Study on high-precise zooming analysis of ship structures using multi-grid method

将全局网格和局部网格相互覆盖的覆盖网格有限元法应用于二维弹性静力问题和板弯曲问题。结果与传统的变焦分析进行了比较，变焦分析将全局分析得到的位移或荷载边界条件赋给局部分析。结果表明，虽然缩放分析的精度很大程度上取决于全局网格的大小，但即使采用粗网格进行全局分析，覆盖网格分析通常也能得到很好的结果。同时提出了局部和全局迭代重复分析的方法，使通用有限元程序可以应用于覆盖网格法中，并证明了在松弛条件下使用该方法可使收敛速度加快。

The overlaying mesh finite element method, which uses global and local mesh that overlies each other, is applied for 2 dimensional elastostatic problem and plate bending problem. The results are compared with the traditional zooming analysis, in which displacement or load boundary conditions obtained by global analysis are given to local analysis. It was shown that while the accuracy of zooming analysis greatly depends on the size of the global mesh, the overlying mesh analysis generally gives quite good results even when coarse mesh is used in global analysis. Also the method that repeat local and global analysis iteratively is proposed, which makes it possible to use general purpose FEM code in overlaying mesh method, and it was shown that using under relaxation the convergence speed increase.