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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Society of Naval Architects of Korea
Journal Basic Information
Journal DOI :
The Society of Naval Architects of Korea
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Volume & Issues
Volume 38, Issue 4 - Nov 2001
Volume 38, Issue 3 - Aug 2001
Volume 38, Issue 2 - May 2001
Volume 38, Issue 1 - Feb 2001
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Numerical and Experimental Simulation of Directional Waves in Towing Tank
Y.K. Chung ; J.H. Lee ; H.H. Chun ; D.D. Ha ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 1~9
Based on the linear potential theory with the side wall reflection. the directional spectrum waves are numerically simulated by a source distribution method and these together with long-crested irregular waves are also generated at the towing tank of Pusan National University by considering the transfer function of the wave maker obtained from the regular waves. In the numerical simulation, the characteristics of the directional spreading function are investigated by changing the breadth of the wave-maker unit. the width of the towing tank and the wave period. In the experimental generation, the statistical properties and the power spectrums of the long-crested irregular and directional waves are compared along the towing tank length. The directional spreading functions are also investigated at various positions in the tank.
Motion Analyses for a Very Large Floating Structure with Dolphin Mooring Systems in Irregular Waves
H.Y. Lee ; H. Shin ; C.G. Lim ; O.H. Kim ; J.M. Kang ; M.C. Yoon ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 10~18
The very large floating structure which can be used for as airport may be as large as several kilometer long and wide. The first order wave forces as well as wave drift forces are very important forces on such a very large floating structures. In the present study, the time simulation of motion responses for dolphin-moored VLFS in waves is presented. The hydrodynamic coefficients and wave forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The horizontal drift forces and mooring forces for dolphin systems are taken into account. As for numerical example, time domain analyses are carried out for a VLFS(Phase I) in irregular wave condition.
A study for the structural design of floating airports on sea
Seong-Whan Park ; Tae-Young Chung ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 19~25
Structural design requirements for very large floating structures(VLFS) are different corresponding to this purpose and structural type. In this study, the structural design procedure of VLFS is described, composing of the following processes : construction of design conditions. choice of structural types and main materials, estimation of structural design loads, determination of structural arrangements, and scantling of structural members. As an example of practical application, the initial structural design of floating airport and container terminal for Pusan is demonstrated.
Hydroelastic Responses for a Very Large Floating Structure with a Breakwater
H.Y. Lee ; H. Shin ; C.G. Lim ; O.H. Kim ; J.M. Kang ; M.C. Yoon ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 26~32
In this paper, elastic responses of a floating structure in waves with a breakwater are presented. The method of source-dipole distribution is used to analyze the velocity potentials for the fluid region. The deflections of structure are expanded approximately in terms of natural mode functions of free-free beam. The model for present calculation is a floating plate with an length of 1000m and the hydroelastic responses for a floating structure with a straight breakwater are shown. The effects of distance between breakwater and structure, bending rigidity and relative length of regular waves are examined.
An Experimental Method of Model Installed Dynamic Positioning System for Drillship
Dong-Yeon Lee ; Mun-Keun Ha ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 33~43
The design and construction of special purpose vessels such as drillship and shuttle tankers have been increased. These vessels install the DPS(dynamic positioning systems) to maintain the position and heading for long-time operation. This paper deals with the experimental method for model-based DP system and the control theory and filter algorithms. In this experiment, the length of model ship is 4 meters and it has three thrusters to maintain the position. The ability of tracking along the given course and keeping of heading in waves are confirmed. For the calculation of thruster input the PID control theory are adopted and the effects of PID gain were investigated. To estimate the low frequency motions Kalman filter and digital filter were used and their effects were investigated.
Structural Analysis and Towing Test for Predicting Drag Coefficients of a Very High-rise Steel Artificial Reef
Hyun-Kyoung Shin ; Ho-Gyun Park ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 44~52
A modeling program was developed in Part I which represents the 3-D geometry, produces bill of material, automatically draws drawings and produces input data for structural analysis of Very High-rise Steel Artificial Reefs(VEHSAR). Model tests were carried out to measure drag forces acted on VEHSAR in the Ocean Engineering Wide Tank, the University of Ulsan and structural analyses were made to simulate structural behaviors of VEHSAR. The integrated package system is suggested to design VEHSAR with different geometries.
A Study on the Development of a Freeform Surface Cutting Machine
H. Shin ; H.L. Lee ; K.W. Park ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 53~61
A cutting machine for freeform hull surfaces of ship models is developed and a servo system is employed for tool path control. The servo system consists of BLDC(Blushless DC) motor, control driver and host controller. Also PI controller is applied for precision processing. GUI(Graphic User Interface) was realized by visual c++ for the convenience of users. Free form surfaces are formed by the cutting machine developed in the Ocean Engineering Wide Tank of the University of Ulsan.
An Experimental Study of Characteristics of Plate Deformation by Heating Process
Chang-Doo Jang ; Dae-Eun Ko ; Byeong-Il Kim ; Jeong-Ung Park ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 62~70
As the ship hull is a compound-curved structure, plate bending process is indispensible. The process includes press bending process for forming major 1st curvature and heating process for forming the rest curvature. Especially the heating process that is above 50 percents of entire bending work is carried out exclusively by skillful workers. Many researches have been made to automate the heating process but most of these are about line heating process and researches for triangle heating process are rare. This study is a fundamental study to develop a efficient analysis method for triangle heating and focused on clarifying the deformation characteristics of plate by triangle heating. In this paper, we carried out heating experiments and analysed the deformation characteristics of plate to explain the deformation characteristics of plates rationally by showing the phase transformed high temperature region. Also we investigated the heating effect on the hull material properties by mechanical tests.
Ship Hull Modeling by CAD/CAM System
Tae-Wan Kim ; Jae-Hwan Lee ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 71~78
In ship building industry, CNC and CAM are mostly applied to NC cutting and manufacturing of propeller and prototype ship model. Herein, prototype ship model is producted by CAD/CAM process. Hull form data is obtained from the ship drawing and used for 3D modeling by CAD software Pro/Engineer. CAD data is transferred into CAM s/w SPEEDplus to perform CNC process and the prototype small ship model is manufactured by CNC machine. To solve data transfer among different systems. IGES and STEP neutral formats are currently used. Herein IGES format is adopted for data transfer between CAD/CAM softwares.
Ship block assembly modeling based on the graph theory
Hag-Jong Jo ; Kyu-Yeul Lee ;
Journal of the Society of Naval Architects of Korea, volume 38, issue 2, 2001, Pages 79~86
This study shows an attempt to generate an assembly sequence and its model for a ship block assembly using the graph theory and graph algorithms. To generate the ship block assembly, we propose four levels of the ship block assembly model such as "geometry mode1", "relational model", "sequential mode1", and "hierarchical model". To obtain the relational model, we used surface and surface intersection algorithm. The sequential model that represents a possible assembly sequence is made by using several graph algorithms from the relational model. The hierarchical model will be constructed from the sequential model in order to represent the block assembly tree and so forth. The purpose of the hierarchical model is to define an assembly tree and to generate the Bill Of Material(BOM). Lastly, the validity of the method proposed in this study is examined with application to ship block assembly models of a single type and double type according to four models mentioned above.