Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Society of Naval Architects of Korea
Journal Basic Information
Journal DOI :
The Society of Naval Architects of Korea
Editor in Chief :
Volume & Issues
Volume 32, Issue 4 - Nov 1995
Volume 32, Issue 3 - Aug 1995
Volume 32, Issue 2 - May 1995
Volume 32, Issue 1 - Feb 1995
Selecting the target year
Determination of the hull form factors about a high speed coastal fishing boat using Fuzzy modeling
Soo-Young Kim ; Hyun-Cheol Kim ; Kil-Hong Lee ; Ju-Nam Kim ; Young-Dae Son ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 1~8
This paper is presented determination of the hull form factors about a high speed coastal fishing boat using Fuzzy modeling. That is, the estimation curves of total resistance & EHP(Efficiency Horse Power) are induced by Fuzzy modeling algorithm from data of accumulated hull form factors and are compared with the results of model test. Also, the estimation curves of total resistance & EHP are utilized efficiently in determination the hull form factors about a high speed coastal fishing boat.
A Framework for the Geometric Modeler with Open Architecture
S.H. Han ; G.H. Choi ; S.H. Myung ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 9~18
The use of CAD/CAM systems is growing fast in the shipbuilding industry. To develope a geometric modeler, the existing CAD/CAM systems have been analysed. Because existing systems have closed architectures, it is not easy to investigate the internal structures. However, new trends in the software engineering, open architectured systems, pose some possibility to develope the geometric modeler. Several geometric modelers are analysed to extract component functions and modules. ACIS of the Spatial Technology, AIS of the CAM-I consortium, the STEP part for the geometry and topology, CAD*I of the ESPRIT project, and domestic modelers are investigated. Based on this analysis, a reference model which shows the framework of the modeler is proposed. With the data structure supporting non-manifold topologies, the reference model can be used to encourage a cooperative development program.
Prediction of Maneuverability of a Ship in the Initial Design Stage
S.K. Lee ; S.J. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 19~26
The assessment of maneuverability of a ship is very important from the view point of safety of human beings and of pollution of ocean. And, it is quite natural that every ship yard wants to have some tools with which they can build a ship with good maneuverability. But, maneuvarability of a ship is very subtle problem, and to calculate the exact maneuvering motion, lots of captive model tests must be carried out. Futhermore, in the initial design stage we can not make the scale model, because the lines of a ship is not fixed. In this paper, some approximate method to calculate the maneuvering motion of a ship, with the principal dimensions of hull, and propeller, rudder characteristics only, is studied. And, proposed approximate method is used to calculate the turning and zig-zag maneuver of several ships. The results of those calculations and the usability of the method are discussed.
On a Performance Index of Automatic Steering System of Ships
Kyoung-Ho Sohn ; Gyoung-Woo Lee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 27~37
A performance index is very important and indispensable to the evaluation of automatic steering system of ships in open sea from the viewpoint of energy saving. In this paper, we derive the performance index of automatic steering system from the concept of energy loss of propulsive power. The index is found to consist of three terms, energy loss due to elongation of sailing distance, energy loss due to steering, and energy loss due to yawing motion. We also provide two kinds of calculation method on the performance index ; frequency response analysis and digital simulation. The numerical calculations are carried out for an ore carrier and a fishing boat by both methods. The frequency response analysis is found to be useful if the system is linear and the disturbance on ship is not large. If the system is nonlinear or the disturbance is excessive, the method of digital simulation has to be applied for the accurate evaluation of the performance index. Further investigations into the effects of nonlinear elements such as weather adjuster, power unit etc. on the performance index, will be dealt with in another paper.
Effective Simulation Technology for Near Shore Current Flow
B.S. Yoon ; J.H. Rho ; M. Fujino ; T. Hamada ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 38~47
The three-dimensional multi-layer computer simulation technology for tidal current developed in the previous study is updated to a new version. many improvements are achieved by following changes : (1) No-reflection condition is adopted instead of no-gradient condition as an open boundary condition. (2) Time marching algorithm is changed so that velocity and pressure(surface movement) might be salved in turn at different time step (3) Convection term in equation of motion is estimated by upwind differencing scheme instead of central differencing. The stability is improved considerably and the steady state is achieved within 2 tidal periods which is about 3 times shorter than that of the old version. Moreover, fluctuations in time disappeared by introducing the new time marching technique. An application to the real near shore area(near Inchon harbor) is performed by the new version. Simulated results are compared with those by the simulation total developed in the University of Tokyo. Validity and effectiveness of the two simulation technologies are chocked through the comparative research works.
A Design Experience of Propeller Open Water Testing Dynamometer
J.S. Kim ; M. Song ; H. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 48~54
A new propeller open water testing device is developed and tested in a tow tank. The devised dynamometer consists of a torque measuring part, a thrust measuring part and a driving motor with an RPM counter. Torque is designed to be measured directly from the torsion of the structure holding the motor by using strain gauges and, consequently, conventional slip ring is removed. Also, in order to make the device fit in relatively small model ships, the weight and the size of the whole integrated structure are reduced in various ways. The developed tester is proved to be easily utilized in small circulating water channel experiments and is believed to have provided us with essential information for future design of various types of conventional or object oriented force measuring device.
Analysis of End-Plated Propellers by Panel Method
C.S. Lee ; I.S. Moon ; Y.G. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 55~63
This paper describes the procedure to analyze the performance of the end-plated propeller(EPP) by a boundary integral method. The screw blade(SB) and end-plate(EP) are represented by a set of quadrilateral panels, where the source and normal dipole of uniform strength are distributed. The perturbation velocity potential, being the only unknown via the potential-based formulation, is determined by satisfying the flow tangency condition on the blade and the end-plate at the same time. The Kutta condition is satisfied through an iterative process by requiring the null pressure jump across the upper and lower sides of the trailing edges of both the SH and the EP. Sample calculations indicate that the EP increases the loading near the tip of the SB while spreading the trailing vortices along the trailing edge of the EP, thus avoiding the strong tip-vortex formation. Predicted performance of the EPP shows good correlations with the experimental results. The method is therefore considered applicable in designing and analyzing the EPP which may be an alternative for energy-saving propulsive devices.
Design Sensitivity Analysis and Optimal Design to Control Forced Harmonic Vibration of Structure
J.H. Lee ; K.H. Lee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 64~72
Sizing design sensitivity analysis of structures subjected to the harmonic vibration is performed using adjoint variable method. Constraint is the stress and sizing design variables are thickness, bending moment of inertia, and cross-sectional area of structures. Accurate sensitivities are computed and plotted sensitivity can be used as a design guidance tool. The accuracy of sensitivities is verified by the finite difference values. Also, optimal design of three-bar structure is performed using the computed sensitivity and feasible direction method while satisfying constraints and obtaining the minimum weight.
Structural Damage and Residual Strength of Ships in Grounding with a Forward Speed
J.K. Paik ; T.K. Lee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 73~86
In this paper, the mechanics of ships in grounding with a forward speed is analyzed. A raking damage estimate model in grounding of ships is proposed. The accuracy and applicability of the model are verified by a comparison of experimental results. The progressive collapse analysis of damaged gull sections under vertical bending moments is described by using the ALPS/ISUM computer code. The procedure is applied to grounding simulation of a double hull tanker with a transverseless system.
Buckling Analysis of Sandwich Plate with Thin Faces
H.K. Yang ; J.W. Lee ; Y.H. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 87~96
This study is concerned with the overall buckling analysis of sandwich plates under biaxial loads by applying the Rayleigh-Ritz method, which are considered to buckle simultaneously in overall from of core and thin faces together. In order to study the effects of boundary conditions on the buckling behaviors, the simply supported, flexed and it's combined boundary conditions are considered as well as the effects of material characteristics of core and thin faces of sandwich plates on the buckling behaviors.
On the Dissipation Energy of a Tapered Box Column
J.M. Choung ; J.W. Lee ; S.J. Hong ; Y.H. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 97~104
A study on the structural dissipation energy and crushing strong is presented for the axially compressed straight square box column and off-axially compressed tapered box column. A new formula on the energy dissipation and crushing strength of the tapered box column is proposed, where the tapered box column is replaced by the equivalent straight square box column. It is seen that the theoretical solutions agree well with experimental results.
A Study to Develop an Active Control System of Ship Vibration Using a Mechanical Actuator
D.S. Cho ; S.M. Lee ; K.Y. Chung ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 105~113
A mechanical actuator to generate adjustable force ants its active control algorithm to minimize ship structural vibration are developed. The algorithms comprise initial algorithm which determines optimal phase and force magnitude of the actuator using the variation of vibration response according to the phase difference between the main engine and the actuator, and regulating algorithm which performs continuous optimal control to track the change of the engine speed. This control system can be applied without any prior identification for the dynamic characteristics of the controlled structure. In the control experiments for the deckhouse structural vibration of a 300,000 DWT crude oil carrier and a 2,270 TEU container carrier, the developed system showed good performance to reduce the vibration levels to
of the uncontrolled levels.
Numerical Simulation of Stress Waves in Plates with Material Interfaces
Kyung-Su Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 114~122
In this paper a computational method is presented to solve the plane problem of wave propagation in linear-elastic plate with zones of different materials. An existing numerical scheme of bicharacteristics for rectangular plate is extended to plates with curvilinear boundaries. In order to show the validity of the employed concept, it is necessary to examine the numerical results whether they reproduce the well-known physical phenomena of stress waves. It seems also desirable to make a comparison between the numerical results and appropriate experimental results for plates with curvilinear boundaries. Also studied are the focusing phenomena induced by reflection and refraction at curved outer boundaries and material interfaces.
Steady Drift Forces on Very Large Offshore Structures Supported by Multiple Floating Bodies in Waves(I)
H.J. Jo ; J.S. Goo ; S.Y. Hong ; C.H. Lee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 123~135
A numerical procedure is described for predicting steady drift forces an multiple three-dimensional bodies of arbitrary shape freely floating in waves. The developed numerical approach is based on combination of a three-dimensional source distribution method, wave interaction theory art the far-field method using momentum theory. Numerical results are compared with the experimental or numerical ones, which are obtained in the literature, of steady drift forces on 33(3 by 11) floating composite vertical cylinders in waves. The results of comparison confirmed the validity of the proposed approach. Finally, the interaction effects are examined in the case of an array of 40(4 by 10) freely floating rectangular bodies in shallow water.
Determination and Optimization of welding condition using Fuzzy Expert System for MAG-Welding
J.Y. Park ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 4, 1995, Pages 136~141
Determination and optimization of proper welding condition are very important tasks to be directly related to weld quality and productivity. On this research the relationship between welding parameters and results is investigated systematically. Theoretical method, statistical analysis of experimental data and analysis of empirical knowledge are applied for this work. These results are represented by empirical equations, fuzzy rules and artificial intelligent knowledge forms in the knowledge base. The approximate reasoning of fuzzy expert system and the information in the knowledge base are used for recommendation of suitable welding condition, and optimization of welding parameter which is based on the evaluation of welding results by user.