• Journal of Ocean Engineering and Technology
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• v.12 no.3 s.29
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• pp.103-111
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• 1998

This paper describes the initial hull form design process which generate a hull form using a neurofuzzy modeling. Neurofuzzy system is to combine the merits of fuzzy inference system and neural networks. Therefore it has structured knowledge representations as well as adaptive capacities. Initial hull form design stage is the process which generate an adoptable hull form from the limited design information and multi-decidions condidering correlations with design factors. It can be assidted efficiently by neurofuzzy system. This paper suggests two methods of an initial hull form generation using the neurofuzzy modeling and B-spline theory. and examines the usefulness of suggested method through its application examples.

• Special Issue of the Society of Naval Architects of Korea
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• 2017.10a
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• pp.59-62
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• 2017

Recently oil price has got lower, but energy efficiency has been considered as an important factor to minimize ship operational costs and reduce greenhouse gas emissions. For the reason, it is necessary that energy efficiency improvement for hull form design and operational performance reflect an understanding of the vessel's operational profile. Throughout the life of the vessel, this can lead to important economies of fuel, even if, in some cases, a small penalty can be taken for design condition. In the present paper, hull form was developed for 5,000TEU class container carrier at given operation profile. As a CFD result at several design point, optimized hull form has improved resistance performance in comparison with the basis hull form. To reducing the viscosity and the wave resistance at multi draft and multi speed, the hull form was investigated for Cp-curve, frame and local shape. Numerical study has been performed using WAVIS & Star-CCM+ and verified by model test in the towing tank.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1997.10a
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• pp.237-240
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• 1997

This paper is to arrange systematically the geometrical & physical data for real ships and to develop the graphic user interface program for initial hull design using NFHFD, which save the distributed information about hull form database and can output multi-variables.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.32-47
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• 1996

Systematic theoretical arm experimental studies have been performed to establish the methods of the hull form design, the optimum dimension selection and the resistance estimation for the displacement type super high-speed ships. In this study, theoretical hull form design method of the displacement type super high-speed ships has been developed first by the minimum resistance theory and the sectionally-varying hull form equation. Utilizing the established hull form design method, sixty(60) series hull forms have been prepared according to the systematic variations of the important design variables, and model tests were conducted for the sixty(60) series ship models. Finally, regression analyses have been performed for the results of model tests. It is considered that this is the first systematic and multi-purpose study in the world for the super high-speed ships. The study has been completed very successfully. The prepared computer program is now being actively utilized as an efficient tool for the design of the displacement type super high-speed ships.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.2
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• pp.98-108
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• 2006

The vessels, already built and is operating in Korea, have the hull form of catamaran, with LOA(Length Over All) 15 m, LBP(Length Between Perpendiculars) 12 m, GT(Gross Tonnage) 9.77ton, Light Load Displacement 15.1ton. Korean Society of Ship Inspection & Technology, Chungnam National University, Inha University, Seoul National University and Advance Marine Tech co. ltd developed by cooperation it for fishing vessels. And it used FRP(Fiber Reinforced Plastics) for hull material and main engine of diesel $360ps{\times}2800rpm{\times}2sets$ with a water jet system. Based on these results, this paper describe small leisure fishing vessels with multi-hull, in relation to the project of CTYS(Regional Reserch Center for Transportation System of Yellow Sea Inha University) that aimed to development of trimaran hull form(LOA=17m, LBP=14m(Side Hull=6m), GT=9.77ton, Light Weight=11.2 ton).

• Journal of the Society of Naval Architects of Korea
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• v.41 no.1
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• pp.15-22
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• 2004

Twin-skeg type stern shapes are recently adopted for very large commercial ships. However it is difficult to apply a CFD system to a hull form having twin-skeg, since grid topology around a twin-skeg type stern is more complicated than that of a conventional single-screw ship, or of an open-shaft type twin-screw ship with center-skeg. In the present study a surface mesh generator and a multi-block field grid generation program have been developed for twin-skeg type stern. Furthermore, multi-block flow solvers are utilized for potential and viscous flow analysis around a twin-skeg type stern The present computational system is applied to a 15,000TEU container ship with twin-skeg to prove the applicability. Wave profiles and wake distribution are calculated using the developed flow analysis tools and the results are compared with towing tank measurements.

• Korean Journal of Computational Design and Engineering
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• v.17 no.3
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• pp.188-197
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• 2012

Recently, aluminum ships are constructed more than ever because of the environmental pollution generated by FRP (Fiber Reinforced Plastic) ships. In particular, FRP ships have been replaced by the Aluminum ships. The forming process of the curved aluminum plate has been performed only by labor works without systematic technique. Therefore, it is difficult to construct the aluminum ship that the design satisfies both required propulsion performance and hull design. Present study introduces a MPSF (Multi Point Stretching Forming) that is a flexible manufacturing technique to form large sheet panels of doubly curvature. The hull pieces are stretch-formed over the MPSD (multi-point stretching die) generated by the punch element matrix. In this study, MPSF is applied to deform the doubly curved surfaces of aluminum ship. The forming system including FEA (finite element analysis) of the processes for stretching the plate were carried out by static implicit analysis is suggested. Residual deformation of the surface is modeled by an elasto-plastic contact phenomena while the forming process is simulated by FEA. Finally, the proposed system is also validated, comparing the deformed shape by MPSF with that of object surfaces.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.53-60
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• 2009

Recently, since there are several problems in space, the infra-structure and the facilities in the contiguity of the existing harbors due to the trend of enlarging the container capacity of the large container vessel, a special floating platform named as the Mobile Harbor has been proposed conceptually as an effective solution of those problems. Two kinds of hull shapes, a conventional mono-hull type and a catamaran type, are proposed as midway feeders to transfer containers to the harbor on land from a large container ship on near shore. In this study, the motion response and mooring analysis are carried out for comparing the global performance of two types of Mobile Harbor. Robot arm mooring facility specially is devised and newly tried to use for the safe fixation of a large container ship and the Mobile Harbor on near shore. It would be expected for this comparison study to give a guideline to design the efficient hull form for a midway loader.

• Journal of Ship and Ocean Technology
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• v.10 no.4
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• pp.1-11
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• 2006

The finite volume based multi-block RANS code, WAVIS developed at MOERI is applied to the numerical self-propulsion test. WAVIS uses the cell-centered finite volume method for discretization of the governing equations. The realizable $k-{\epsilon}$ turbulence model with a wall function is employed for the turbulence closure. The free surface is captured with the two-phase level set method and body forces are used to model the effects of a propeller without resolving the detail blade flow. The propeller forces are obtained using an unsteady lifting surface method based on potential flow theory. The numerical procedure followed the self-propulsion model experiment based on the 1978 ITTC performance prediction method. The self-propulsion point is obtained iteratively through balancing the propeller thrust, the ship hull resistance and towing force that is correction for Reynolds number difference between the model and full scale. The unsteady lifting surface code is also iterated until the propeller induced velocity is converged in order to obtain the propeller force. The self-propulsion characteristics such as thrust deduction, wake fraction, propeller efficiency, and hull efficiency are compared with the experimental data of the practical container ship. The present paper shows that hybrid RANS and potential flow based numerical method is promising to predict the self-propulsion parameters of practical ships as a useful tool for the hull form and propeller design.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.4
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• pp.211-226
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• 2015

Membrane type Mark III cargo containment system (CCS) is considered in this study to investigate its strength capability under applied loads due to liquefied natural gas (LNG) cargo. A rectangular plated structure supported by inner hull structure is exemplified from Mark III CCS according to classification society's guidance and it is assumed as multi-layered structure by stacking plywood, triplex, reinforced polyurethane (PU) foam and series of mastic upon inner hull structure. Commercially available general purpose finite element analysis package is used to have reliable FE models of Mark III CCS plate. The FE models and anisotropic failure criteria such as maximum stress, Hoffman, Hill, Tsai-Wu and Hashin taking into account the direction dependent material properties of Mark III CCS plate components and their material properties considering a wide variation of temperature due to the nature of LNG together form the strength analysis procedure of Mark III CCS plate. Strength capability of Mark III CCS plate is understood by its initial failure and post-initial failure states. Results are represented in terms of failure loads and locations when initial failure and post-initial failures are occurred respectively. From the results the basic design information of Mark III CCS plate is given.