• 대한조선학회 특별논문집
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• 대한조선학회 2007년도 특별논문집
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• pp.99-106
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• 2007

The IACS Common Structural Rules are to be applied for double hull tanker of more than 150m length with contracted after 1 April 2006. The objectives of the rules are to make more robust, safer ship and to ensure transparency of the technical background. In compliance of CSR, we had carried out prescriptive rules scantling determination and 3-D hold FE analysis of AFRAMAX TANKER. Prescriptive rules scantling determines the minimum required scantling, hull-girder longitudinal bending and shear strength, hull girder ultimate strength, local strength of plate and stiffener, strength of primary supporting member and fatigue assessment of the longitudinal stiffener end connections to the transverse bulkhead. 3-D hold FE analysis assesses the structural adequacy of the vessel's primary hull structure and major supporting members using yielding and buckling failure modes. So we could verify the strength assessment of AFRAMAX TANKER applied CSR.

• Ocean Systems Engineering
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• 제1권3호
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• pp.223-239
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• 2011

In combat operations, naval ships may be subjected to considerable air blast and underwater shock loads capable of causing severe structural damage. As the experimental study imposes great monetary and time cost, the numerical solution may provide a valuable alternative. This study emphasises on numerical analysis for optimization of stiffened and unstiffened plate's structural response subjected to air blast load. Linear and non linear finite element (FE) modeling and analysis was carried out and compared with existing experimental results. The obtained results reveal a good agreement between numerical and experimental observations. The presented FE models can eliminate confusion regarding parameters selection and FE operations processing, using commercial software available currently.

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.123-129
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• 2009

Ship painting procedures can be divided into two categories; Out-shell plate painting of the hull and the interior painting of each double gull blocks. It is really hard to apply standardized and automated operations to the latter because the double hull blocks contains a variety of complicated supportive materials and pipes to strengthen the ship structure. In addition their poor working conditions cause painting workers to avoid working in them, resulting in the waste of paints and additional pollution issues. So this research, successfully focused on overcoming the difficulties in working in the complicated blocks and the tough working conditions introduces the main details of automatic equipment systems and their transfer algorism which show how the equipment paints the inner sides of a longitudinal stiffener and moves to another automatically.

• 대한조선학회논문집
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• 제53권5호
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• pp.400-409
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• 2016

In recent, shipping companies have made an enormous effort to improve the operation of vessel in various approaches, due to recession of shipping market and increasing competition among shipping companies. One of important parameters for improving the efficiency of vessel is the resistance performance that consist of friction and residual resistance. Especially, it is recognized that the friction resistance tends to be affected by conditions of vessel’s surface and occupies approximately 70~90% of the total resistance for slow speed ships. In general, the surface of vessel is covered with various type of paint to reduce fouling and corrosion. As time goes by, however, it is so hull roughness would be increased by fouling over the wetted surface that anti-fouling paints, such as CDP(Controlled Depletion Paint), Tin-Free SPC(Self Polishing Co-polymer) or Foul Release, are applied evenly on the hull surface. Nevertheless, these anti-fouling paints could not prevent fouling absolutely. A fundamental study on evaluating ship resistance performance variation due to hull roughness has been performed using a commercial software, Star-CCM+, which solves the continuity and Navier-Stokes equations for incompressible and viscous flow. The results of present simulation for plate are compared with some experimental data available and the effect of surface roughness to ship resistance performance is discussed.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 제 25회 정기총회 및 추계학술발표회
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• pp.51-58
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• 2000

The purpose of this study is the optimum modification of dynamic characteristics of stiffened plate structure. In the method of the optimization ,finite element method (FEM), sensitivity analysis and optimum structural modification method are used. To begin with, using FEM, the dynamic characteristics of stiffened plate structure is analyzed. Next, rate of change of dynamic characteristic by the change of design variable is calculated using the sensitivity analysis. Then, amount of change of design variable is calculated using this sensitivity value and optimum structural modification method. The change of natural frequency is made to be an objective function. Thickness of plate and cross section moment become a design variable. It is shown that the results are effective in the optimum modification for dynamic characteristics of the stiffened plate structure.

• 한국소음진동공학회논문집
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• 제23권5호
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• pp.394-400
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• 2013

Underwater radiated noise is one of the important performances related to stealth of the naval vessel. However, the evaluation can't be performed frequently due to the cost. Therefore, the estimation method of the underwater radiated noise with average hull vibration is suggested in this paper assuming that the hull of the ship is infinite plate which consists of various unit plates. Through the experiment, the estimated noise is verified from the comparison to the measured data. In addition the difference of underwater radiated noise according to the operating equipments is estimated with measured vibration velocity.

• 대한조선학회논문집
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• 제46권6호
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• pp.587-594
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• 2009

In the paper the effect of a stern-plate attached to a ship was taken into account. The relationship between the trim angle of a ship and the wave-resistance coefficient induced by the a stern-plate was studied using the potential flow analysis method. Numerical algorithm was described using the panel method and the vortex lattice method(VLM) to simulate the flow phenomena around a ship. The non-linearity of the free surface boundary conditions were considered using the iterative method and the IGE-GMRES(Incomplete Gaussian Elimination-The Generalized Minimal RESidual) algorithm was adopted to solve the linear equation at each iterative step. Numerical calculations were carried out to investigate the validity of the adopted algorithm using KCS(KRISO 3600 TEU Container) hull. Possible cases for attachment of the plate were checked. The results showed that the numerical algorithm could be physically appropriate.

• 해양환경안전학회지
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• 제26권2호
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• pp.219-226
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• 2020

선체구조의 품질검사 중 가장 일반적인 방법의 하나는 비파괴검사이다. 하지만 복합소재 선체는 강화재와 수지로 구성된 여러가지 재료가 섞여 있고 또 생산환경과 작업자에 따라 FRP(Fiber-Reinforced Plastics) 제작품질에 차이가 발생할 가능성이 크기 때문에 정확한 검사평가는 쉽지 않은 일이다. 특히 FRP 선박의 경우에는 다른 구조물보다 두께가 매우 두껍고 주로 수척층 공법을 이용하기 때문에 더욱 그렇다. 초음파 탐상의 조건 중 검사체의 밀도가 매우 중요하기 때문에 본 연구에서는 FRP 선박 제작에 널리 사용되고 있는 소재와 유리섬유강화재 중량 비율로 제작된 선박의 외판을 검사체로 선정하고, Pulse-Echo 초음파 탐상기를 활용하여 GFRP(Glass Fiber-Reinforced Plastics) 선체 외판의 초음파 탐상을 위한 적정 조건을 조사하였다. 1.00 MHz, 2.25 MHz, 5.00 MHz 세 종류 탐촉자로 A-Scan을 실시하였으며 선체 외판의 두께 검사결과와 비교분석함으로써 적정 초음파 탐상 조건을 찾고자 하였다. 연구결과 탐촉자의 초음파 주파수가 높아질수록 수신자의 반사파 음향 속력을 감소시켜야 더 정도 높은 두께 측정 결과를 얻을 수 있었으며, 상대적으로 낮은 초음파 주파수 탐촉자에서 더 적은 오차가 발생함을 확인할 수 있었다.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4381-4387
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• 2015

선체의 외판은 복잡한 곡면 형상이며 대부분의 조선소에서는 이의 제작을 위해 가스 토치를 이용한 선상 가열 방법을 사용하고 있다. 가스 토치를 이용한 전통적인 선상 가열 방법은 입열량의 제어가 어려울 뿐만 아니라 고압의 가스 분출에 따른 소음과 대기 오염 등 열악한 작업 환경의 문제점을 안고 있다. 최근에는 입열량의 제어가 비교적 용이하고 친환경적인 고주파 유도 가열에 주목하여 이를 가열 열원으로 하는 강판의 성형 자동화 연구들이 진행되고 있다. 본 연구에서는 강판의 곡면 성형을 위한 유도 가열 시뮬레이션 방법을 개발하였으며 유도 가열 실험 결과와 비교하여 그 유효성을 검증하였다. 개발된 유도 가열 시뮬레이션 방법은 효율적인 유도 가열 코일 설계와 최적 성형 조건 산출 등 유도 가열을 이용한 선체 외판의 곡가공 자동화 시스템 개발에 유용한 해석적 툴로 활용될 수 있을 것으로 기대된다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.214-220
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• 1998

The determination of sound pressure radiated from periodic plate structures is fundamental in the estimation of noise levels in aircraft fuselages and ship hull structures. As a robust approach to this problem, here a very general and comprehensive analytical model for prediction the sound radiated by a vibration plate stiffened by periodically spaced orthogonal symmetric beams subjected to a sinusoidally time varying point load is developed. The plate is assumed to be infinite in extent, and the beams are considered to exert both line force and moment reactions on it. Structural damping is included in both plate and beam materials. From this theoretical model, the sound pressure levels on axis in a semi-infinite fluid(water) bounded by the plate with the variation in the loactions of an external using three numerical tools such as the Gauss-Jordan method, the LU decomposition method and the IMSL numerical package.