• 대한조선학회지
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• 제20권2호
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• pp.21-26
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• 1983

In this light of economical engineering, the optimal configurations of ship structure that can save weights, production costs and operation costs should be investigated. This paper presents the general method of optimization based on non-linear programming and its application to weight and/or cost minimization of ship structure. Oil tanker is chosen as a ship type because of simple layout and easy calculation of stress. With the data of 16,200 DWT oil tanker built by KSEC 1980, this paper shows the procedure mentioned above by means of SUMT combined with two selected search methods. Then the differences between original and redesigned tanker structures are discussed.

• 대한조선학회지
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• 제26권3호
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• pp.62-70
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• 1989

선체와 같이 복잡 대형 구조물에 대하여 유한요소법 등의 직접구조해석을 통한 최적설계를 수행하는 데에는 반복적인 구조해석으로 인한 막대한 계산량의 처리가 매우 심각한 문제로 대두된다. 본 연구에서는 이러한 반복구조해석에 소요되는 계산시간을 절감하기 위하여 최적구조설계 과정에 기저축소에 의한 재해석기법을 적용하여 보았고, 또한 본 설계기법을 간단한 격자구조물과 실제적인 선체의 최소중량 설계 문제에 적용함으로써 그 유용성과 정도를 확인하였다.

• Journal of Hydrospace Technology
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• 제2권1호
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• pp.18-26
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• 1996

It is normal practice to consider bending wave modes only, when one applies SEA (Statistical Energy Analysis) to ship structures because of complexities in SEA modeling and evaluation of coupling loss factors for inplane modes. According to the result of Tratch[1], the inplane wave modes becomes important for the analysis of a foundation structure as the distance from the source and receiver increases. In this paper, the effect of inplane wave modes on structure-borne noise propagation in ship structures is presented. It is shown that the inplane wave could increase the noise level more than 10 dB compared with the results without inplane wave modes at high frequency bands for compartments far from the source location.

• 대한조선학회논문집
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• 제54권1호
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• pp.34-42
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• 2017

In rough seas, green water shipped on board may impose quite large impact loads on the structures on deck and sometimes result in structure damages. One of the essential tasks of the naval fluid engineers is to provide the design impact loads which are needed for proper design of the structure strength against the green water impacts. Computation of the design impact load due to green water needs first a process to find the sea condition and the ship cruising condition which cause maximum green water impacts on structures as well as other succeeding processes to compute ship motion responses, green water flows and impact loads. Also, as a bold and practical process, it is needed that the irregular real seas are to be substituted by design regular waves which are equivalent in view points of green water impacts. In this paper, the whole processes to compute the design green water loads acting on bow structure are set up creatively. And the green water design impact loads acting on the box-type structure of a high-speed ship's bow are computed and discussed.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권2호
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• pp.459-470
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• 2014

During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

• Structural Engineering and Mechanics
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• 제50권6호
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• pp.835-852
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• 2014

Despite the availability of other transport methods such as land and air transportations, marine transportation is the most preferred and widely used transportation method in the world because of its economical advantages. In service, ships experience cyclic loading. Hence, it can be said that fatigue fracture, which occurs due to cyclic loading, is one of the most critical failure modes for vessels. Accordingly, this makes fatigue failure prevention an important design requirement in naval architecture. In general, a ship structure contains many structural components. Because of this, structural modeling typically relies on Finite Element Analysis (FEA) techniques. It is possible to increase fatigue performance of the ship structures by using FEA in computer aided engineering environment. Even if literature papers as well as rules of classification societies are available to assess effect of fatigue cracks onto the whole ship structure, analytical studies are relatively scarce because of the difficulties of modeling the whole structure and obtaining reliable fatigue life predictions. As a consequence, the objective of this study is to improve fatigue strength of a mercantile vessel against fatigue loads via analytical method. For this purpose, the fatigue life of the mercantile vessel has been investigated. Two different type of fatigue assessment models, namely Coffin-Manson and Morrow Mean stress approaches, were used and the results were compared. In order to accurately determine the fatigue life of the ship, a nonlinear finite element analysis was conducted considering plastic deformations and residual stresses. The results of this study will provide the designer with some guidelines in designing mercantile vessels.

• Ocean and Polar Research
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• 제23권2호
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• pp.63-75
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• 2001

Species composition and community structure of the fouling found on the hulls of 28 ships traveling through 6 main shipping routes (SR)in the Far East Sea Basin were analyzed using statistical methods. Samples obtained during 1976-1990 expeditions of the Institute of Marine Biology were used for the analyses. These samples were taken from the ships anchored in the harbor by SCUBA diving and in dry-docks of the Vladivostok ship-repairing yard. Similar composition of the fouling communities occurred on the ships travelling the same SR. In five cases, fouling was dominated by different Cirripedia communities. And, in one case, a community of the mussel Mytilus trossulus was found. In most cases the results of the factor analyses showed extremely low level of the relationships among different animals and algal species in fouling communities. Each ocean-going ship had an original structure of the fouling. Spatially disconnected animal associations of tropical and boreal origin may simultaneously coexist at the same ship. This paper testified to the originality of the zone of anthropogenic substrata as a benthos concentrator in the pelagic regions of the world ocean. The fouling from different zones showed that each zone possesses peculiar features and regularities of the composition and relationships between organisms dwelling here.

• 한국재난정보학회 논문집
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• 제7권1호
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• pp.75-85
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• 2011

본 논문에서는 파일형 선박충돌방호공에 선박이 충돌하였을 때 거동을 해석하였다. 충돌방호공은 슬래브, RCP말뚝 및 이를 지지하는 지반을 비선형스프링으로 모델링하였다. 선박의 선수는 탄소성거동을 하는 쉘요소로 모델링하였으며, 선체부는 충격 시 변형이 크게 발생하지 않으므로 선형재료로 고체요소를 이용하여 모델링을 하였다. 선박의 중량의 변화에 따른 거동특성을 파악하기 위해 선박의 질량을 DWT 10000 부터 DWT 25000까지 5000씩 증가시켜 해석을 수행하였다. 또한 선박과 방호공의 충돌은 정면충돌로 고려하였으며, 충돌 속도는 5knot로 가정하였다. 선박과 방호공과의 충돌 해석은 비선형 해석 프로그램인 ABAQUS/Explicit을 이용하여 수행하였으며, 이를 통하여 선박 충돌 시 방호공의 에너지 거동을 분석하였다. 해석결과 선박의 중량이 증가할수록 선수와 슬래브의 변형에 의한 소성 소산 에너지량이 증가하는 것을 확인할 수 있었다.

• 건축역사연구
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• 제31권6호
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• pp.7-16
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• 2022

Traditional Korean architecture and traditional ships maintained a close relationship with carpenters and tools because wood, the material, was common. This close relationship may have been from the time of ancient architecture and ancient ships. In previous studies, researchers proved the relationship between these two sides through historical records of traditional architecture and traditional ships. This study attempts to prove the structural association using existing remains. As a result, three structural similarities between traditional architecture and traditional ships could be found. First, the types of wood used are similar, and the tools and terms used are similar. Second, the method of distinguishing horizontal and vertical materials and the structure of wood and the method of forming wood are similar. Lastly, the ship carpenters mobilized for the construction of the palace mainly worked on long and curved materials such as the eaves and the ridge of a roof, because this was the work done when the ship was built. Therefore, it can be assumed that the roof structure they created resembles that of the ship.

• 대한조선학회논문집
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• 제33권1호
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• pp.173-181
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• 1996

본 논문은 조선공업에 동시공학 개념을 적용하기 위한 것으로 선박 구조설계 및 모델링을 대상으로 한 것이다. 본 연구에서는 선박의 구조부재를 모델링하기 위한 방법으로서 범용 CAD시스템의 사용자 정의 언어(PPL, Parametric Programming Language)를 이용하는 방법과 이를 이용한 parametric macro를 이용하는 것을 제안하였다. 한편 모델링의 효율성 및 그 결과의 활용성을 고려하여 모델링 절차에 대하여 검토하였으며 각각의 모델링 절차들이 갖는 장단점을 비교하였다. 마지막으로 구조부재의 모델링 결과를 어떻게 활용하는가에 대하여 간략히 설명하였다.