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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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International Journal of Ocean System Engineering
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 2, Issue 4 - Nov 2012
Volume 2, Issue 3 - Aug 2012
Volume 2, Issue 2 - May 2012
Volume 2, Issue 1 - Feb 2012
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SPH Modeling of Surge Overflow over RCC Strengthened Levee
Li, Lin ; Amini, Farshad ; Rao, Xin ; Tang, Hongwu ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 200~208
DOI : 10.5574/IJOSE.2012.2.4.200
Surge overflow may cause damage on earthen levees. Levee strengthened on the levee crest and landward-side slope can provide protection against the erosion damage induced by surge overflow. In this paper, surge overflow of a roller compacted concrete RCC strengthened levee was studied in a purely Lagrangian and meshless approach, the smoothed particle hydrodynamics (SPH) method. After verifying the developed model with analytical solution and comparing the results with full-scale experimental data, the roughness and erosion parameters were calibrated. The water thickness, flow velocity, and erosion depth at crest, landward-side slope and toe were calculated. The characteristics of flow hydraulics and erosion on the RCC strengthened levee are given. The results indicate that the RCC strengthened levee can resist erosion damage for a long period.
Corrosion Characteristics of Welding Zone by Types of Repair Welding Filler Metals and Post Weld Heat Treatment
Lee, Sung-Yul ; Moon, Kyung-Man ; Lee, Yeon-Chang ; Kim, Yun-Hae ; Jeong, Jae-Hyun ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 209~213
DOI : 10.5574/IJOSE.2012.2.4.209
Recently, the fuel using in the diesel engines of marine ships has been changed to a low quality of heavy oil because of the steady increase in the price of oil. Therefore, the wear and corrosion in all parts of the engine such as the cylinder liner, piston crown, and spindle and seat ring of exhaust valves has correspondingly increased. The repair welding of a piston crown is a unique method for prolonging its lifetime from an economic point of view. In this case, filler metals with a high corrosion and wear resistance are mainly being used for repair welding. However, often at a job site on a ship, a piston crown is actually welded with mild filler metals. Therefore, in this study, mild filler metals such as CSF350H, E8000B2, and 435 were welded to SS401 steel as the base metal, and the corrosion properties of the weld metals with and without post weld heat treatment were investigated using some electrochemical methods in a 0.1%
solution. The weld metal welded with CSF350H filler metal exhibited the best corrosion resistance among these filler metals, irrespective of the heat treatment. However, the weld metal zones of the E8000B2 and 435 filler metals exhibited better and worse corrosion resistance with the heat treatment, respectively. As a result, it is suggested that in the case of repair welding with CSF350H and 435 filler metals, no heat treatment is advisable, while heat treatment is desirable if E8000B2filler metal is used with repair welding.
A Study on Collaborative Environment for Development of Submarine: Focusing on Modeling System for Digital Submarine
Oh, Dae-Kyun ; Shin, Jong-Gye ; Jeong, Yeon-Hwan ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 214~222
DOI : 10.5574/IJOSE.2012.2.4.214
The shipbuilding process is changing due to changes in the development environment and technological requirements for military ships. This would also hold true for a submarine, because its shipbuilding process includes complicated design and construction conditions. System improvement efforts for the design and construction of military ships have continued with the goal of overcoming these conditions. At present, the Korea Navy is developing a 3,000 ton-class Korean type submarine, and its design is progressing by the introduction of a full 3D-ship CAD system. Although the 3D modeling system was introduced for effective design realization through the introduction of collaborative design and active utilization of M&S (modeling and simulation), the introduction effects are not yet generally obvious, according to the characteristics of ship design. The present paper discusses the collaborative environment for developing a submarine to enhance this. This paper proposes the architecture and data structure of a system for realizing collaborative design and discusses a case system developed on the basis of this.
Development of Rotational Motion Estimation System for a UUV/USV based on TMS320F28335 microprocessor
Tran, Ngoc-Huy ; Choi, Hyeung-Sik ; Kim, Joon-Young ; Lee, Min-Ho ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 223~232
DOI : 10.5574/IJOSE.2012.2.4.223
For the accurate estimation of the position and orientation of a UUV (unmanned underwater vehicle), a low-cost AHRS (attitude heading reference system) was developed using a low-cost IMU (inertial measurement unit) sensor which provides information on the 3D acceleration, 3D turning rate and 3D earth-magnetic field data in the object coordinate system. The main hardware system is composed of an IMU sensor (ADIS16405) and TMS320F28335, which is coded with an extended kalman filter algorithm with a 50-Hz sampling frequency. Through an experimental gimbal device, good estimation performance for the pitch, roll, and yaw angles of the developed AHRS was verified by comparing to those of a commercial AHRS called the MTi system. The experimental results are here presented and analyzed.
Development of Preliminary Design Model for Ultra-Large Container Ships by Genetic Algorithm
Han, Song-I ; Jung, Ho-Seok ; Cho, Yong-Jin ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 233~238
DOI : 10.5574/IJOSE.2012.2.4.233
In this study, we carried out a precedent investigation for an ultra-large container ship, which is expected to be a higher value-added vessel. We studied a preliminary optimized design technique for estimating the principal dimensions of an ultra-large container ship. Above all, we have developed optimized dimension estimation models to reduce the building costs and weight, using previous container ships in shipbuilding yards. We also applied a generalized estimation model to estimate the shipping service costs. A Genetic Algorithm, which utilized the RFR (required freight rate) of a container ship as a fitness value, was used in the optimization technique. We could handle uncertainties in the shipping service environment using a Monte-Carlo simulation. We used several processes to verify the estimated dimensions of an ultra-large container ship. We roughly determined the general arrangement of an ultra-large container ship up to 1500 TEU, the capacity check of loading containers, the weight estimation, and so on. Through these processes, we evaluated the possibility for the practical application of the preliminary design model.
Evaluation of Characteristics of CBN Honing Stone for Cylinder Liner Honing of Marine Diesel Engine
Jeong, Jae-Hyun ; Kim, Jong-Sun ; Lee, Yeon-Chang ; Lee, Sung-Yul ; Moon, Kyung-Man ; Kim, Yun-Hae ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 239~243
DOI : 10.5574/IJOSE.2012.2.4.239
The cylinder liner of a low speed engine is one of the most important parts of the marine diesel engines used in merchant ships. However, a sufficient degree of precision in the manufacturing method for these cylinder liners has never existed. Conventional honing stones have always been used for machining large marine cylinder liners. Therefore, it is necessary to develop a honing process that optimizes the honing characteristics. In this study, a CBN honing stone was manufactured to improve the honing performance for a cylinder liner and shorten the processing time, and machining experiments on a practical cylinder liner were carried out. Then, a comparison was made between the CBN honing and honing with a conventional GC stone using parameters such as the honing time, machining quantity, and honing cost. As a result, for a #60 CBN stone, the machining amount was significantly improved compared to the conventional one by about
/min, and in respect to the machining cost, a reduction of about 57% was achieved. However, an improvement in the process with a #800 CBN stone could not be expected because it did not show a significant difference compared to the case of the existing stone. From the above results, if the liner were honed using a CBN honing stone, the rough machining and intermediate processing during an early stage of the honing process were excellent compared to the conventional one. However, we could not find a significant difference in the case of finish honing.
Study on Sliding Wear Characteristics and Processing of MoSi
Park, Sungho ; Park, Wonjo ; Huh, Sunchul ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 244~249
DOI : 10.5574/IJOSE.2012.2.4.244
In this study, a monolithic MoSi2 matrix reinforced with 20 vol% SiC particles, a SiC/MoSi2 composite matrix reinforced with 20 vol% ZrO2 particles, and a ZrO2/MoSi2 composite were fabricated using hot press sintering at
for 1 h under a pressure of 30 MPa. The Vickers hardness and sliding wear resistance of the monolithic MoSi2, ZrO2/MoSi2, and SiC/MoSi2 composite were investigated at room temperature. A wear behavior test was carried out using a disk-type wear tester with a silicon nitride ball. The ZrO2/MoSi2 composite showed an average Vickers hardness value and excellent wear resistance compared with the monolithic MoSi2 and SiC/MoSi2 composite at room temperature.
Validity of Ocean Wave Spectrum Using Rayleigh Probability Density Function
Choi, Young Myung ; Yang, Young Jun ; Kwon, Sun Hong ;
International Journal of Ocean System Engineering, volume 2, issue 4, 2012, Pages 250~258
DOI : 10.5574/IJOSE.2012.2.4.250
The distribution of wave heights is assumed to be a Rayleigh distribution, based on the assumption of a narrow band and Gaussian distribution of wave elevation. The present study was started with doubts about the narrow band assumption. We selected the wave spectra widely used to simulate irregular random waves. The wave spectra used in this study included the Pierson-Moskowitz spectrum, Bretschneider-Mitsuyasu spectrum, and JONSWAP spectrum. The directionality of the waves was considered. The cosine 2-l type directional spreading function and mixed form of the half-cosine 2-s type with Mitsuyasu type directional spreading are considered here to investigate the effects of a directional spreading function on random waves. The simulated wave height distribution is compared with a Rayleigh distribution.