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
A Study on the Control System of Dynamic Vibration Absorber for Ship Superstructure
S.S. Kim ; S.Y. Han ; J.K. Eom ; M.H. Hyun ; J.H. Kim ; M.H. Kim ; D.K. Lee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 1~18
This paper deals with the vibration absorbers of gravitational and centrifugal pendulum types for vibration controls of ship's substructures such as radarmasts, bridgewings and funnels. The mathematical model of such a vibrating system with an absorber is described as a 2 degree of freedom system and an efficient formulation for optimum design of the absorber is presented. For investigation applicability of the two types of the absorbers to a structure system, numerical calculations and experiments hove been performed with variation of mass ratios for each type. According to the results of investigations, the vibration absorber of gravitational type proved to be more useful and efficient than one of centrifugal pendulum type in a view point of mass ratio.
A Study for Hull Form Design of the SWATH Ship
C.T. Song ; C.W. Park ; B.H. Heo ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 19~28
This paper presents hull form design details and performance characteristics of the SWATH ship 'SEON JIN' built as an underwater test support ship. The hull form is developed systematically varing sets of 11 form parameters which define a unique hull under waterline. Using this geometry variation scheme we have generated a number of alternatives and selected the final hull which fulfills the design objectives and matches the design constraints. After selecting the final hull form we have investigated performances thoroughly through model tests, and confirmed through sea trials that the performance goals be achieved.
Variation of the Hull Form using SAC and NURBS Curve
Hyun-Cheol Kim ; Soo-Young Kim ; Dang Ahn ; Mun-Keun Ha ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 29~36
This paper presents a variation method of the parent ship using sectional area curve & the definition of NURBS curve. That is, global variation of the hull form is made systematically by the geometrical property of sectional area curve, and Local variation of the hull form is executed by the definition of NURBS curve. Then the designer may determine New hull form considering New section area curve, design condition, etc.
Evaluation of Foil Strength by Full Scale Strain Measurement
I.H. Choe ; K.Y. Chung ; O.H. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 37~43
The procedure and the results of the full scale strain measurement of the long-range high-speed foil catamaran are described. The wave induced stresses at the center struts of the foils were measured during the sea trials in order to evaluate the hydrodynamic force acting on the foils and to verify the structural safety of the foil structures. From the statistical properties of the measured response of the stress, the most probable maximum values of the lift force and the stresses at the foils in service life of the ship are predicted and compared with the design parameters of the foils which were applied in the design of the subject ship. The available prediction processes of the measured stress are studied and the results of the applied processes are compared with each other.
A Block Division CAPP System Supported by Expert System
Jae-Won Lee ; In-Sik Hwang ; Yong-Jae Lee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 44~50
We describe here the research work concerning the development of the CAPP(computer aided process planning) system, named BLOCK. designed to support block division of ship. The system consists of the expert system part generating block division lines, and their evaluation and editing one. As a reasoning approach of expert system, the case-based reasoning is used. The division lines can be graphically edited and the satisfaction measure of block division can be checked up in the evaluation stage with separate window. The expert system is developed by using NEXPERT Object development tool in the workstation. Currently the target ship is VLCC.
A Computational Study on Vortex Shedding around a Hydrofoil
Wu-Joan Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 51~61
A numerical method was developed to solve the Navies-Stokes equations for unsteady laminar flow around a hydrofoil. The present method used the finite-difference scheme in the collocated grid system and the pressure-Poisson method was employed to obtain divergence-free velocity field each time step. The numerical method was applied at first to laminar flow around a circular cylinder to confirm capability of the code. In the next, calculations were carried out for a hydrofoil in an unbounded fluid at the Reynolds number of
in order to investigate unsteady phenomena with vortex shedding. The calculate results showed reasonable features about laminar vortex shedding around a streamlined body.
A Numerical Analysis on the solution of Poisson Equation by Direct Method
Y.S. Shin ; K.P. Rhee ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 62~71
In the numerical analysis of incompressible unsteady Navier-stokes equation, large time is required for solving the pressure Poisson equation of the elliptic type at each time step. In this paper, a numerical analysis by the direct method is carried out to solve the pressure Poisson equation and the computing time is analyzed as mesh size increases. The pressure Poisson equation can be transformed to the boundary value problem by the Green theorem. The computing time for the convolution type of the domain integral can be reduced by using F.F.T. and the computing time in the direct method depends entirely on obtaining the solution of the boundary value problem. The numerical analysis on the known solutions is carried out and compared for the verification of the direct method. And the numerical analysis on the body boundary and domain decomposition problem are carried out with the computing time less than O(
) in the (n.n) mesh.
A Numerical Calculation of Viscous Flow around a Hydrofoil Advancing beneath the Free Surface
J.J. Park ; S.M. Jeong ; Y.G. Lee ; S.H. Lee ; S.W. Hong ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 72~82
In the present paper, flow characteristics and free surface waves generated by a submerged hydrofoil advancing with an uniform speed are calculated. Using a numerical method based on a MAC(Marker And Cell) method, the Navier-Stokes and the continuity equations are solved to simulate flow fields around the hydrofoil. Computations are carried out in a rectangular grid system in which grids are concentrated near the foil and the free surface to improve numerical accuracies. Viscous flow phenomenas including pressure distributions are computed. Moreover, the influences of submerged depths upon the generated wave profiles and the wave breaking phenomena are also investigated. Experiments are performed at the towing tank of Inha University to measure free surface wave elevations due to the advancing hydrofoil. The computational results are compared with the present and the other available experimental data to show the accuracy of the numerical method developed.
A Simple Formula for Ultimate Strength Prediction of Hull Girders
J.K. Paik ; A.E. Mansour ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 83~97
The aim of this study is to derive a simple formula for predicting ultimate strength of hull girders under vertical bending moment. The existing formulas have been reviewed and classified into analytical approach, empirical approach and linear approximate approach. It is known that the ship hull will reach the ultimate limit state if both collapse of the compression flange and yielding of the tension flange occur. Side shells in the vicinity of the compression and tension flanges will often fail also, but the material around the final neutral axis will remain in the elastic state. Based on this observation, a credible distribution of longitudinal stresses around the hull section at the overall collapse state is assumed, and an explicit analytical formula is derived. The accuracy of the formula has been verified by a comparison of the experimental and the numerical results.
Vibration Analysis of Mindlin-Plate Structures having Attachments by the Receptance Method
S.Y. Han ; J.H. Chung ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 98~106
In ship and offshore structures, there exist many local structural systems which may be regarded as a combined structural systems composed of thick plates or double wall panels and attachments reducible to damped spring-mass systems. For vibration analysis of such a combined system an analytical method based on the receptance method is presented in this paper. The free vibrational characteristics and forced vibration responses of the combined system can be calculated by synthesis of receptances of the panel and attachments. To calculate receptances of the panel, it may be regarded as a Mindlin plate for consideration of effects of shear deformation and rotary inertia and the assumed mode-Lagrange's equation method is applied using Timoshenko beam function or polynomials having properties of Timoshenko beam function as trial functions. Through some numerical calculations, accuracy and efficiency of the presented method are shown.
Development of Longitudinal Ultimate and Residual Strength Estimation System for Hull Girder Structure
J.H. Ham ; U.N. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 107~115
A simple estimation system of ultimate and residual strength for ship structures is developed on the Open-Window system of SUN4 engineering workstation. System development consists of three stages. Firstly, various ultimate longitudinal strength estimation methods are investigated and some rational estimation methods are adopted based on the parametric comparison of various hulls or box girders. Secondly, these selected and newly formulated methods are linked with elastic & perfectly plastic section modulus calculation procedure. Therefore, the longitudinal hull girder strength can be calculated in the intact and damaged conditions due to the grounding or collision of hull structure. Finally, an exclusive system is developed such that whole procedures are proceeded under the window management system using mouse button and elastic and perfect plastic stress conditions. Also longitudinal members are plotted automatically under three dimensional graphic circumstances. These established program is tested for various actual ships, and some examples are illustrated.
Vibration Analysis of Quadrangular Plate having Attachments by the Assumed Mode Method
S.Y. Han ; Y.C. Huh ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 116~125
In ship and of offshore structures, there exist many local panels of various shapes having many kinds of attachments reducible to damped spring-mass systems. For the vibration analysis of panels, analytical methods such as Rayleight-Ritz method or the assumed mode method can be efficiently applied. There have been many studies on the vibration analysis of rectangular panels using the analytical methods but relatively few for arbitrary shape panels. An efficient formulation based on the assumed mode method is presented for the vibration analysis of an arbitrary quadrangular plate having concentrated masses, supporting springs such as pillars and spring-mass systems. In the formulation, the natural coordinate system is used for the efficient treatment of an arbitrary quadrangular shape. Through some numerical calculations, accuracy and efficiency of the presented method are shown.
A Study on the Crack Initiation Life for Crankshaft of Mid-size Engine
Juh-H. Ham ; Myung-H. Hyun ; Su-H. Kim ;
Journal of the Society of Naval Architects of Korea, volume 32, issue 3, 1995, Pages 126~134
The crack initiation life evaluation which is the most commonly used approach in fatigue strength studies for the designers, is performed for the crankshaft of mid-size engine. In order to evaluate the fatigue strength, structural analysis model and applied loads on crankshaft are prepared based on the cyclic system. Using the response data of the finite element analysis, crack initiation life is predicted and plotted on crankshaft geometric model. In this analysis, general purpose programs such as PATRAN, NASTRAN and EMRC/NISA are actively utilized. Life distribution contour plots, which is not yet established as an active tool in actual design system of ship structure & components, are suggested and examples for active predicting procedure such as stress contour plotting in structure strength analysis, are illustrated. Additionally, several correlated equations for prediction of the crack initiation life are introduced and discussed to improve the fatigue strength prediction of crankshaft.