A Study on Optimization of Huge Ocean Structure through the Choice of Hull Forms and Mooring in Waves

为研究“巨型海洋结构物在波浪中的选型与系泊优化”，本课题开展了以下研究工作：1)优化方法综述2)海洋结构物二维最小波浪激振力的优化方法3)二下壳式海洋结构物最小波浪激振力的优化方法4)柱支承式海洋结构物最小波浪激振力的优化方法5)下部船体海洋结构物最小波浪力的优化方法利用本文提出的优化方法，得到了具有最小波浪激振力的最优外形。2)同样的讨论也得到了具有最小传输系数的最优外形。3)对于整体巨型海洋结构，将波浪激振力作为衡量优劣的指标进行了简化，以便于实际计算。因此，在本研究中，波浪激振力的计算公式不包括所谓的波浪绕射力。4)然而，利用巨型海洋结构单元进行的模型试验表明，最小波浪激振力的波浪周期与试验结果不同。为了改善这一点，还将进行进一步的研究。

In order to study on "Optimization of Huge Ocean Structuer through the Choice of Hull Forms and Mooring in Waves", the following research items have been done during the term of this project :1) Survey of the optimization method2) Optimization method for the minimum wave exciting forces on a two-dimensional shape of a ocean structure3) Optimization method for the minimum wave exciting forces on a 2-lower hull type ocean structure4) Optimization method for the minimum wave exciting forces on a column supported type ocean structure5) Optimization method for the minimum wave forces on a lower hull type ocean structureFrom this study the following results have been obtained :1) For the elements of huge ocean structure, an optimal shape with minimum wave exciting forces is obtained by use of a present optimization method.2) Same discussion is applied to obtain an optimal shape with minimum transmission coefficients.3) For a overall huge ocean structure is concerned, the wave exciting forces as a measure of merit are to be simplified for the practical calculations. Therefore, in this study, the wave exciting forces are formulated excluding the so called diffraction force due to waves.4) However, the model experiments by use of elements of huge ocean structure showed that the wave period for minimum wave exciting force was different between calculations and experiments. In order to improve this, further study will be carried out.