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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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International Journal of Ocean System Engineering
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Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 3, Issue 4 - Nov 2013
Volume 3, Issue 3 - Aug 2013
Volume 3, Issue 2 - May 2013
Volume 3, Issue 1 - Feb 2013
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A Method of Moments Approach for Laminar Boundary Layer Flows
Kinaci, Omer Kemal ; Usta, Onur ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 111~115
DOI : 10.5574/IJOSE.2013.3.3.111
Blasius equation describes the boundary layer formed over a flat plate inside a fluid and this equation is solved numerically by the method of moments which is a type of weighted residual methods. Compared to the traditionally used Runge - Kutta Method, Method of Moments propose a direct solution to Blasius Equation which makes it easier to solve. The obtained solutions show good agreement with the results found in literature and this study aims to demonstrate the power of the method.
Real Time Current Prediction with Recurrent Neural Networks and Model Tree
Cini, S. ; Deo, Makarand Chintamani ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 116~130
DOI : 10.5574/IJOSE.2013.3.3.116
The prediction of ocean currents in real time over the warning times of a few hours or days is required in planning many operation-related activities in the ocean. Traditionally this is done through numerical models which are targeted toward producing spatially distributed information. This paper discusses a complementary method to do so when site-specific predictions are desired. It is based on the use of a recurrent type of neural network as well as the statistical tool of model tree. The measurements made at a site in Indian Ocean over a period of 4 years were used. The predictions were made over 72 time steps in advance. The models developed were found to be fairly accurate in terms of the selected error statistics. Among the two modeling techniques the model tree performed better showing the necessity of using distributed models for different sub-domains of data rather than a unique one over the entire input domain. Typically such predictions were associated with average errors of less than 2.0 cm/s. Although the prediction accuracy declined over longer intervals, it was still very satisfactory in terms of theselected error criteria. Similarly prediction of extreme values matched with that of the rest of predictions. Unlike past studies both east-west and north-south current components were predicted fairly well.
Special Fundamental Fields for Plane Cracks in Weight Function Theory
An, Deukman ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 131~135
DOI : 10.5574/IJOSE.2013.3.3.131
We construct the fundamental fields for 3-D arbitrarily shaped plane cracks in by differentiating with respect to a parameter of the crack. As an application of these fundamental fields, the total elastic energy release rate in combined mode cracking is computed.
Comparative study of Metallic and Polymer Composite Shells for Underwater Vessels Using FEA
Govindaraj, Moorthy ; Narayanarao, Narasimha Murthy Heddale ; Munishaiah, Krishna ; Nagappa, Raghavendra ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 136~141
DOI : 10.5574/IJOSE.2013.3.3.136
The present research was aimed at comparing performance of metallic and polymer composite shells of a typical underwater vessel of length and inner diameter of 1650 mm and 350 mm respectively, based on the critical buckling pressure for operating depth of 1000 m using ANSYS. High strength steel, aluminium alloy, titanium alloy, glass / epoxy and carbon / epoxy materials were examined. The results indicated weight savings of 46 % in carbon/epoxy and 31 % in glass / epoxy when compared with high strength steel, based on the thickness of the shell for sustaining 10 MPa buckling pressure.
Tribological Properties of Carbon/PEEK Composites
Yoon, Sung-Won ; Kim, Yun-Hae ; Lee, Jin-Woo ; Kim, Han-Bin ; Murakami, Ri-Ichi ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 142~146
DOI : 10.5574/IJOSE.2013.3.3.142
In this study, the effect of Carbon/PEEK composites on the tribological properties has been investigated. Also, its validity has been tested in the capacity of alternative materials of the Ti-based materials used for artificial hip joint. Moreover, this work evaluated the mechanical properties according to the fiber ply orientation, along with the fractured surfaces of the carbon/PEEK composites. The composites with a unidirectional orientation had higher tribological properties than those with a multidirectional orientation. This was caused by the debonding between the carbon fiber and the PEEK, which was proportional to the contact area between the sliding surface and the carbon fiber. The friction test results showed that there were no significant differences in relation to the fiber ply orientation. However, the friction properties of the carbon/PEEK composites were higher than those of the carbon/epoxy composites. In addition, the results showed that a composite that slid in a direction normal to the prepreg lay-up direction had a smaller friction coefficient than one that slid in a direction parallel to the prepreg lay-up direction.
Friction and Wear Behavior of Carbon/PEEK Composites according to Sliding Velocity
Yoon, Sung-Won ; Kim, Yun-Hae ; Lee, Jin-Woo ; Kim, Han-Bin ; Murakami, Ri-Ichi ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 147~151
DOI : 10.5574/IJOSE.2013.3.3.147
This study was to correctly estimate the friction and wear behavior of carbon fiber and PEEK sheet composites, and the validity of using them as alternatives to the metal-based materials used for artificial hip joints. Moreover, this work evaluated the friction coefficient according to the fiber ply orientation, along with the fractured surfaces of the carbon/PEEK composites. The unidirectional composites had higher friction coefficients than those multidirectional composites. This was caused by the debonding between the carbon fiber and the PEEK sheet, which was proportional to the contact area between the sliding surface and the carbon fiber. The friction test results showed that there was no significant differences in relation to the fiber ply orientation. However, in a case where the speed was 2.5 m/s, the friction coefficient was relatively large for configuration I. The friction surface of the specimen was analyzed using an electron microscope. In all cases, the debonding of the fiber and PEEK could be confirmed.
Comparison of Mechanical Properties between Carbon/PEEK Composites and Ti Stem for Optimal Design
Yoon, Sung-Won ; Kim, Yun-Hae ; Jung, Min-Kyo ; Murakami, Ri-Ichi ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 152~157
DOI : 10.5574/IJOSE.2013.3.3.152
This study, a new concept design of the stem and aims to determine the suitability of various carbon/PEEK composite designs for artificial hip joints. Shear stress tested with alternative materials of the Ti-based stem for artificial hip joints. In addition, FEA is conducted according to the fiber ply orientation and the load condition for carbon/PEEK composites. The stem shape of two types was designed through the shape normal of the femur. Multidirectional load cases were used for each FEA model. In the case of general shape, the results show that the stress of ply orientation case II was lower than for cases I and III. On the other hand, in the case of the curved shape, ply orientation case I was lowest. In the case of the Ti stem, the stress of the curved shape was 18% lower than the general shape.
Development of Acoustic Target Strength Analysis System for Submarine
Kwon, Hyun-Wung ; Hong, Suk-Yoon ; Jeon, Jae-Jin ; Song, Jee-Hun ;
International Journal of Ocean System Engineering, volume 3, issue 3, 2013, Pages 158~163
DOI : 10.5574/IJOSE.2013.3.3.158
The acoustic target strength (TS) is one of the most important parameters for a submarine`s stealth design. Because modem submarines are larger than their predecessors, TS must be managed at each design stage in order to reduce it. To predict the TS of a submarine, TASTRAN R1 was developed based on a Kirchhoff approximation in a high-frequency range. This program can present TS values that include multi-bounce effect in the exterior and interior of the structure by combining geometric optics (GO) and physical optics (PO) methods, anechoic coating effect by using the reflection coefficient, and response time pattern for a detected target. In this paper, TS calculations for a submarine model with the above effects are simulated by using this developed program, and the TS results are discussed.