• Title/Summary/Keyword: Hull-form design

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Multi Point Press Stretch Forming System Applied to Curved Hull Plate of Aluminum Ship (알루미늄 선박의 외판 가공을 위한 인장성형 시스템 연구)

  • Bae, Chul-Nam;Hwang, Se-Yun;Lee, Jang-Hyun;Jeong, Uh-Cheul;Kim, Kwang-Ho
    • 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 In particular, FRP ships have been replaced by the Aluminum ships.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.

Hull Form and Layouts of 740-ton Replacement Vessel for R/V Eardo of KIOST: Ship Design and SMRs (740톤급 종합해양연구선 이어도호 대체선 선형 및 설계 특성)

  • Park, Cheong Kee;Park, Dong-Won;Lee, Gun Chang;Kim, Young Jun;Min, Young Ki
    • Ocean and Polar Research
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    • v.42 no.2
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    • pp.171-178
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    • 2020
  • R/V EARDO, commissioned in 1992, has successfully carried out ocean research campaigns in Korean jurisdictional and adjacent waters, including continental margins and coastal zones within the Korean Exclusive Economic Zone (EEZ), for 29 years. However, it will soon be reaching the end of its useful service life. A replacement for R/V EARDO is urgently needed to ensure the safety of vessel itself and its crews, and efficient ship operation and maintenance, as well as to meet modern scientific mission requirements (SMRs). Basic specifications for a replacement ship have been devised and reviewed over the past nine months. A test of the proposed hull form was also performed. The total tonnage of the proposed vessel is approximately 740 tons, and the overall length and width are 62.0 and 11.6 m, respectively. The new ship will thus be 73% larger than the current R/V EARDO; in particular, the research workspace will be 4.4 times larger. The major design priorities are the propulsion system, efficiency of radiated noise and vibration control, and the dynamic positioning system. An environmentally friendly emission system, meeting International Maritime Organization (IMO) Tier III regulations, will be installed in the third exhaust pipe. Various wet and dry lab spaces as well as 32 different scientific instruments have also been considered in the ship design.

Hull Form Optimization using Parametric Modification Functions and Global Optimization (전역 최적화기법과 파라메트릭 변환함수를 이용한 선형 최적화)

  • Kim, Hee-Jung;Chun, Ho-Hwan;An, Nam-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.45 no.6
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    • pp.590-600
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    • 2008
  • This paper concerns the development of a designer friendly hull form parameterization and its coupling with advanced global optimization algorithms. As optimization algorithms, we choose the Partial Swarm Optimization(PSO) recently introduced to solve global optimization problems. Most general-purpose optimization softwares used in industrial applications use gradient-based algorithms, mainly due to their convergence properties and computational efficiency when a relatively few number of variables are considered. However, local optimizers have difficulties with local minima and non-connected feasible regions. Because of the increase of computer power and of the development of efficient Global Optimization (GO) methods, in recent years nongradient-based algorithms have attracted much attention. Furthermore, GO methods provide several advantages over local approaches. In the paper, the derivative-based SQP and the GO approach PSO are compared with their relative performances in solving some typical ship design optimization problem focusing on their effectiveness and efficiency.

Motion Control of a SWATH Ship in Waves (파랑중 최소수선면적 쌍동선(SWATH)의 운동제어)

  • Lee, Pan-Muk;Lee, Sang-Mu;Hong, Sa-Yeong;Hong, Do-Cheon
    • 한국기계연구소 소보
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    • s.17
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    • pp.157-165
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    • 1987
  • The SWATH concept hull form which is capable of high speed navigation with small oscillatory motions in waves, was developed from the catamaran type hull forms. This paper describes how the motion of a SWATH ship in irregular waves can be reduced by regulating the stabilizing fins. The optimal regulator and LQG (Linear Quadratic Gaussian) controller for vertical plane motion have been applied for both platforming mode and contouring mode controls. The calculations of hydrodynamic coefficients and external forces are possible for defining the system equation for the design purpose of motion control. Performances of the controlled system are compared with those of original system.

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A Study on the Hull Design & Hull-Form Test for Catamaran Sailing Yacht (카타마란 세일링요트의 선형설계 및 선형시험 연구)

  • Jin, Song-Han;Sim, Sang-Mog;Go, Jung-Nam
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.2
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    • pp.55-60
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    • 2006
  • 최근 우리나라는 일반인들의 레저에 대한 관심이 고조되고 있고, 선진국형 해양레저에 대한 관심과 수요가 크게 증가하고 있는 실정이다. 특히, 해양레저의 꽃이라 할 수 있는 세일링요트 및 관련 장비 경우에는 대부분 전량 수입에 의존하고 있어 국산화 개발이 시급히 요구되고 있는 실정이다. 따라서 세일링요트 중에서 넓은 갑판면적 및 안정된 운항성능을 가지는 카타마란형 세일링요트의 선형설계와 형상에 따른 성능/특성 검증 위한 선형시험 등을 수행하여 국내에 적합한 카타마란형 세일링요트의 기초 자료를 정립하여 중소형조선소의 레저선박 관련 기술경쟁력 확보와 해양레저 활성화에 도움을 주고자 한다.

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Representation of Ship Hull Surface Using B-Spline (B-Spline을 이용한 선체표면의 표현에 관한 연구)

  • B.H.,Yoon;S.W.,Sur;W.D.,Kim;K.W.,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.22 no.3
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    • pp.19-26
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    • 1985
  • This paper deals with the representation and fairing of ship hull using a B-spline surface which is known as a 3-D model in computer aided free-form design. The first part of this paper is devoted to the fundamental concepts of B-spline theory and its geometrical characteristics. In its second part are described the facillities for efficient application, fast rendering of B-spline surface, and intersection of B-spline surfaces. The examples are presented with actual application to a real ship in the last part. And also a new concept of evaluating the surface fairness by the Gaussian curvature isolines is briefly discussed and its examples are presented.

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NUMERICAL DIFFUSION DECREASE OF FREE-SURFACE FLOW ANALYSIS USING SOURCE TERM IN VOLUME FRACTION TRANSPORT EQUATION (볼륨비 이송방정식의 소스항을 이용한 자유수면 유동 해석의 해 확산 감소)

  • Park, Sunho;Rhee, Shin Hyung
    • Journal of computational fluids engineering
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    • v.19 no.1
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    • pp.15-20
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    • 2014
  • Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code, termed SNUFOAM, which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley model ship. In results, the band width of the volume fraction contours between 0.1 to 0.9 at the hull surface was narrowed by considering the anti-diffusion term.

A Study on the Possibility of Hull Form Design using Numerical Towing Tank (SHIPFLOW)

  • Lee, Kwi-Joo;Joa, Soon-Won;Sun, Jae-Ouk
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.251-253
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    • 2003
  • This paper discusses some practical problems of the determination of ship wave resistance from flow calculation and the model test. there are so many kind of CFD program as FLUENT, WAVIS, SHIPFLOW, COMET etc. for finding optimized hull. we should know how much percent we trust the program. so if we gather computed values of the wave resistance we'll able to get more accurated values of presumptive.

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Motion Response and Mooring Analysis of Mobile Harbors Moored in Side-by-side (병렬 계류된 모바일하버의 운동응답 및 계류 해석)

  • Kim, Young-Bok
    • 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.

Numerical Investigation of Anti-Diffusion Source Term for Free-Surface Wave Flow

  • Park, Sunho;Lee, Heebum;Rhee, Shin Hyung
    • Journal of Advanced Research in Ocean Engineering
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    • v.2 no.2
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    • pp.48-60
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    • 2016
  • Accurate simulation of free-surface wave flows around a ship is very important for better hull-form design. In this paper, a computational fluid dynamics (CFD) code which is based on the open source libraries, OpenFOAM, was developed to predict the wave patterns around a ship. Additional anti-diffusion source term for minimizing a numerical diffusion, which was caused by convection differencing scheme, was considered in the volume-fraction transport equation. The influence of the anti-diffusion source term was tested by applying it to free-surface wave flow around the Wigley and KCS model ships. In results, the wave patterns and hull wave profiles of the Wigley and KCS model ships for various anti-diffusion coefficients showed quite close patterns. While, the band width of the water volume-fraction values between 0.1 to 0.9 at the Wigley and KCS model hull surfaces was narrowed by considering the anti-diffusion term. From the results, anti-diffusion source term decreased free-surface smearing.