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This paper presents an outline of a comprehensive program system developed by the authors, which includes many functions for response analysis of a wide variety of offshore structures. Typical calculated results by this system are also... more
This paper presents an outline of a comprehensive program system developed by the authors, which includes many functions for response analysis of a wide variety of offshore structures. Typical calculated results by this system are also presented being compared with field measurements and model test data as well as calculations by the other analysis programs. Through the comparative calculations the validity and flexible applicability of the system have been confirmed and the results presented here may be valuable and useful for the designers and researchers of offshore structures.
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This paper outlines a total analysis system for ship hull structures, which integrates a wide variety of analysis functions to realise practical applications of rational methods for assessing ship structural strength. It is based on... more
This paper outlines a total analysis system for ship hull structures, which integrates a wide variety of analysis functions to realise practical applications of rational methods for assessing ship structural strength. It is based on direct calculation of wave-induced loads as well as three-...
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This paper presents the results of comparative calculations on structural responses of a typical semisubmersible and the discussion on design waves for brace stresses. A typical semisubmersible of two-lowerhull type is adopted as a... more
This paper presents the results of comparative calculations on structural responses of a typical semisubmersible and the discussion on design waves for brace stresses. A typical semisubmersible of two-lowerhull type is adopted as a full-scale model for the comparative calculations on three-dimensional motion and structural responses. Based on the comparative calculations by eight different computer programs, standard response functions are proposed as to axial and bending stresses of major braces. Characteristic wave loading patterns, which correspond to design waves, are proposed based on the standard stress response functions. Also simplified equations of wave forces on semisubmersibles, which are useful to consider design waves, are derived based on the assumptions of taking account of only hydrodynamic inertial forces. Based on these results, maximum brace stresses during a 100-yr return period are estimated using design wave method, and are compared with statistically estimated values by short-term and long-term predictions. As a result, it is found that design wave method has a tentative ground for practical design of semisubmersibles.
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This paper describes experimental studies on the motion, mooring tension and structural responses of a typical semisubmersible in regular waves. A 1/50-scale structural dynamic model of two-pontoon type was made of acryl and the tank... more
This paper describes experimental studies on the motion, mooring tension and structural responses of a typical semisubmersible in regular waves. A 1/50-scale structural dynamic model of two-pontoon type was made of acryl and the tank tests were carefully carried out. The measured platforms motions of the model were compared with calculations and close agreement was obtained. As to the structural responses the measured values of the test model agree approximately with the calculated results of a full-scale model. The close experimental results of structural responses presented here are expected to be valuable for the design of similar types of semisubmersibles.
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The dynamic response characteristics of the taut-moored platform or the so-called Tension Leg Platform in regular waves are studied both by several series of tank tests and by some simplified methods of linear and nonlinear analyses. By... more
The dynamic response characteristics of the taut-moored platform or the so-called Tension Leg Platform in regular waves are studied both by several series of tank tests and by some simplified methods of linear and nonlinear analyses. By comparison of the results it is shown that the analytical methods are valid and practical. In this paper the nonlinear responses observed in the model tests, as well as the characteristics of the linear frequency responses, are discussed in detail and clarified. In addition, statistical analysis is carried out on a full-scale TLP model in a real sea state.
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The paper discusses wave-induced structural responses of semisubmersibles based on comparative calculations of brace stress response functions for a typical semisubmersible, simplified estimation of wave loads and statistic and... more
The paper discusses wave-induced structural responses of semisubmersibles based on comparative calculations of brace stress response functions for a typical semisubmersible, simplified estimation of wave loads and statistic and deterministic predictions of maximum brace stresses. A typical semisubmersible of two-lowerhull type is adopted as a full-scale model for the comparative calculations on three-dimensional motion and structural responses. Based on the comparative calculations by eight different computer programs, standard response functions are proposed as to axial and bending stresses of major braces. Characteristic wave loading patterns, which correspond to design waves are proposed based on the standard stress response functions. Also simplified equations of wave forces on semisubmersibles, which are useful to consider design waves are derived based on the assumptions of taking account of only hydrodynamic inertial forces. Based on these results, maximum brace stresses duri...
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Some of the results of a comprehensive research project on ship structural safety carried out by Nippon Kaiji Kyokai (also known as ClassNK) in co-operation with several Japanese universities and ship research organisations in order to... more
Some of the results of a comprehensive research project on ship structural safety carried out by Nippon Kaiji Kyokai (also known as ClassNK) in co-operation with several Japanese universities and ship research organisations in order to propose a rational, transparent and yet practical assessment method of ship structural strength to ship designers, ship operators and concerned parties in the maritime community are presented here.The significant findings presented in this paper include four different short-term sea states, practical formulae for design loads, a realistic fatigue assessment method considering the effect of mean stress, and a probabilistic simulation model of the corrosion process of ship structures. The details of a new direct strength analysis system incorporating the above findings are also described.
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Research Interests:
This paper presents an outline of a comprehensive program system developed by the authors, which includes many functions for response analysis of a wide variety of offshore structures. Typical calculated results by this system are also... more
This paper presents an outline of a comprehensive program system developed by the authors, which includes many functions for response analysis of a wide variety of offshore structures. Typical calculated results by this system are also presented being compared with field measurements and model test data as well as calculations by the other analysis programs. Through the comparative calculations the validity and flexible applicability of the system have been confirmed and the results presented here may be valuable and useful for the designers and researchers of offshore structures.
Research Interests:
Research Interests:
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Research Interests: Medicine()
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Research Interests: Geology()
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... analysis are investigated with respect to modeling extent, support conditions, and compensation of unbalanced forces based on a series of comparative structural analyses using hold structure models and entire ship models of a VLCC and... more
... analysis are investigated with respect to modeling extent, support conditions, and compensation of unbalanced forces based on a series of comparative structural analyses using hold structure models and entire ship models of a VLCC and an Aframax tanker with double hull ...
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This paper describes experimental studies on the motion, mooring tension and structural responses of a typical semisubmersible in regular waves. A 1/50-scale structural dynamic model of two-pontoon type was made of acryl and the tank... more
This paper describes experimental studies on the motion, mooring tension and structural responses of a typical semisubmersible in regular waves. A 1/50-scale structural dynamic model of two-pontoon type was made of acryl and the tank tests were carefully carried out. The measured platforms motions of the model were compared with calculations and close agreement was obtained. As to the structural responses the measured values of the test model agree approximately with the calculated results of a full-scale model. The close experimental results of structural responses presented here are expected to be valuable for the design of similar types of semisubmersibles.
Research Interests:
The dynamic response characteristics of the taut-moored platform or the so-called Tension Leg Platform in regular waves are studied both by several series of tank tests and by some simplified methods of linear and nonlinear analyses. By... more
The dynamic response characteristics of the taut-moored platform or the so-called Tension Leg Platform in regular waves are studied both by several series of tank tests and by some simplified methods of linear and nonlinear analyses. By comparison of the results it is shown that the analytical methods are valid and practical. In this paper the nonlinear responses observed in the model tests, as well as the characteristics of the linear frequency responses, are discussed in detail and clarified. In addition, statistical analysis is carried out on a full-scale TLP model in a real sea state.
Research Interests:
This paper outlines a total analysis system for ship hull structures, which integrates a wide variety of analysis functions to realise practical applications of rational methods for assessing ship structural strength. It is based on... more
This paper outlines a total analysis system for ship hull structures, which integrates a wide variety of analysis functions to realise practical applications of rational methods for assessing ship structural strength. It is based on direct calculation of wave-induced loads as well as three-...