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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 30, Issue 4 - Nov 1993
Volume 30, Issue 3 - Aug 1993
Volume 30, Issue 2 - May 1993
Volume 30, Issue 1 - Feb 1993
Selecting the target year
The Development of Knowledge Based System for Main Engine Selection of Ships
Dong-Kon Lee ; Kyung-Ho Lee ; Kyu-Yeul Lee ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 1~7
This paper describes development of a knowledge-based system for main engine selection of ships using general purpose expert system development tool, Nexpert Object. Developed system consist of ship performance estimation module such as resistance and propulsion, data base for main engine, knowledge base for main engine selection in Nexpert Object and graphic user interface.
Failure Detection Filter for the Sensor and Actuator Failure in the Auto-Pilot System
Sang-Hyun Suh ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 8~16
Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dim in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.
A Study on Hull Form Design Techniques Based on Graphical User Interface
H. Shin ; K.W. Park ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 17~22
The intersection problem of three-dimensional free form surfaces can be solved by geometrical and numerical methods. Up to now, the subdivision technique, which is classified under the former, has been largely employed to find the cross section of ship hull form. In this paper, an algorithm is presented for intersecting ship hull form in high speed. The high speed calculation algorithm is based on simple numerical methods, such as the secant method, false position method and bisection method. The algorithm is directly applicable to depicting arbitrary ship cross sections, drawing ship lines and constructing the offset table.
Investigation on the Aerodynamic Performance of a Wells Turbine for Ocean Wave-Energy Absorption
Beom-Soo Hyun ; Jung-Chun Suh ; Pan-Mook Lee ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 23~30
This rape deals with the experimental and theoretical investigations on the aerodynamic performance of the Wells turbine. The two-dimensional cascade theory is used to estimate the thrust and torque of turbine, and finally to yield an efficiency of turbine. The turbine is assumed to rotate with a constant rotational speed in a sinusoidally varying unsteady flow field. Experimental approach is made in a wave simulator, producing a sinusoidally reciprocating air flow corresponding to the wave motion in an Oscillating Water Column(OWC) chamber. Performance data of turbine measured at various operating conditions are analyzed and compared to numerical results in order to understand the overall features of a Wells turbine.
Effect of a Gap of a 2-D Flap Rudder on the Lift
Chang-Gu Kang ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 31~38
Horn rudders or flap rudders with a gap between forward and after part are used for effective steering of a ship or a submerged body. It is necessary to analyze the effect of a gap since it affects the performance of rudders. In this paper, an equation to calculate the lift acting on a two-dimensional flap rudder in uniform flow is derived by using the thin hydrofoil theory and the analytic solution of viscous flow in a channel formed by two coaxial cylindrical walls to which a pressure gradient is applied.
Statistical Analysis of Random Ship Rolling Using Equivalent Linearization Method
Dong-Soo Kim ; Won-Kyoung Lee ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 39~45
In order to analyze the rolling motion of a ship in random beam waves we have used the equivalent linearization method. The quadratic nonlinear damping, the cubic and quintic nonlinear restoring moments were added to a single degree of freedom linear equation of roll motion. The irregular excitation moment was assumed to be the Gaussian white noise. The statistical characteristic of the response by the equivalent linearization method was compared with the simulation result.
Measurement Uncertainty Analysis for Fluctuating Hull Pressure
G.I. Choi ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 46~60
Accurate measurements of fluctuating pressure in the cavitation tunnel are necessary to predict vibration and noise intensities in full scale ship. In this paper, the results of an experimental study on fluctuating pressure induced by a cavitating propeller are presented and discussed. Extensive measurements at several propeller revolutions are made using the flat plate to understand controversial problems of the effects of propeller revolution in the cavitation tunnel. The analysis of the uncertainties in experimental measurements and results is used to estimate the errors in uniform flow.
A Numerical Study on the Prediction of Sloshing Impact Pressure
Y.H. Kim ; Y.J. Park ; H.R. Lee ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 61~73
In the present study, sloshing problem is analyzed by the application of Finite Difference Method. SOLA-SURF scheme is applied to the analysis of fluid motion considering free surface. Especially, the concept of impact buffer zone is introduced for the prediction of more realistic impact pressure on tank. Numerical computation is carried out for the typical three models, and the computed results show good agreement with experimental data. The computation is also performed for 300,000 tons VLCC as a real-ship application. From the present study, it is proved that this numerical technique is quite practical to the prediction of sloshing impact pressure.
Structural Safety Assessment of Independent Spherical LNG Tank(2nd report) - Fatigue Crack Propagation Analysis Based on the LBF Theory -
In-Sik Nho ; Yong-Yun Nam ; Ho-Sup Lee ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 74~82
The present paper deals with the structural safety assessment techniques for independent type B spherical LNG tank against fatique crack initiation and propagation, which contains fellowing 3 steps. 1) Prediction of long term distribution of wave induced stresses and fatique crack intiation life using cumulative damage theory which were described at the 1st report. 2) Surface crack propagation analysis to verify that initial defects cannot penetrate tank plate. 3) Passing-through fatigue crack propagation analysis was performed based on LBF(Leak Before Failure ) theory.
Structural Safety Assessment of Independent Spherical LNG Tank(3rd report) - Safety assessment of tank system against crygenic temperature -
Yong-Yun Nam ; In-Sik Nho ; Ho-Sup Lee ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 83~92
This paper describes structural safety assessment techniques against crygenic temperature to design MRV type B LNG tank system. The following items are detail with in detail. (1) Leakage estimation of LNG through the propagating clacks at tank plate was performed and design of the range of catch basin(2ndary barrier) was followed to ensure the safety of ship structures against leaked LNG. (2) Temperature distribution analysis for cargo hold and skirt system was carried out using the steady state heat transfer analysis model for spherical LNG tank system. (3) Thermal stress distribution of skirt and tank system was calculated, where very stiff thermal variation was shwn through item(2) analysis.
An Efficient Algorithm in Spectral Fatigue Analysis of Ship Structures
Jeung-Je Kim ; Bum-Sang Yoon ; Park-Dal-Chi Yang ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 93~101
This paper deals tilth an efficient algorithm in spectral fatigue analysis of ship structures. The concept of stress influence coefficients is suggested in order to obtain stress transfer functions efficiently which are the structural responses for unit load components. Strip method is applied to obtain the motion response and pressure distributions exerted on the hull. Since a number of the structural analysis should be performed for the various wave frequencies and heading angles in the spectral analysis, the algorithm developed in this study improves the efficiency of the analysis. Finally, the calculation example with application to this concept is shown in this paper.
A Study on The Evaluation of Fracture Strength for Large Sized Structures Based upon Their Fracturing Characteristics
Moon-Sik Han ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 102~111
One of the most important design procedures for large sized structures is the evaluation of fracture strength against fatigue and brittle fractures threatening to occur in their steel members. In this paper, the safety assessment based upon the knowledge about the fracturing characteristics of such ship structures was discussed, which can be estimated from such phenomena as fatigue crack propagation and brittle fractures, as obtained by employing fracture mechanics at the basic design stage. Model tests with a partial structure specimen of full size was carried out to authenticate a question as to whether or not the fracturing characteristics of such sophisticated structures could be estimated with precision from ordinary scale specimen tests, It was shown that the behviour of fatigue crack growth of large sized structures in this study could be predicted from the results of ordinary scale specimen test.
On The Development of Design Wave Loads in Classification Rules(I)
J.Y. Song ; Y.K. Chon ; T.B. Ha ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 112~126
In this paper, unified requirements of IACS on longitudinal strength of ships are investigated using nonlinear wave loads analyses under short term irregular waves. Also, analyses on IACS wave data were carried out for the purpose of presenting the guideline for future use. While keeping theoretical consistensy, the rule requirements for horizontal shear force, bending moment and torsional moment are newly proposed for the ships of large deck openings bases on the calculation results for 17 sample ships. The requirements for side shell hydrodynamic pressure are also presented. All the calculated results are compared with other Societies and present KR rules. These formula will be checked when corresponding requirements of structural scantling are determined.
Simplified Estimation of the Ultimate Strength of Ship Panels using Statistical Data of Actual Ships
Oi-H. Kim ; Juh-H. Ham ; Ul-N. Kim ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 127~135
The ultimate strength formulas of ship panels are suggested in a simple and suitable form. Firstly, these formulas are derived from a full description of the variables that govern plate strength by using statistical data of actual ships. Secondly, under the assumption of plate mid-edge collapse using the Von-Mises' yield criterion and the new buckling formula, a general equation for the ultimate strength estimation is also derived. The existing test data are compared with these new formulas and a good correlation is shown.
Thin-Walled Beam Model for Structural Analysis of SWATH
Sang-Gab Lee ; Yoon-Sup Ko ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 136~152
This study is intended to develop an accurate and efficient, analytical thin-walled beam model, and to analyze overall behavior of SWATH ship under repeated overloads. SWATH ship is idealized to a simple thin-walled beam of channel type. An analytical beam model is formulated by the stress component with geometrically(fully) nonlinear thin-walled beam and treated numerically by the Finite Element Method. An efficient cyclic plasticity model is also included, suitable for material nonlinear behavior under complex loading conditions. The local stress distribution can be very exactly represented and the material yielding propagation, easily traced. In addition, the local treatment of the effect of shear deformation improves the representation of deformation and shear stress distribution along the section contour. It is desirable to use the analytical thin-walled beam at initial design stage, and is needed to improve the practical thin-walled beam model advancing the current approach.
A Strength Analysis of the Hull Gilder among the Rough Sea according to Ship Types
Sa-Soo Kim ; Ku-Kyun Shin ; Sung-Wan Son ; Jae-Hong Kim ;
Journal of the Society of Naval Architects of Korea, volume 30, issue 4, 1993, Pages 153~168
The ship sailing among waves suffers from the various wave loads that comes from its motion throughout its life. In the rationally-based design, the dynamic structural analysis is carried out using dynamic wave loads provided from the results of the ship motion 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, relatively high wave compared to the height ship's depth is induced the large ship motion, so configuration of the ship section below waterline changes rapidly at each time. This re-sults in a non-linear problem. Considering above situation we have already introduced the non-linear dynamic strength analysis method for the hull girder(refer vol. 29. No.4 November, 1992, Journal of SNAK). In this paper, estimation of the hull girder strength for various ship types such as tankers, containers and log carriers is carried out based on the introduced non-linear method. We expect that the results will be used as useful basic data for the es-timation of dynamic strength of ships in the rough sea.