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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
Editor in Chief :
Volume & Issues
Volume 29, Issue 4 - Nov 1992
Volume 29, Issue 3 - Aug 1992
Volume 29, Issue 2 - May 1992
Volume 29, Issue 1 - Mar 1992
Selecting the target year
Bow-Hull Form Development of a Container Ship by Using Finite Difference Method
S.C. Shin ; U.C. Jeong ; Y.G. Lee ; K.J. Kang ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 1~6
The finite difference simulation method for ship waves is introduced for hull form improvement. Numerical simulations were performed for a series of modified hull forms and the simulated results were used for the determination of the better hull forms. A 4,400 TEU container carrier which was designed and experimented in towing tank was chosen for the purpose. The calculation results are compared with those of model test, of simplified Neumann-kelvin problems and of Rankine source method. In this study, it is shown that the combination of the computer simulation by our method with the experiment provides one of the most economical and reliable procedures of hull form improvement and that the degree of accuracy of this method is so high that it can cope with very practical design purposes.
Visualization of Calculated Flow Fields Using Methods of Computer Graphics
Soon-Hung Han ; Kyung-Ho Lee ; Kyu-Ock Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 7~17
Developments in the emerging field of Computational Fluid Dynamics(CFD), which is made possible by the supercomputer technologies, introduce a new problem of analysing the massive amount of output produced. This problem is common to fields of computational science and engineering. Scientific visualization is to solve this problem by applying advanced technologies of computer graphics. Methods of scientific visualization are studded to visualize calculated flow fields. Different methods of scientific visualization has been surveyed, analysed and compared to select one method, iso-surface. Methods of constructing iso-surfaces from a 3-D data set have been studied. A new algorithm for constructing iso-surfaces has been developed. The algorithm can be classified as one of surface tiling methods. To develope a portable visualization system the international standard PHIGS PLUS and its implementation on X-Window system, PEX, have been selected as the development environment. A prototype of visualization system has been developed. The developed visualization system has been tried to visualize several well-known flow fields.
User-Oriented Interactive Model for Conceptual Design of Ship
D.K. Lee ; K.H. Lee ; S.H. Han ; S.S. Lee ; K.Y. Lee ; S.C. Shin ; D.W. Shin ; J.C. Lee ; S.C. Kwon ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 18~26
This paper describes a design model for conceptual design of ship. Existing design models have some problems. For example, operating environment of batch versions can not reflect design procedure of real world truely and reliability of results are not high because means of performance estimation are based only on empirical formula. To improve these problems of existing design models, a new design model has been developed. The new model consists of interactive environment with databases of main engine and existing ship data. To develop user-oriented system, graphic user interface(GUI) is adapted.
Object-Oriented Graphical User Interface Model for Visualization of Ship Conceptual Design
Kyung-Ho Lee ; Soon-Hung Han ; Dong-Kon Lee ; Kyu-Yeul Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 27~35
By the help of computer graphics and rapid development of hardwares. GUI(Graphic User Interface) represented by WYSIWYG(What You See Is What You Get) changed user interface from liguistic model(e.g : command, etc.) to spatial model(e.g : pulldown menu, scroll bar, icon, itc.). This graphical user interface model for the ship conceptual design(MBASWIN) adopted event-driven programming technique and object-oriented concepts. Different from traditional design programs, MBASWIN is separate from the design program completely and controls all design modules. This enable a designer to accomplish a flexible designs.
Preliminary Hull Form Generation Using Fuzzy Model
Soo-Young Kim ; Yeon-Seung Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 36~44
To improve the B-spline form-parameter method being used in preliminary hull form generation, this research considers fuzzy modeling of the relationships among form-parameters based on the actual ship data analysis. Form-parameter values are determined through fuzzy inference. To verify the validity of the proposed fuzzy model the hull forms of actual ships are compared with hull forms generated by fuzzy model.
The Representation Methodology for the Ship Model based on Product Model
W.S. Kang ; S.W. Suh ; D.W. Shin ; K.O. Lee ; K.Y. Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 45~57
In this paper, the trends for the standardization of the product model was surveyed, and the product model can be used as concrete means to realize the communication of information between the CAD/CAM softwares, which are used for the design and manufacturing of the complex products such as ships. We have proposed the newly developed methodology for the representation and definition of the ship model on a basis of the product model. And also we have studied the product modeling technology for the aspect of an application, and the object-oriented system technology have been surveyed for the system implementation issues. We would like to verify the consistency and correctness of our proposed representation methodology by using the prototype application model, which is applied to design work of ship compartmentation model. For this purpose we have developed the "OO_COMDEF"(which means the Object-Oriented System for the Compartmentation Definition of ship) program that is applied to the compartmentation model which can be considered as a submodel of the general ship models. The results of research work have been proved that the representation methodology for the ship model based on the product model is an efficient and appropriate scheme for the ship model definitions. Consequently, this methodology can be proposed as a fundamental framework for the development of the shipbuilding CAD/CAM system.
Calculation of Wave Resistance for a Submerged Body by a Higher Order Panel Method
Chang-Gu Kang ; Se-Eun Kim ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 58~65
In this paper, wave resistance for a submerged body is calculated by a higher order panel method. The Neumann-Kelvin problem is solved by the source or normal dipole distribution method. The body surface is represented by a bicubic B-spline and the singularity strengths are approximated by a bilinear form. The results calculated by the higher order panel method are compared with those by the lowest order panel method developed by Hess & Smith. The convergence rate of the higher order panel method is much better than the lowest order panel method. But the wave resistance calculated by the higher order panel method still shows discrepancy with an analytic solution at low Froude number like that by the lowest order panel method.
Computation of Wave Resistance in the Water of Finite Depth Using a Panel Method
S.J. Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 66~74
A panel method in the spirit of Hess & Smith(1962), and also of Dawson(1977) was developed to compute the wave resistance of a submerged, or a surface piercing, body moving in the water of finite depth. As a boundary condition on the free surface what is called the Poisson equation is used, while Yasukawa(1989) chose the Dawson equation for which the double-body flow is regarded as the basic one. In order to satisfy the boundary condition on the bottom surface automatically, the sum of a Rankine source and its image with respect to the bottom surface is chosen as the Green function, and hence the singularity is distributed only on the body and on the free surface thereby decreasing the required number of panels dramatically, compared to that of Yasukawa, without the consequential loss of accuracy. Calculations were done for a submerged sphere and for the Wigley hull, and the results are compared with other existing analytical and numerical data.
On the Added Resistance of SWATH Ships in Waves
Ho-Hwan Chun ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 75~86
This paper reports theoretical and experimental investigation into the added resistance of SWATH ships in waves. It was revealed from the experimental investigations on various SWATH models that the resistance of the SWATH models in waves is considerably reduced over part of the speed range as the wave height increases. As a first step to Identify it, the first and second order wave forces have been investigated barred on a linearised 3-D diffraction theory together with simplified boundary conditions and same results are reported herein. Also, the speed performance of SWATH ships in rough seas is compared with those of equivalent monohulls as well as with those of advanced high speed marine vehicles.
A Study on Bow Hull Form and Icebreaking Capability of Icebreaking Vessels
K. Choi ; C.B. Son ; E.G. Paeng ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 87~97
Of various design factors affecting icebreaking capability of an icebreaker, the stem angle(i.e., angle between bow stem and ice sheet) is the most important one under continuous icebreaking operation. This study focuses on the relationship between the bow stem angle of an icebreaker and its icebreaking capability. Considering relatively high loading-rate conditions with typical advancing speed of 3 to 4 knots, the material properties and deformation characteristics of sea ice are regarded as entirely elastic and brittle. In this paper the interaction process of icebreaker with level ice is simplified as a beam of finite length supported by Winkler-type elastic foundation simulating water buoyancy. The wedge type ice beam is loaded by the vertical impact forces due to the inclined bow stem of icebreaking vessels. The numerical model provides locations of maximum bending moment where extreme tensile stress arises and also possible fracture occurs. The model can predict a characteristic length of broken ice sheet upon the given environmental and design parameters.
Wind-Tunnel Experiment for the Steady and Unsteady Torques of a Control Panel
M.S. Suh ; S. Kauh ; S.H. Kang ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 98~103
The dynamic and static torque characteristics of a three dimensional control panel installed behind a guide panel were investigated in a wind tunnel. The panel was tested for various wind speeds, angles of attack and positions of the panel. The effects of the rotational speed and the amplitude of the sinusoidal motion were also studied. The increasing rate of torque coefficients with the angular position of the panel is small when the panel remains in the wake region, but is linear when it reaches the external stream. In case of a sinusoidal motion of the pannel, a hysterisis appears in the dynamic torque. The hysterisis becomes strong as the wind speed and the angular speed of the panel increase. The unsteady torque is considered quasi-steady when the angular speed is less than 5.5rad/s, i.e. the reduced frequency is less than 0.035.
On the Hydrodynamic Forces acting on a Partially Submerged Bag
G.J. Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 104~113
The hydrodynamic problem is treated here when a pressurized bag is submerged partially into water and the end points of it oscillate. SES(Surface Effect Ship)has a bag filled with pressurized air at the stern in order to prevent the air leakage, and the pitch motion of SES is largely affected by the hydrodynamic force of the bag. The shape of a bag can be determined with the pressure difference between inside and outside. Once the hydrodynamic pressure is given, the shape of a bag can be obtained, however in order to calculate the hydrodynamic pressure we should know the shape change of the bag, and vice versa. Therefore the type of boundary condition on the surface of a bag is a moving boundary like a free surface boundary. In this paper, the formulation of this problem was done and linearized. The calculation scheme for the radiation problem of an oscillating bag is shown in comparison with the case that the bag is treated as rigid body. The hydrodynamic forces are calculated for various values of the pressure inside the bag and the submerged depth.
The Nonlinear Motions of Cylinders(I)
H.Y. Lee ; J.H. Hwang ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 114~131
In the present work, a two-dimensional boundary-value problem for a large amplitude motion is treated as an initial-value problem by satisfying the exact body-boundary and nonlinear free-surface boundary conditions. The present nonlinear numerical scheme is similar to that described by Vinje and Brevig(1981) who utilized the Cauchy's theorem and assumed the periodicity in the horizontal coordinate. In the present thesis, however, the periodicity in the horizontal coordinate is not assumed. Thus the present method can treat more realistic problems, which allow radiating waves to infinities. In the present method of solution, the original infinite fluid domain, is divided into two subdomains ; ie the inner and outer subdomains which are a local nonlinear subdomain and the truncated infinite linear subdomain, respectively. By imposing an appropriate matching condition, the computation is carried out only in the inner domain which includes the body. Here we adopt the nonlinear scheme of Vinje & Brevig only in the inner domain and respresent the solution in the truncated infinite subdomains by distributing the time-dependent Green function on the matching boundaries. The matching condition is that the velocity potential and stream function are required to be continuous across the matching boundary. In the computations we used, if necessary, a regriding algorithm on the free surface which could give converged stable solutions successfully even for the breaking waves. In harmonic oscillation problem, each harmonic component and time-mean force are obtained by the Fourier transform of the computed forces in the time domain. The numerical calculations are made for the following problems.
Forced harmonic large-amplitude oscillation(
Translation with a uniform speed(
) The computed results are compared with available experimental data and other analytical results.
Development of a Preswirl Stator-Propeller System for Improvement of Propulsion Efficiency : a Symmetric Stator Propulsion System
Jin-Tae Lee ; Moon-Chan Kim ; Jung-Chun Suh ; Soo-Hyung Kim ; Jin-Keun Choi ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 132~145
A series of design, theoretical analysis and model test procedures is presented for the development of an axisymmetric stator-propeller system. A preswirl stator is located in front of a propeller in order to improve the propulsion efficiency by cancellation of the slip stream rotational velocity due to the propeller. Model test results show that propulsion efficiency gain due to the symmetric stator-propeller system is about 3% compared to the single propeller. This efficiency gain would increase for full scale application since the pressure drag coefficient of the stator would decrease due to increasement of turbulent intensity behind the hull wake and increasement of Reynolds number.
The Development of Analysis Techniques of Extreme Tensions in a Snapping Cable - Parameter Studies -
H. Shin ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 146~151
In this paper, extreme tensions in a snapping cable are studied and systematic parameter studies are made in the selected cable using the clipping-off model. The anticipation of incipient clipping frequencies of a cable are of use in giving an indication of the behavior of cables for marine applications in which large dynamic tension build-up in rough seas may cause the total tension to become negative.
A Study on the Dynamic Strength Analysis of the Hull Girder Among Waves Considering Non-Linear Hydrodynamic forces
Ku-Kyun Shin ; Sa-Soo Kim ; Sung-Wan Son ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 152~172
The ship sailing among waves are suffered the various wave loads that comes from its motion throughout its life. Because there are dynamic, the analysis of ship structure must be considered as the dynamic problem precisely. In the rationally-based design, the dynamic structural analysis is carried out using dynamic wave loads provided from the results of the ship mouton calculation as the rigid body. This method is based on the linear theory assumed low wave height and small amplitude of motion. But at the rough sea condition, high wave height, relatively ship's depth, is induced the large ship motion, so the ship section configulation below water line is rapidly changed at each time. This results in non-linear problem. Considering above situation in this paper, the strength analysis method is introduced for the hull glider among waves considering non-linear hydrodynamic forces. This paper considers that the overall or primary level of the ship structural dynamic loading and dynamic response provided from the non-linear wave forces, and bottom and bow flare impact forces estimated by momentum slamming theory, in which the ship is idealized as a hollow thin-walled box beam using thin-walled beam theory and the finite element method. This method is applied to 40,000 Ton Double-Skin Tanker and attention is paid to the influence of the response of ship speed, wave length and wave height compared with linear strip theory.
Limit State Design of Ship Structures Based on Reliability Analysis
Joo-Sung Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 173~178
This paper is in principle concerned with the reliability analysis and its based design of midship section against the ultimate bonding strength. Bulk carriers and oil tankers over 100m length are considered for this study. Target reliability indices are derived with the results of reliability analysis of the present ship models. Reliability-based structural design code formats are proposed for use in design of midship section of bulk carriers and oil tankers. The proposed design formats have been success fully applied to re-design of midship section of the present ship types and show the reasonable results. It has been found that the proposed code formats in this paper are useful for the re-deign of midship section of such ship types.
Constitutive Model for Plastic Damage of Ductile Materials
I.S. Nho ; S.J. Yim ; J.G. Shin ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 179~192
An elasto-plastic-damage constitutive model for ductile materials was derived under the framework of thermodynamic approach of contimuum damage mechanics(CDM) in which internal irreversible thermodynamic change of micro-structure of materials such as plastic deformation and damage evolution were considered as thermodynamic state variables. New constitutive model can predict not only the elasto-plastic behaviors but also the sequential degradation process of ductile materials more rationally.
Stress Analysis of the Corner Part of Ship Structures Using the New Equivalent Curved Beam Theory
Chang-Doo Jang ; Seung-Soo Na ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 193~201
A new equivalent curved beam theory is developed for the analysis of the corner part of ship structures, in which effects of distributed loads and asymmetricity with two or three connected parts are considered. Equivalent loads are obtained from equilibrium conditions between the distributed loads and the member forces and moments at the ends of curved beam. And an equivalent curved beam for the asymmetric structure is obtained by superposing the equivalent symmetric parts which have equivalent stiffness. From the sample calculation, it is found that the results of the new equivalent curved beam theory are well agreed with those of finite element method using membrane elements with little computing time and sufficient accuracy.
On the Development of the Generalized Slope Deflection Method for the Analysis and Design of Ship Structures
Chang-Doo Jang ; Seung-Soo Na ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 202~213
For the analysis and design of ship structures the generalized slope deflection method(GSDM) taking account of axial elongation effect as well as the bending and shearing deformation is developed. Using the span point concept, the existing slope deflection method is easy to transform the variable section to the equivalent uniform one under the bending moment and the shear force, but it is difficult to analyze the web frame with inclined members because the axial deformation effect is not considered. In the present method, the equilibrium conditions including all force components(i.e. axial force, shear force, bending moment) are formulated at the both ends of the variable section beam, such that the usual space frame stiffness equation which can be solved easily by the matrix method is derived. The accuracy and applicability of the present method is demonstrated by analyzing the ship web frame structures.
Experimental Study on Fatigue Characteristics of the Single Spot Welded Joint
Chang-Min Suh ; Sung-Soo Kang ; Nam-Seong Hwang ; Yong-Ich Cho ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 214~226
In this paper, the characteristics of fatigue crack growth in the spot welded joint of the same kinds of specimens(
) and different kinds of specimens(
) which consist of dual phase high strength steel(HS) and monogalvanized steel(GA) were examined with static tension tests and axial tension fatigue tests. Some of the important results are as follows : 1. The divergence of tensile strengths among the same and different kinds of spot welds under the same conditions is comparatively low regardless of the difference of stiffness. 2. At the low load bevel and long life legion, the fatigue crack is initiated near the nugget. However, in the high load level and short life region, it occurs a tittle far from the nugget. 3. It has shown a linear relation between maximum stress Intensity factor, Kmax and fatigue life,
among each of the spot welds and has gathered in a narrow band on the log-log graph paper.
where H and P are a material constant.
A Geometrically Nonlinear Analysis for the Eccentric Degenerated Beam Element Considering Large Displacements and Large Rotations
Jae-Wook Lee ; Young-Tae Yang ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 227~233
To study the large displacement and large rotation problems, geometrically nonlinear formulation of eccentric degenerated beam element has been developed, where the restrictions of infinitesimal rotation increments are removed and the incremental equations are derived using the Taylor series expansion of the displacement function at time t+dt. The geometrically nonlinear analyses are carried out for the cases of cantilever, square frame, shallow arch and 45-degree bend beam and all of them are compared with each of the other results published. The element developed in the present research can be efficiently utilized for analysis of the nonlinear behaviours of structures when displacements and rotations are large.
Estimation of Fatigue Crack Initiation Life Distribution by Multi-notched Specimen
S.W. Kang ; D.S. Uom ; J.H. Lee ;
Journal of the Society of Naval Architects of Korea, volume 29, issue 4, 1992, Pages 234~243
Fatigue crack initiation life has a wide scatter and this makes the fatigue design of structural members difficult. In order to make the fatigue life distribution clear, it is required to prepare a large number of specimens and repeat the fatigue tests under the same loading condition. Such fatigue tests usually take much time and cost. In this study, a fatigue testing method using a multi-notched test specimen for the purpose of estimating the distribution function of fatigue crack initiation life by small number of fatigue tests is used. The purpose of this study is to verify the above fatigue testing method of a multi-notched specimen by using Bayesian reliability analysis, Least square method and Skewness method for the determination of unknown Weibull parameters. The multi-notched specimen is a specimen in which several tens of statistically identical notches are prepared.