A COMPREHENSIVE STUDY ON THE CONSTRUCTION OF MEGA-FLOATING ARTIFICIAL ISLANDS

本研究旨在对漂浮人工岛等巨型浮式结构物的建造进行综合研究。该结构的大小可能是几千米，其中可能包括浮动机场。长尾研究了这样一种浮式结构的抗风设计。为了阐明这一点，他在平板箱形截面模型上进行了一些实验。结果表明，近距离风特性对风力有很大的影响。北原分析了地震作用下的流体-弹性地基-多孔地基系统。所采用的方法是边界元方法，三个域分别建模，并在其边界处组合。数值结果表明，基础下沉到地面对降低地应力是有效的。Funaki对悬链线系泊的大型海洋结构物进行了研究，考察了悬链线的重量和刚度的影响。根据ABAQUS的暂态分析结果，将悬链线的非线性效应线性化。上田教授研究了由矩形和半圆形组成的浮体结构，并用源分布法分析了水动力(绕射力和辐射力)。渡边教授和宇都宫博士研究了考虑结构弹性变形的大型浮式结构的波浪响应分析。采用有限元方法对流体域和结构域进行了数值模拟，并将直接频率法应用于波浪响应分析。编制了HOBEM(高阶边界元)程序，并对超大型浮体进行了分析。

This study aims at a comprehensive study on the construction of Mega-floating structure such as floating artificial islands. The size of the structure may be several kilo-meters, which may include floating airport.Prof. Nagao studied on the wind resistant design of such a floating structure. In order to clarify it, he performed some experiments on the flat box-sectional models. It has been obtained that the wind force will be significantly affected by the close wind characteristics.Prof. Kitahara analyzed the fluid-elastic foundation-porous ground system subjected to earthquake excitations. The method employed is the Boundary Element Method, and the three domains are separately modeled, and are combined at their boundaries. The numerical results have shown that the submergence of the foundation to the ground will be effective in terms of the reduction of ground stresses.Prof. Funaki studied on large offshore structures moored by catenary lines, and the effect of the weight and stiffness of the catenary lines were examined. The nonlinear effect of the catenary lines are linearized based on the results of transient analysis by ABAQUS.Prof.Ueda studied the floating structure consisting of rectangular and half-circular shapes, and the hydrodynamic forces (diffraction and radiation forces) were analyzed by the source distribution method. The floating bridges were also studied, and the effect of elasticity of the superstructure were examined.Prof.Watanabe and Dr.Utsunomiya studied on the wave response analysis of large floating structure considering elastic deformation of the structure. The fluid and structural domains were both modeled by Finite Element Method, and the direct frequency method has been applied to wave response analysis. The HOBEM (Higher Order Boundary Element Method) program has also been developed, and the VLFS (very Large Floating Structure) has also been analyzed.