• 한국해양공학회지
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• 제34권2호
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• pp.97-109
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• 2020

In this study, ultimate strength characteristics of clamped sandwich panels with metal faces and an elastic isotropic core under combined in-plane compression and lateral pressure loads are investigated to verify the applicability of the ultimate strength design formula for ship structures. Alternative elastomer-cored steel sandwich panels are selected instead of the conventional bottom stiffened panels for a Suezmax-class tanker and then the ultimate strength characteristics of the selected sandwich panels are examined by using nonlinear finite element analysis. The change in the ultimate strength characteristics due to the change in the thickness of the face plate and core as well as the amplitude of lateral pressure are summarized and compared with the results obtained by using the ultimate strength design formula and nonlinear finite element analysis. The insights and conclusions developed in the present study will be useful for the design and development of applications for sandwich panels in double hull tanker structures.

• 한국해양공학회지
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• 제33권2호
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• pp.146-152
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• 2019

A design system was developed for the doubler plate of a ship structure simultaneously subjected to in-plane loads and lateral pressure based on general dimensions and those of a representative ship structure. An equivalent design equation that considers various structural design parameters was derived by introducing the equivalent plate thickness theory, and the design of the doubler plate reinforcement of the ship structure was developed. A hybrid structural design system was established for a doubler plate simultaneously subjected to in-plane loads and lateral pressure consisting of two modules: an optimized design module and a double plate strength & design review module. The practical application of this design system was illustrated to show its usability. It was found that the design safety of the doubler plate was ensured, and this system could be used as an initial design guide to review the double plate reinforcement for a dent or corrosion of the ship plate members. Using the developed design system would make it possible to obtain a more reasonable doubler plate structure that considers the rational reinforcement of plate members of ship structures. In addition, a more reliable structural analysis using a strength evaluation process can be performed to verify the efficiency of the optimum structural design for the doubler plate structure.

• 한국항해학회지
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• 제7권1호
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• pp.63-81
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• 1983

A vessel encountered heavy weather is face to two kinds of danger ; the danger of upset due to the lack of stability and the lack of the longitudinal strength. Generally a small vessel is face to the former and the large vessel to the latter. Most of people do not consider the danger of upset by the latter but the former. But many ships missed at sea, the exact causes being not known. This pper investigated and analyzed the causes of accidents. The result was that the lohgitudinal strength of the hull is not enough to cope with heavy weather, and the particular cautions are needed to handle a ship in heavy weather.

• 선박안전
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• 통권21호
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• pp.4-14
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• 2006

Marine diesel engine production and refinements sought a continuous increase on mean effective pressure and thermal efficiency. These results in increased maximum combustion pressure within the cylinder and vibratory torque in crankshaft. As such, crankshaft should be designed and compacted within its fatigue strength. In this paper, the 8H25/33P(3,155ps 900rpm) engine for ship propulsion was selected as a case study, and the strength analysis of its crankshaft is carried out by: simplified method recommended by IACS M53 and a detailed method with the crankshaft assumed as a continuous beam and bearing supported in its flexibility. The results of these two methods are compared with each other.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.262-269
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• 2004

Ship structures are basically an assembly of plate elements and the load-carrying capacity or the ultimate strength is one of the most important criteria for safety assessment and economic design. Also, Structural elements making up ship plated structures do not work separately, resulting in high degree of redundancy and complexity, in contrast to those of steel framed structures. To enable the behavior of such structures to be analyzed, simplifications or idealizations must essentially be made considering the accuracy needed and the degree of complexity of the analysis to be used. On this study, to investigate effect of analysis range, the finite element method are used and their results are compared varying the analysis ranges. The model has been selected from bottom panels of large merchant ship structures. For FEA, three types of structural modeling are adopted in terms of the extent of the analysis. The purpose of the present study is to numerically calculate the characteristics of ultimate strength behavior according to the analysis ranges of stiffened panels subject to uniaxial compressive loads.

• 대한조선학회논문집
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• 제34권2호
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• pp.75-84
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• 1997

본 연구에서는 스펙트럼 해석법에 기초한 새로운 개념의 정밀한 선체구조 피로강도평가 시스템을 개발하였으며 membrane 방식 LNG 운반선을 대상으로 하여 수치계산을 수행함으로써 그 효용성을 검증하였다. 선체에 작용하는 파랑하중을 스트립 이론으로 직접계산하고 3차원 정밀 구조해석과 영향계수 개념을 바탕으로 Miner 법칙에 의한 누적손상도를 계산하여 설계기준과 비교, 검토하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제4권2호
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• pp.132-140
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• 2012

This study aims to assess fatigue property by the static overload and average load in the fillet welded joints which is on the ship structural steel having gusset welds. To this end, a small specimen was made, to which the same welding condition for the actual ship structure was applied, to perform fatigue tests. In this study, a method to simply assess changes in welding residual stress according to different static overload was suggested. By measuring actual strain at the weld toe, the weld stress concentration factor and property which is determined by recrystallization in the process of welding were estimated to investigate the relation between overload and fatigue strength.

• 대한조선학회논문집
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• 제32권1호
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• pp.25-36
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• 1995

확률적인 접근법으로서의 신뢰성 해석법의 소개와 이의 선체 구조 강도 평가 방법에의 적용에 관해 고찰하였다. 당사에서 건조한 유조선 및 살물선 34척을 대상으로 인장 항복강도, 보강판의 압축 최종강도, 그리고 선각 거어더의 최종강도 등 몇몇 대표적인 종강도 파괴양식에 대해 신뢰성 해석을 수행하였다. 해석결과로서 각 선박에 대한 신뢰도 지수를 보이고 종강도에 대한 신뢰성 해석시의 목표 신뢰도 지수를 제시하였다. 배길이와 건조연도에 따른 신뢰도 지수의 변화를 검토하였으며 결과로서 각 선박의 안전도가 큰 차이를 보임을 알 수 있었다. 각 선박에 대해 균일한 수준의 신뢰도를 제공하기 위하여 부분 안전계수를 이용한 새로운 강도 평가 기준을 마련하였다. AFOSM 방법 및 신뢰성 조건(RC) 방법에 따라 부분 안전계수를 계산하고 이를 비교하였으며 원하는 신뢰도를 줄 수 있는 설계식을 RC 방법으로 구하였다. 부분 안전계수로부터 구한 새로운 설계식을 사용하여 신뢰성 해석을 수행한 선박에 대해 재해석을 실시하였다. 그 결과 처음보다 많이 개선된 균일한 수준의 신뢰도를 얻을 수 있었고 이로부터 신뢰성 해석의 적용가능성과 유용성을 확인하였다.

• 해양환경안전학회지
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• 제23권1호
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• pp.40-46
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• 2017

본 연구는 LS-DYNA 971 을 이용하여 내빙 구조 선박과 빙산 모형 간의 충돌 시험을 수행 후 북극해 운항 선박의 내빙 능력을 분석하였다. 국제선급연합회(IACS)의 Unified Requirements for Polar ship(URI) 규정을 바탕으로 FEM 선박 모형에 내빙 구조를 적용하였으며, 빙산 모형에는 Elastic-perfect plastic 물성과 Tsai-Wu 항복 곡면을 적용하였다. 또한 실험 결과 비교를 위하여 내빙 구조를 갖추지 않은 일반선박 모형과의 충돌 시험도 수행하였다. 실험 결과 일반 구조 선박의 구형 선수에 빙산 모형에 의해 움푹 들어간 약 1.8 미터 깊이의 선체 손상이 발생하였으나, 내빙 구조 선박의 충돌에서는 약 1.0 미터 깊이의 선체 손상만이 발생하였다. 또한 일반 구조 선박과 충돌한 빙산모형은 원형의 상태를 거의 유지한 반면, 내빙 구조 선박과 충돌한 빙산 모형은 내빙 구조의 구형 선수에 의해 빙산이 일부 파괴되는 현상이 발견되었다.

• 대한조선학회논문집
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• 제40권6호
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• pp.30-36
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• 2003

To improve survivability of damaged ship, assessment of stability and structural safety, and behavior analysis in wave is required. Prediction of sinking time, damage stability and structural strength considering progressive flooding and dynamic force in wave is very important. To do it, a geometric model which can be express damaged ship is prepared. This paper described the geometric modeler for survivability assessment of damaged ship. The modeler is developed based on 3-D geometric modeling kernel, ACIS. The hull form and compartment definition is available fundamentally. And requirement for modeler contains data generation and interface for hydrostatic calculation, behavior analysis, and longitudinal strength analysis and so on. To easy access modeling system by conventional user such as crew, user interface is developing.