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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 35, Issue 4 - Nov 1998
Volume 35, Issue 3 - Aug 1998
Volume 35, Issue 2 - May 1998
Volume 35, Issue 1 - Feb 1998
Selecting the target year
Hull Form Development of the Medium Size High Speed Fishery Patrol Ship
Kwi-Joo Lee ; Kwang-Il Lee ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 1~7
Hull form development of the medium size high speed fishery patrol ship was carried out in the CWC at Chosun university. Same size of 15 knots class fishery patrol ship was selected as a parent form(Model number : CU-015), and modified fore and after body hull form under the slightly lengthened lo be suitable for the operation at 20 knots. To minimize the breaking wave in the vicinity of fore body at high speed zone, high bulb and sharp entrance angle were adapted. Meanwhile, to enlarge the engine room space keeping high resistance and sea-keeping Performance, U-type stern hull form was developed. Although the hull form was highly constrained in being limited to modification of a parent hull form significant wave resistance improvement was made.
Nonlinear Flow Characteristics of Two-Dimensional Hydrofoils moving below the Free surface
Il-Ryong Park ; Ho-Hwan Chun ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 8~19
Nonlinear flow characteristics of a hydrofoil running under the free surface are investigated based on potential flow theory using singularity distribution techniques. Following Hess & Smith's method, sources and vortices are distributed on the surface of the foil and Rankine sources are distributed at a distance above the undisturbed free surface to solve the nonlinear free surface waves(so called Raised Panel Method). Using the linearized Neumann-Kelvin solution, the conversed solutions which rigidly satisfy the nonlinear free surface condition is obtained through an iterative technique. It is validated that the nonlinear solutions are compared with Duncan's experimental results(NACA 0012,
), showing good correlations with each other. At a very shallow submergence and a very high speed the converged solutions are obtained. As the speed increases higher, it is shown that the difference between the nonlinear and linear solutions are trivial. Finally, the effects of the camber and thickness on the nonlinear flow characteristics of the foil are investigated.
The Combined Method of Structure Selection and Parameter Identification of Equations of Motion to Analyze the Model Tests of a Submerged Body
C.K. Kim ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 20~28
To accurately predict the motion of a submergible, the nonlinear structure of dynamic model should be selected and corresponding parameters should be estimated using model test. Providing the model structure, only the values of parameters are unknown and the estimation can thus be formulated as a standard least square problem. Unfortunately, the nonlinear model structure of submersibles is rarely known a prior and method of model structure determination from measurement data of model test should be developed and included as a vital part of the estimation procedure. In this study, the well-known linear least square algorithm for the analysis of model tests and a way to measure the goodness are reviewed, and the identification algorithm based on an orthogonal decomposition method of Gram-Schmidt is extended to combine structure selection and maneuvering coefficients estimation in a very simple and efficient manner. Finally, the efficiency of this algorithm is verified by using simulation and applying to the analysis of model test of a submerged body. As a result, it was verified that this combined method might be very erective in selecting the structure of dynamic model estimating the maneuvering coefficients from measurement fiat of model test.
Parameter Identifications of Roll Maneuvering Coefficients Based on Sea Trial Data
C.K. Kim ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 29~37
Linear equations of motion for submersibles are one of the rest important design parameters, which are used as a governing equation for the shape design and the controller design. But, the estimated maneuvering coefficients in equations of motion by using empirical formulae, theoretical calculations or model tests might have some errors. Therefore the maneuvering coefficients should be verified from sea trial test. In this study, parallel extended Kalman filter method, Nelder & Mead Simplex method and genetic algorithm were applied to the parameter identification of roll maneuvering coefficients based on sea trial data. As a result, it was verified that Nelder & Mead Simplex method gave the most satisfactory results for the mathmatical models and the sea trial data used in this study.
An Experimental and Numerical Study on the Characteristics of Pontoon Type Breakwater Fixed Near Free Surface in Regular Wave
M. Song ; D.Y. Kim ; H.Y. Lee ; I.H. Cho ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 38~50
In order to understand the characteristics of floating breakwaters we planned series of experimental and numerical investigations and completed the first stage which is the experiment with fred pontoons near the free surface. As controlling parameters the draft and breadth of pontoon were varied and the wave frequency and steepness were also varied. Wave transmission and forces exiled on the breakwater were experimentally investigated and compared with the results computed based on linear potential theory. Discussions made are on the effect of draft and wave length on the wave transmission and force in fixed pontoon case. The predicted and measured results show quantitatively good agreement both in forces and transmission coefficient. The effect of separation distance between two pontoons on the wave transmission and force in array case is also examined.
CAD/CAM System for 5-Axis Machining of Marine Propeller
Jae-Woong Youn ; Jong-Hwan Park ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 51~62
In this paper, a CAD/CAM system for 5-axis machining of model propeller is introduced. This system has been developed under the environment of personal computer and Windows NT. In order to enhance the productivity, existing text-based design S/W was integrated into this graphic-based system. Non-Uniform Rational B-Spline method is used to represent the sculptured surface of propeller blades and hub using point data, and surface blending between blade and hub is realized in this system. For 5-axis machining of sculptured surface, tool/work collision and interference are checked and inverse kinematic analysis is performed to make NC data. In addition, tool and workpiece are animated on the PC monitor by preparing NC verification module. Finally, optimal cutting conditions are determined empirically and those cutting conditions are integrated into this S/W so that the whole process from design to machining can be done automatically.
A Special Purpose FE Program for the Collapse Strength Analysis of Bulk Carrier Corrugated Bulkheads Subject to Accidental Flooding
Jeom-Kee Paik ; Sung-Geun Kim ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 63~73
Due to the collapse of corrugated bulkheads subject to accidental flooding which is thought to be a primary cause of bulk carrier losses International Maritime Organization(IMO), the International Association of Classification Societies(IACS) and the leading classification societies are taking a growing concern for the structural safety of corrugated bulkheads of bulk carriers. To prevent progressive collapse of corrugated bulkhead in flooded condition particularly of forward cargo ho1d they try to make rules which require reinforcement of corrugated bulkhead structure. However, we are still confronted with the urgent problem of more accurate and efficient ultimate strength assessment for corrugated bulkheads. This paper develops a special purpose nonlinear FE program for analyzing progressive collapse behavior of corrugated bulkheads subject to lateral pressure loads. As verification examples, the program is applied to collapse strength analysis of steel corrugated bulkhead test model.
Reliability of Fatigue Life Predictions for Fixed Offshore Structures
Jae-Ohk Lee ; Hyun-Yup Lee ; Yong-Suk Suh ; Jang-Ho Yoon ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 74~82
To evaluate the reliability against fatigue failure of offshore structures, a fatigue reliability analysis model based on the probabilistic approach has been developed. In this model, the simplified method is adopted as a fatigue analysis method. The uncertainties included in the fatigue analysis are considered as random variables and their statistical properties are evaluated as quantitatively as possible using existing data. As an example, the developed fatigue reliability model is applied to the jacket. And then the relative significance of each uncertainty on the probability of fatigue failure is surveyed.
A Probabilistic Corrosion Rate Estimation Model for Longitudinal Strength Members of Tanker Structures
Jeom-Kee Paik ; Young-Eel Park ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 83~93
The twin aims of the present study are to develop a PC program for the statistical analysis of the measured cohesion data and to suggest a probabilistic corrosion rate estimation model for longitudinal members of tanker structures. A data analysis for the corrosion rate statistics(i.e., mean, standard deviation) as a function of the corrosion parameters is established for various structural member categories/locations of interest. Development of the computer program is focused on possible operation together with future addition of more corrosion data as they become available. To investigate the influence of the corrosion protection scheme a series of the corrosion analysis varying the life of coating are carried out and several different corrosion models as a function of time are suggested depending on the coating life.
The Optimum Structural Design of the High-speed Surface Effect Ship using Composite Materials - Minimum Weight Design
Chang-Doo Jang ; Ho-Kyung Kim ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 94~103
Recently, many researches are carried for high-speed and light craft. In this study, the optimum structural design procedure and the computer program are developed to minimize the hull weight of SES(Surface Effect Ship) built of composite materials. Three types of composite materials-Sandwich, Single Skin and Hybrid type- are considered and the efficiency of each type is investigated. In design process, the optimum design of main members is performed at first considering longitudinal strength. And then, the transverse member design is performed considering torsional strength SSDP(Structural Synthesis Design program) of U.S. Navy is adopted for design algorithm and DnV classification nile for design loads and strength criteria. For optimum structural design, ES 1+1 optimization technique is used.
A New Algorithm to Determine Heating Lines for Plate Forming by Line Heating Method
Chang-Doo Jang ; Sung-Choon Moon ;
Journal of the Society of Naval Architects of Korea, volume 35, issue 2, 1998, Pages 104~113
The line heating method is a popular technique used to form ship hull in shipyards. In order to promote shipbuilding productivity, some researchers have made progress in their studies on automatic fabrication system for plate forming. These researches have, however, focused on heat-induced plate deformation with particular mechanical modelings, and do not yet propose the heating paths applicable to actual plate forming process. In this paper, a new algorithm to determine heating lines is developed to simulate the line heating process. The important feature of this algorithm is that it calculates principal curvatures of deflection difference surface which represents difference between target surface and surface in fabrication. Several trials to typical surface types show its usefulness and good applicability to tactical use.