| Project/Area Number |
05402056
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
海洋工学
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| Research Institution | University of Tokyo, Institute of Industrial Science |
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Principal Investigator |
MAEDA Hisaaki University of Tokyo, Institute of Industrial Science, Professor, 生産技術研究所, 教授 (80013192)
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| Co-Investigator(Kenkyū-buntansha) |
FUJINO Masataka University of Tokyo, Faculty of Engineering, Professor, 工学系研究科, 教授 (10010787)
MIYAJIMA Syougo University of Tokyo, Institute of Industrial Science, Lecturer, 生産技術研究所, 講師 (40200175)
MASUDA Koichi Nihon University, College of Science and Engineering, Professor, 理工学部, 教授 (10120552)
TOI Yutaka University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (40133087)
KINOSHITA Takeshi University of Tokyo, Institute of Industrial Science, Associate Professor, 生産技術研究所, 助教授 (70107366)
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| Project Period (FY) |
1993 – 1995
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| Keywords | MULTI-DIRECTIONAL OCEAN WAVEW / NON-GAUSSIAN PROCESS / NON-LINEAR BEHAVIOR / OFFSHORE STRUCTURES / STATISTICAL ANALYSIS / PREDICTION OF EXTREMUM |
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| Research Abstract |
The prediction method of extremum for motion responses or waves loads in severe sea conditions have not been developed yet, since the responses are non-Gaussian. And there have been many marine facilities or bulk-carriers which suffered structural damages, sank and lost many lives. There have reported several examples which shows that the Rayleigh method was not hold for non-Gaussian cases. That is the reason why wer start to develop the practical prediction method of extremum for non-Gaussian process.
We first tried to predict extremum of low frequency motions of a catenary moored floating structures in multi-directional waves. If only external wave excitations are non-linear and the other terms, radiation hydrodynamic forces and damping term and restoring term are all linear, then the method developed by Naess or Kato-Kinoshita works well, however, if we introduce non-linear terms in the left hand side of the equation of motion, the analytical method based on Naess or Kato-Kinoshta does not function. Then we conclude that the only practical prediction method for full non-linear, non-Gaussian process is the time domain simulation method which is applicable to so called simulation based design.
We then developed the time domain simulation code for ship motions, waves loads and unsteady pressures on a ship hull with advanced speed and in multi-directional waves. Moreover we introduce non-linear terms to this time domain simulation.
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