A Study on Accurate Zooming Analysis for Ship Structure

有限元法是船舶结构等大型结构应力分析的常用方法。然而，大型结构的有限元分析需要大量的计算工作量。因此，通常使用缩放分析。有两种类型的放大分析。一种是位移法，另一种是应力法。由于位移法易于应用，因此该方法被普遍使用，然而，应力法具有给出更精确解的潜力。本研究将应力法应用于平面问题和板弯曲问题，研究了超收敛的分片恢复法。据报道，SPR方法的精度取决于采样点的位置和近似函数。指出在2 × 2高斯点上采样应力解提高了恢复解的精度，并将应力类型细化分析应用于船体结构分析。考虑了散货船模型，该模型最初有40，000多个单元。在此基础上，采用了变尺度分析方法，得到了比位移型变尺度分析高两倍的精度解。

Finite element method is commonly used for stress analysis for large structures such as ship structure. However, finite element analysis for large scale structure requires a large computational efforts. Hence, a zooming analysis is generally used. There two type zooming analysis. One is Displacement method and the other is stress method. Since Displacement method is easy to be applied, the method is commonly used, however ; stress method has a potential to give more accurate solutions. In this study, the stress method is under consideration to be improved its accuracy.Superconvergent patch recovery (SPR) method is studied in plane problems and plate bending problems. It is reported that the accuracy of SPR method is dependent on the location of the sampling points and the approximate function. It is also pointed out that sampling stress solutions on the 2X2 gauss points improve the accuracy of the recovered solution in this study.The stress type zooming analysis is applied in ship structure analysis. The bulk carrier model, which has more than 40,000 elements originally, is considered. The zooming analysis is applied and about two times accurate solution is obtained in this analysis compared to the displacement type zooming analysis.