• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1998년도 특별강연 및 추계학술발표 개요집
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• pp.3-8
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• 1998

This paper considers factory simulation based on shipbuilding CIM in which a computer integrated design and manufacturing system is considered. The author proposes the product model and several alterative functions for designing ship's structure, and develop a ship definition system for computer integrated design and manufacturing. This implemented system is called SODAS (System Of Design and Assembly for Shipbuilding). Object oriented concept is used to develop this system. As well as the product model, the design function cutting function, and virtual assembling function are introduced. By using the design function, any type of ship's structure can be designed. And also factory simulation can be carried out by using the cutting function and virtual assembling function.

• 대한조선학회논문집
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• 제53권2호
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• pp.101-107
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• 2016

Generally, the shipbuilding industry has finite resources and limited workspace. Due to finite resources, limited workspace and state of block preparation, erection process in shipbuilding industry is frequently delayed than erection process scheduling which is planned at long-term plan stage. In this study, considering variability of block reserve ratio, the degree of delay in real erection process is measured and compared to scheduling which is planned at long-term plan stage in shipbuilding industry including finite capacity and variative lead time. Also, the erection process scheduling which has minimum lead time can be checked through simulation. The results of this study could be improved the accuracy of erection process scheduling by checking the main event compliance ratio by block reserve ratio and calculating the optimum erection pitch for the main event compliance.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.294-306
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• 2019

On the basis of the Computational Fluid Dynamics technique (CFD) combined with the overlap grid method, this paper establishes a numerical simulation method to study the problem of ice-propeller interaction in viscous flow and carries out a simulation forecast of the hydrodynamic performance of an ice-class propeller and flow characteristics when in the proximity of milling-shape ice (i.e., an ice block with a groove cut by a high-speed revolving propeller). We use a trimmed mesh in the entire calculation domain and use the overlap grid method to transfer information between the domains of propeller rotation calculation and ice-surface computing. The grid is refined in the narrow gap between the ice and propeller to ensure the accuracy of the flow field. Comparison with the results of the experiment reveals that the error of the hydrodynamic performance is within 5%. This confirms the feasibility of the calculation method. In this paper, we calculate the exciting force of the propeller, analyze the time domain of the exciting force, and obtain the curve of the frequency domain using a Fourier transform of the time-domain curve of the exciting force. The existence of milling-shape ice before the propeller can greatly disturb the wake flow field. Unlike in open water, the propeller bearing capacity shows a downward trend in three stages, and fluctuating pressure is more disordered near the ice.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.414-427
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• 2020

The finite element method is used to simulate the navigation of an ice-area bulk carrier in broken ice fields. The ice material is defined as elastic, and the simulations are accomplished at four model speeds and three ice concentrations. The movements of ice floes in the simulation are consistent with those in the model test, and the percentage deviation of the numerical ice resistance from the ice resistance in the model test can be controlled to be less than 15 %. The key characteristics of ice loads, including the average ice loads, extreme ice loads, and characteristic frequency, are analyzed thoroughly in a comprehensive manner. Moreover, the effects of sailing speed and ice concentration on the ice loads are analyzed. In particular, the stress distribution of ice floes is presented to help understand how model speed and concentration affect the ice loads. The "ice pressure" phenomenon is observed at 90 % ice concentration, and it is realistically reflected both in the time―and frequency―domain ice force curves.

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.107-114
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• 2009

In the recent large block are used to build the ship to improve productivity. For this reason, two or more floating cranes that are connected in parallel is the trend. Typically, when working with floating crane load safety factor is considered. Even in the parallel operation, load safety factor is calculated similar to working alone. For this reason, operations do not guarantee the reliability or excessive safety factor applied. Therefore, the subdivided cases for calculating the safety factor are defined when parallel connected floating cranes are operated. Based on those cases, the operation standard is made about procedure using parallel connected floating cranes. And to verify this, dynamics simulation was performed for verification using the dynamics simulation program.

• 대한조선학회논문집
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• 제52권4호
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• pp.330-337
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• 2015

When a tower crane is carried by a transporter in shipyard, the height and length of the tower crane should be adjusted to meet the safety guidelines. Since the guidelines came from the field experience, the safety limitation needs to be analyzed by a computer simulation. In this paper, modeling methods are addressed to implement the appropriate transportation simulation of a tower crane. For the relation between the tower crane and the transporter, normal contact force, friction force, and kinematic constraints are compared. Assignment of relevant linear acceleration and angular velocity is considered for the transporter to start or move on an inclined ground surface. By using the examined modeling methods, the dynamic motion of tower crane transportation is analyzed by a dynamic simulation program, and comparison between the simulation result and analytic solution is made to verify the feasibility of the modeling methods.

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.127-132
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• 2011

In this paper, hydrodynamic performance of FSRU which is designed to operate in North America East Coast assessed. In order to estimate the dynamic performance, the numerical analysis is carried out based on a time domain simulation program to solve the coupled dynamics for floater and mooring lines which is as well known program as DNV SESAM package. The target operating area is East coast of North America and the model test was carried out based on the meta-ocean data of the area. The mooring analysis is only considered wave without other environment condition at this time. The results of the numerical analysis show the under-estimated results at the higher wave height condition. But the tendency is very similar. Also, the motion response show good agreement compared with model test.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권2호
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• pp.471-483
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• 2014

Since 2009 of global financial crisis, shipbuilding industry has undergone hard times seriously. After such a long depression, the latest global shipping market index shows that the economic recovery of global shipbuilding market is underway. Especially, nations with enormous resources are going to increase their productivity or expanding their shipyards to accommodate a large amount of orders expected in the near future. However, few commercial projects have been carried out for the practical shipyard layout designs even though those can be good commercial opportunities for shipbuilding engineers. Shipbuilding starts with a shipyard construction with a large scale investment initially. Shipyard design and the equipment layout problem, which is directly linked to the productivity of ship production, is an important issue in the production planning of mass production of ships. In many cases, shipbuilding yard design has relied on the experience of the internal engineer, resulting in sporadic and poorly organized processes. Consequently, economic losses and the trial and error involved in such a design process are inevitable problems. The starting point of shipyard construction is to design a shipyard layout. Four kinds of engineering parts required for the shipyard layout design and construction. Those are civil engineering, building engineering, utility engineering and production layout engineering. Among these parts, production layout engineering is most important because its result is used as a foundation of the other engineering parts, and also, determines the shipyard capacity in the shipyard lifecycle. In this paper, the background of shipbuilding industry is explained in terms of engineering works for the recognition of the macro trend. Nextly, preliminary design methods and related case study is introduced briefly by referencing the previous research. Lastly, the designed work of layout design is validated using the computer simulation technology.

• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.90-93
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• 2013

RAM study has been used for various range of industry such as chemical, electronics, defense industry. Recently, in the offshore & shipbuilding industry, demand of owners to analysis risk has been increased. RAM study is a quantitative pointer to risk based design and provides effective method for improvements. This article shows the result of RAM study for LNG fuel supply system. The result provides information to improve design. This study shows how result of risk assessment affects the design of LNG fuel supply system.

• 산업공학
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• 제18권2호
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• pp.167-177
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• 2005

As the largest shipbuilding company in the world and the leader in the Korean merchant shipbuilding industry, Hyundai Heavy Industries is currently struggling to carry out intensive productivity improvement efforts in order to be the global merchant shipbuilding market leader by surpassing in the competition with Japan and being free from the defiance of China armed with very cheap labor costs. This paper introduces the academy-and-industry collaborative project, a part of the productivity improvement efforts, which has conducted on the steel stockyard operations. As a pilot project that researches for the way of improving the stockyard operations and ignites further projects on the stockyard operations, the project defined the stockyard operations, measured current situations, and analyzed management dilemmas. In addition, the project developed the steel stockyard operations simulator. Besides that the simulator is used by the operations manager who has heavily relied on his work-experienced intuition when making decisions, this paper expects that further projects on the stockyard operations utilize the simulator for their own purposes.