规则；对需要进行加密的区域首先补充加密单元，按照节点加密属性调整加密信息场，然后根据单元加密属性对加密单元进行分类，按照全加密单元、面加密单元、边加密单元以及过渡加密单元的顺序依次采用相应的模板进行加密，从而实现三维六面体网格的局部协调加密．实例结果表明，采用该套加密模板的六面体网格局部加密算法能够保障密集网格向稀疏网格的平缓和协调过渡，所生成的网格可满足有限元数值计算的要求．

英文摘要：

The accuracy and efficiency of finite element numerical analysis have close relationship with the mesh quality and density distribution. In order to ensure the hexahedral mesh transition gradually and conformably, a set of 8-refinement based density control templates is proposed newly. The corresponding date structure and template application techniques are also given. Adjustment rules are built for conversion of every element in the refinement field to a corresponding 8-refinement based density control template. For the regions to be refined, the refinement elements are firstly supplemented. Secondly, the refinement fields are adjusted according to the node refinement attribute. Thirdly, the elements to be refined are classified into all refinement element, face refinement element, edge refinement element and transition refinement element according to the element refinement attribute and then refined with the corresponding template respectively. Thus the local refinement of all-hexahedral meshes can be realized. The examples show that the local refinement algorithm can guarantee the gradual and conformal transition from dense meshes to sparse meshes by using the 8- refinement based density control templates. The generated mesh can satisfy the requirement of finite element numerical analysis.