• International Journal of Ocean System Engineering
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• 제2권4호
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• pp.214-222
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• 2012

The shipbuilding process is changing due to changes in the development environment and technological requirements for military ships. This would also hold true for a submarine, because its shipbuilding process includes complicated design and construction conditions. System improvement efforts for the design and construction of military ships have continued with the goal of overcoming these conditions. At present, the Korea Navy is developing a 3,000 ton-class Korean type submarine, and its design is progressing by the introduction of a full 3D-ship CAD system. Although the 3D modeling system was introduced for effective design realization through the introduction of collaborative design and active utilization of M&S (modeling and simulation), the introduction effects are not yet generally obvious, according to the characteristics of ship design. The present paper discusses the collaborative environment for developing a submarine to enhance this. This paper proposes the architecture and data structure of a system for realizing collaborative design and discusses a case system developed on the basis of this.

• 대한조선학회논문집
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• 제46권3호
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• pp.303-312
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• 2009

Recently, requests for the accurate process planning using modeling and simulation technique are increasing in many engineering fields including shipbuilding industry. In this study, Combined DEVS(Discrete EVent System specification) and DTSS(Discrete Time System Specification) simulation kernel is developed, and an integration strategy of dynamics simulation module and graphics module is also implemented. To evaluate the efficiency and applicability of the simulation kernel and integration strategy, these are applied to the block erection simulation of offshore structures.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.122-125
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• 2008

Generally, in shipbuilding, large curved block components which have large curvature radius along various directions are used for huge ships such as LPG-vessel and oil tanker ships. Lots of the blocks are manufactured by line heating method which uses a heat source to bend the thick plate materials. The conventional forming process is entirely dependent on the experience of experts because it is done by manual method thus the curvatures and qualities are not uniform even for same part. However, it is hard to adopt the press forming process using die tool sets fur the manufacturing because of the characteristics of the industry that based on the small quantity and variety in the products. In this study, flexible forming technology using numbers of punches is investigated based on the simulation to substitute for the conventional forming method. Thick plate material model was applied to the proposed process to verify the feasibility for hull structure block forming process. The press forming processes were simulated by adopting the explicit-to-implicit sequential solution. Moreover, experiment of the flexible forming process was also conducted and its results were compared with that of simulation.

• Journal of Welding and Joining
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• 제20권4호
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• pp.534-537
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• 2002

In the various industry such as shipbuilding and automobile, etc., Al-alloys are used to reduce weight and improve economical efficiency, and they are mainly utilized in the process of Friction Stir Welding (FSW). A number of studies have been carried out on the metallurgical characteristics of friction stir welding In Al-alloys. However, research on the thermal behavior of FSW by using numerical analysis is not sufficient in the domestic and abroad. In this paper, therefore, numerical simulation was used to find out thermal behaviour of FSW by finite element method. We considered heat source that occurred by friction between tool shoulder including pin and base metal. To confirm the result of simulation, macrostructure is examined and compared after welding. The result of numerical simulation shows that Al-alloy is welded under a melting point of Al around pin by FSW.

• 대한조선학회논문집
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• 제59권6호
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• pp.393-399
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• 2022

During the ship hull design process, resistance performance estimation is generally calculated by simulation using computational fluid dynamics. Since such hull resistance performance simulation requires a lot of time and computation resources, the time taken for simulation is reduced by CPU clusters having more than tens of cores in order to complete the hull design within the required deadline of the ship owner. In this paper, we propose a method for estimating resistance performance of ship hull by simulation using a graph neural network. This method converts the 3D geometric information of the hull mesh and the physical quantity of the surface into a mathematical graph, and is implemented as a deep learning model that predicts the future simulation state from the input state. The method proposed in the resistance performance experiment of simple hull showed an average error of about 3.5 % throughout the simulation.

• 대한조선학회논문집
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• 제45권6호
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• pp.703-709
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• 2008

In the shipyard, line heating and triangle heating are two major processes for forming curved plates in various shapes. While there have been many studies on line heating, triangle heating has been rarely studied due to its complicated heating process with irregular multi-heating paths and highly concentrated heat input. As the triangle heating process is one of the most labor-consuming jobs in shipyards, it is essential to study the automation as well as improvement of triangle heating process in order to increase hull forming productivity. In this study, a pioneering attempt to simulate triangle heating was made. A circular disk-spring model was proposed for elasto-plastic analysis procedure of triangle heating and the inherent strain method was also used to analyze the deformation of plates. Simulation results were compared with those of experiments and showed good agreement. It is shown that the present approach including analysis model used in this study is effective to simulate the triangle heating for plate forming process in shipbuilding.

• 한국CDE학회논문집
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• 제18권2호
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• pp.104-112
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• 2013

Computer-based modeling and simulation (M&S) techniques have become an essential component in the development of new weapons systems. M&S techniques provide a means to simulate military training, strategies, military doctrines, and weapons acquisition processes. This paper proposes a small scale engagement scenario generation method. This work also includes a process for scenario generation and visualization. The proposed scenario generation methodology employs the Timed-FSA (finite state automata) and DFS (depth first search) algorithms. The proposed scenario generation method is verified using a one-on-one combat engagement scenario between two submarines. In addition, we suggest a scenario generation process including whole scenario generation and scenario visualization.

• 소성∙가공
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• 제22권4호
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• pp.196-203
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• 2013

Flexible stretch forming is an appropriate process for manufacturing of components for aerospace, shipbuilding and architecture structures. Flexible stretch forming has several advantages including that it could be applied to form various shapes such as ones with double curved surfaces. In this study, a systematic numerical simulation was conducted for forming double curved surfaces using flexible stretch forming. The desired surface had a saddle type configuration. It had two radii one of 2500mm and the other of 2000mm along its length and width. In the simulation, the decrease of elastic recovery due to the stretching was confirmed. Experiments were also conducted to confirm the viability of the process. By comparing the simulation to the experiment results, the suitability of flexible stretch forming for double curved surfaces was verified. From the results, the maximum error from desired surface was confirmed at about 1.3mm at the edge of the surface. Hence, it is confirmed that flexible stretch forming has the capability and feasibility to manufacture curved surfaces for architectural skin-structures of buildings.

• 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.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2001년도 추계학술대회 논문집
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• pp.286-289
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• 2001

This paper deals with the procedures of effective mid-term Operation Planning establishment for painting shop in shipbuilding. and develop prototype system. In general, the block painting process consists of two stages such as blasting operation for surface preparation and painting operation for paint application for blocks. Weather condition is a potent Influence on those operations. The procedures consists of four steps, Load analysis, Generate alternative simulation plan. Implementation of Allocation automation module and Compare result of each simulation plan. Explain of each step. as follows, 1.step, Load analysis measure amount of assigned workload and manhour. 2.step, simulation scheme include alterable control variable such as overtime, weather. Auto allocating module carry out feasibility of simulation plan. 3.step, Allocation automation module are composed of three algorithms, as followings: - the block allocation algorithm that determines the number of blocks to be processed each day, - the team allocation algorithm that allocates blocks to worker groups. - the block arrangement algorithm that arrange blocks in blasting and painting cells. Since the block arrangement algorithm is conducted simultaneously with the team allocation algorithm, the total structure of the operating algorithms is considered to have two phases: first, daily load balancing with capacity limit and second, team allocation considering arrangement each day 4 step, Comparing result of each simulation plan. and select best simulation plan.