In order to develop a simple method for predicting the twisting deformation of the longitudinal stiffeners by the line heating quantitatively, simple mechanical models are proposed. The proposed model is applied to understand the mechanism of forming in the compression, the in-plane bending and the twisting mode. Further, a simple equation to predict mechanism of shrinkage, bending and twisting process in the line heating of plate is investigated based on simple mechanical model and FEM analyses. As a result, it is found that the larger heating angle is preferable for obtaining the twisting deformation.

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To clarify the mechanism of the ductility-dip cracking formed under the weld bead, thermal-elastic-plastic FEM is performed in this study. The increment of plastic strain and staying time in DTR are closely examined as an index of the cracking. From the results of this study, it is found that these parameters become larger under the weld bead. Thus, the crack is likely to be formed. The same tendency is observed in the results of FEM using the temperature dependent interface element developed by the authors.

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First,the author designed an inside room for inside space of a ship and designed an outside room for outside space of a ship. Then, the insideroom is sitting chair private room. And the outside room is sitting parted floor common room. Further, partition of the parted floor is an half height partition. Next,the author adopted the inside rooms and the outside rooms for a domesteic service middle size passenger ship. And, the author adopted all outside rooms for a domesteic service small size passenger ships.

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In order to assemble parts in shipbuilding, welding is commonly used. However it is impossible to avoid the deformation which is caused by welding. To predict the deformation during the assembly process, a finite element method that can consider the gap and contact between parts before and after welding is proposed. This method can be used to investigate the restraint by tack welds. In this study, the proposed method is applied to the welding deformation when two simple plates are jointed. The usefulness and the validity of the proposed method are demonstrated through the optimization of the welding sequence to minimize the distortion

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Surface piercing propellers (hereinafter SPP) are well known to give higher efficiency for high-speed ships but they have not yet became the popular propulsive devices because of their complex phenomena and lacking design method. In this paper, with the aim of the widespread use of SPP installed high speed ship, following studies were made.1) measurements and analysis of three component forces (resistance, lift and moment) acting on a hull, varying ship trim and sinkage, 2) Navigating simulation of SPP installed high speed ships by computer and consideration of propulsive performance

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The authors have developed a New Stem named "SEA-Arrow" to improve the propulsive performance of medium-speed such as LPG carriers. Having no protrusion of bulb, "SEA-Arrow" can reduce the bow waves and greatly increase the propulsive performance. In LPG carrier designs, limitations are provided in such as ships length overall, cargo hold volume and ship's speed. By adopting "SEA-Arrow", the authors could reduce the wave resistance to a half and achieve a 6-10% reduction in required main engine horsepower. This paper descrives the features of "SEA-Arrow" and its performance based on the test results.

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[in Japanese]

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This paper describes the development of the system of MEC (Marine Environmental Committee) Model programs which can directly be executed from internet browser. The system is named as MEC-Online Computation and Visualization System. In this paper the system of MEC-Online Computation and Online Visualization is explained briefly. The function of the menu of each MEC-Model element is given in detail. Some example results of visualization is presented in the last section of this paper.

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[in Japanese]

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[in Japanese]

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Experimental studies on ship motions in beam seas are carried out to find that the accuracy of a prediction method based on linear strip theory becomes worse in heavy seas. It is experimentally comfirmed that this is because drift velocity of a ship increases in heavy seas. Rapid drift motion causes the increase of the roll damping and the decrease of wave exciting roll moment on the hull. A prediction method for viscous roll damping in which the effect of drift motion on it is taken into account is developed.

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The added resistance due to wave on full form ships is mainly generated by the diffraction of the incident waves at the blunt bow. In order to decrease the diffraction of wave at the blunt bow, "Ax-Bow" which has sharpened bow shape above the still waterline was developed. The first vessel with Ax-Bow was Cape-Size Bulk Carrier delivered in 2001. The monitoring systems were installed on both Ax-Bow vessel and the sister vessel with ordinary bow. The hull performance measurement in actual sea has been carried out to verify the effect of Ax-Bow.

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The author presents optimization of pod housing and strut geometry by using CFD simulation technique and investigation of unsteady hydrodynamic force acting on a propeller and pod at neutral and steering condition with an exact method that takes account of unsteady term in related equations and interaction between the propeller and the pod. Next, he conducted tank tests in order to verify the CFD simulation results and obtain fundamental knowledge.

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Safety and performance of a ship should be primarily evaluated in its life cycle. In order to cope with this subject from hydrodynamic performance design of a ship, the conventional hull design method is needed to be changed into a new one based on prediction and evaluation of the performance under operation condition in actual sea.Under the above mentioned background, The Shipbuilding Research Association of Japan has conducted the ship research panel 244.This paper describes the outline of development of propulsive performance analysis system, which is a part of the products of the panel. The emphasis is on the explanation about EUT(Enhance Unified Theory) as ship motion analysis.

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3 dimensional simulations of nonlinear fluid phenomena by the particle method are time consuming computation. It is impossible to compute over one million particles even if by the latest single processor system.We develop a parallel processing numerical code that is targeted on PC cluster. The performance is evaluated and verified with a practical computation of over one million particles.

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It is well known that linear theory such as Strip Method is widely used to predict seakeeping performance of a ship and it can be applicable for relatively high wave condition. However, under the extremity high wave conditions, linear theory cannot be applicable.
In this research, a calculation method named "Practical Large Amplitude Ship Motion Analysis (PLASMA)" is developed. The feature of PLASMA is practical calculation time in such high wave case.
In this paper, the outline of PLASMA is presented first, then calculation results by PLASMA are compaered both with those by linear theory and towing tank test to show availability of PLASMA.

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Safety evaluations of ship handling are in fact dependent on subjectivity due to the imperfect objective index used for evaluating the results of experiments using a ship-handling simulator. In the present paper, a safety evaluation index that objectively determines the quantitative risks of collision and stranding when the experiment is executed using a ship-handling simulator is proposed, by noting Unsafe Ship Handling Situations.

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[in Japanese]

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[in Japanese]

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Practical simple formulae for estimating ultimate strength of continuous stiffened plates under combined uniaxial thrust and lateral pressure have been derived. For a combination of uniaxial thrust parallel to stiffener and lateral pressure, the existing estimation method proposed by the authors, has been simplified into a set of closed-form equations for a practical use in design. For a combination of uniaxial thrust perpendicular to stiffener and lateral pressure, the effects of stiffeners on the ultimate strength have been clarified based on FEA results, and a set of closed-form formulae of ultimate strength with consideration of stiffener effects have been newly developed.

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Recently, Navier-Stokes solvers have been used as a design analysis tool of practical ships. However, there are few reports available for the validation of sensitivities to small differences among many similar hull forms. In the present paper, the free-surface viscous flow computations around 12 domestic tankers were conducted by a flow solver NEPTUNE, developed in our laboratory and compared with the measured data. A very good agreement between the computations and the measurements, i.e. within 1.2% for form factors and 2% for total resistances, were achieved. Thus, CFD codes were found to be highly efficient for the ship design.

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The difference of a ship maneuvering performance in the water between shallow and deep is owing to the difference of the maneuvering hydrodynamic forces acting on ship-hull in the water between shallow and deep. The authors have developed a component-type mathematical model which is useful to describe the ship hull hydrodynamic forces in maneuvering motions in deep water. This study is a research for the applicability of the model to the ship-hull hydrodynamic forces in shallow water. The results is the model can describe the hydrodynamic forces within the range of conventional drift angles in shallow water as well as in deep water.

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[in Japanese]

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Recently the Particle method is highly receiving attention because of its simple theory and broad range of solving problems. In naval and marine field the MPS method is used in some studies. In this study the authors think of pressure fluctuation under the rolling tank problem. First comparison between the experiment value and the solution by the MPS methos is carried out. Then the problems in the original MPS method are found. Next the authors consider improvement of the weighting function related to particle number density in the MPS method.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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A method is proposed for evaluating the effects of human activities in the coastal land area on the environments in the coastal sea area. Applying the cross impact matrices, multi-regression analysis, parameters for evaluating the environmental impacts to the environments of coastal sea area are estimated. Then, the SD-modelling technique is applied for evaluating the effects of human activities on environmental impact analysis.

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[in Japanese]

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