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

本文将整体网格和局部网格相互叠加的叠加网格有限元法应用于二维弹性静力问题和板弯曲问题。与传统的缩放分析方法进行了比较，传统的缩放分析方法是将整体分析得到的位移或载荷边界条件用于局部分析。结果表明，虽然缩放分析的准确性很大程度上取决于全球网格的大小，覆盖网格分析通常给出了相当好的结果，即使在全球分析中使用粗网格。本文还提出了局部和整体分析的迭代方法，使通用有限元程序在网格重叠法中的应用成为可能，并证明了在松弛条件下的迭代收敛速度的提高。

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.