EVALUATION OF SAFETY OF FLOATING ARTIFICIAL ISLANDS

海洋工程师对长达数千米的浮动结构的概念感兴趣。这类结构旨在用于，例如，漂浮机场的异常大小可能需要新技术，特别是为了在很长一段时间内，比如100年，准确地评估它们的安全性。对于这种类型的结构，对其安全性的预测必须非常可靠。该项目的目标是建立一种新的方法来评估大型浮式结构物的安全性，这些浮式结构物的尺寸非常大，预计的年龄也很大。为此，我们进行了研究。(1)与地形尺度相当的浮式建筑物对风浪的响应及其合理的预报方法。(2)提高了极长周期(100年)海浪预报的可靠性，特别是在预计部署浮岛的近岸地点。我们的研究结果如下。(A)建立了由多个垂直圆柱体和截断圆柱体浮子支撑的浮动平台上波浪力的解析计算方法，并进行了数值实现。在该方法中，用数学上正确的方法考虑了海岸地形的影响。(2)研究了大型浮式结构物与海洋相互作用时的水弹性行为，提出了正确的预测方法。(3)根据九州大学应用力学研究所海塔的波浪观测资料和一个新的数学波浪预报模型，提出了近岸区和很长时间内波浪预报的新方法。

Ocean engineers are interested in concept of floating structures as large as several thousand meters long. This type of structures are intended to be used as, for example, floating airports unusual size of them may require new technology especially for accurate evaluation of their safety for very long period, say 100 years. Prediction of their safety must be extremely reliable with this type of structures. Objective of this project is to establish a new methodology for evaluating the safety of large floating structures of unusually large size and unusually large age expected. For this we have studied. (1) Response of floating structures, whose scale is comparable to the topographical scale, to stormy waves and its rational predicition method. (2) Improvement of reliability of wave forecast for very long period (100years) at the sites in particular, close to shore where the floating islands are expected to be deployed. Our results are as follows. (a) Analytical method to predict wave forces on a floating platform supported by numerous floats of vertical and truncated circular cylinder was developed and numerically implemented. In this method the topographical effect at shore region is accounted for mathematically correct way. (b) Hydroelastic behavior of large floating structure interacting sea was studied and its correct prediction method was proposed. (c) We proposed a new methodology of wave forecast at shore region and for very long years based on the wave observation data by the ocean tower of Research Institute of Applied Mechanics, Kyushu University and a new mathematical wave forecast model.