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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
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Journal DOI :
The Society of Naval Architects of Korea
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Volume & Issues
Volume 47, Issue 6 - Dec 2010
Volume 47, Issue 5 - Oct 2010
Volume 47, Issue 4 - Aug 2010
Volume 47, Issue 3 - Jun 2010
Volume 47, Issue 2 - Apr 2010
Volume 47, Issue 1 - Feb 2010
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A Study on the Improvement of Resistance Performance for G/T 4.99ton Class Korean Coastal Fishing Boats
Yu, Jin-Won ; Lee, Young-Gill ; Jee, Hyun-Woo ; Park, Ae-Seon ; Choi, Young-Chan ; Ha, Yoon-Jin ; Jeong, Kwang-Leol ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 757~762
DOI : 10.3744/SNAK.2010.47.6.757
Korean fishing boats have had appropriate hull forms for the safety, stability and convenience of fishing ability. However, Korean fishermen are recently concerned about the resistance performance and speed of Korean fishing boats, because the prices of fuel oil are gradually risen, also the exhausting of fish resources and the demand of high speed fishing boats are increased. Therefore, the necessity of the study on the improvement of resistance performance for Korean small coastal fishing boats is gradually increased. This study compares the hull form characteristics of Korean fishing boats with those of Japanese fishing boats, and the hull form of a representative Korean fishing boat is modified. From the modification of the hull form parameters for the Korean fishing boat, the improvement of resistance performances is evaluated. Moreover, the increase of resistance performances is also achieved from the modification of local characteristics for the hull form of the Korean fishing boat. A computational method and ship model tests in towing tank are used for the conformations of the improvement of resistance performance.
Automatic Tool Development for Initial Hull Form Design
Lee, Ju-Hyun ; Rhee, Shin-Hyung ; Jun, Dong-Su ; Chi, Hye-Ryoun ; Kim, Yong-Soo ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 763~769
DOI : 10.3744/SNAK.2010.47.6.763
Thanks to the rapid advancement of computational power and development of numerical methods, Computational fluid dynamics techniques are being used widely for the prediction of ship resistance performance. In the present study, an automatic tool was developed to facilitate hull form modification, consequent mesh generation, and flow analysis for parametric study. It is a tedious job to go back and forth between geometry modification and mesh generation for every hull form variation. With the developed tool, users can make multiple hull form variation and their hull form performance prediction easily in a few simple steps. The verification of the developed tool was done by applying it to resistance performance parametric study of a generic POD propulsion cruise ship with different lengths of bow and stern. It is believed that the tool can be extended to more sophisticated hull form variation and help optimize the ship performance more efficiently.
Propeller Tip Vortex Cavitation Control Using Water Injection
Lee, Chang-Sup ; Han, Jae-Moon ; Kim, Jin-Hak ; Ahn, Byoung-Kwon ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 770~775
DOI : 10.3744/SNAK.2010.47.6.770
As considerable interests in noise emission from the ships have been increased, control of the propeller cavitation generating vibration and radiating noise is looming large. In general, the tip vortex cavitation is first produced in case of full scale propellers, and noise levels rise dramatically from that moment. In order to reduce induced noise from the tip vortex cavitation and hence increase the cavity inception speed, we propose the mass injection method. Water injected from the propeller tip decreases rotating speed of the tip flow, and it restrains growing the tip vortex cavity. Experimental investigations of the model tests carried out in a large cavitation tunnel show that the tip vortex cavitation is effectively controled by water injection from the propeller tip.
Development of a Simple Manoeuvring Model for Ship-handling Simulator by Analytical Methods
Kim, Dong-Jin ; Yeo, Dong-Jin ; Rhee, Key-Pyo ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 776~781
DOI : 10.3744/SNAK.2010.47.6.776
In the ship-handling simulator, it is important for a ship manoeuvring model to represent the dynamic characteristic of a ship and to be simple for reducing calculation time. Especially, even if principal dimensions of a ship are given in initial design stage, or manoeuvring test data are only given by model or real ship`s trials, simulations are often needed to check the manoeuvrability of a ship. In this paper, a simple manoeuvring model based on turning test data of a ship is mathematically developed. And the simulation results are verified by comparing with turning test results of a real ship.
Characteristics of Forces upon Two-dimensional Circular Cylinder by External Singularities
Lee, Seung-Joon ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 782~786
DOI : 10.3744/SNAK.2010.47.6.782
Thrust deduction related to the prediction of power performance of a ship is rather resistance increase, and as a preliminary study for it forces upon a circular cylinder in a uniform flow of ideal fluid due to singularities located behind it are investigated. The circle theorem is used to get the complex velocity potential for the flow field under consideration, and the Blasius theorem is applied to obtain forces upon the circular cylinder. As singularities sinks, point vortices and dipoles and their combinations are treated.
, standing for the strength of a singularity, and
, representing the distance between the cylinder and the singularity, are important small parameters for the resistance and lateral forces. For sinks or point vortices it is shown that the dimensionless forces upon the cylinder is O(
A Study on the Performance of Waterjet Propulsion System for Small Naval Ship
Kim, Kyoung-Bae ; Cho, Dong-Joo ; Park, Myung-Ku ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 787~791
DOI : 10.3744/SNAK.2010.47.6.787
This paper describes the performance of small waterjet propulsion system and show the influence of performance for nozzle shape and area. The installed engine sets a limit on maximum power in below 1800 rpm for fuel saving. Our designated target is reached by redesign of the impeller considering engine characteristics and extention of nozzle pararell part. The results of the full-scale ships are compared with thoes of the model test. In the future, those experimental data will be applied to the relation study between engine characteristics and powering performance prediction.
Application of Plastic Analysis Method to Ship Grillage Design
Kim, Ki-Sung ; Shin, Sung-Uk ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 792~802
DOI : 10.3744/SNAK.2010.47.6.792
A plastic analysis method is commonly used in ship and offshore structural system to utilize the ultimate strength. In this paper, the basic principle of plastic analysis method is applied to ship grillages such as transverse oil-tight bulkheads. The main emphasis is placed on the optimum arrangement of grillage system to give minimum weight. Additional parametric study is carried out to find the effect of various arrangement of grillage system. The above methods are applied to oil-tight bulkhead design, and results are compared with the existing one.
Implementing Framework for Transfer Function-based Ship Underwater Radiated Noise Analysis
Kim, Kook-Hyun ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 803~807
DOI : 10.3744/SNAK.2010.47.6.803
The transfer function method is a widely used in the analysis of underwater radiated noise of ships because it is simple to implement and gives a simple way in the design stage requiring trade-off studies on various kinds of noise sources. In this study, a framework is implemented based on the transfer function method. The framework is interfaced to a software providing transfer functions of hull force to underwater radiated noise. The transfer function-based underwater radiated noise analysis approach is reviewed and the implemented framework structure is described. As an example, a numerical calculation of a virtual ship is carried out and its results are investigated in terms of applicability to real ship design project.
A Study on the Finite Element Modeling and Analytical Parameters for the Dynamic Stiffness Evaluation of Shipboard Equipment Foundations
Kim, Kook-Hyun ; Kim, Yun-Hwan ; Choi, Tae-Muk ; Choi, Sung-Won ; Cho, Dae-Seung ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 808~812
DOI : 10.3744/SNAK.2010.47.6.808
This paper studies the finite element modeling and analytical parameters for the numerical evaluation of dynamic stiffness of large foundation for shipboard equipments such as marine diesel engine. For the purpose, numerical method and procedure to evaluate the dynamic stiffness are established based on the impact test method, which are applied for the dynamic stiffness evaluation of a real diesel generator foundation of ship. Numerical investigations compared with the measured data are carried out to evaluate the effects of modeling ranges of ship substructure, finite element sizes, lower support structures and damping coefficients. From the results, modeling and analytical parameters for proper evaluation of dynamic stiffness of large foundation of shipboard equipment are suggested.
Fatigue Damage Combination for Spread Mooring System under Stationary Random Process with Bimodal Spectrum Characteristics
Lim, Yu-Chang ; Kim, Kyung-Su ; Choung, Joon-Mo ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 813~820
DOI : 10.3744/SNAK.2010.47.6.813
The spread mooring system for FPSO is developed to explore deep sea area, in which swell is dominant. It is known that the tension response of mooring lines in this sea area shows bimodal spectrum. Assuming normal distribution of tension profile and Rayleigh distribution of tension amplitude, the power spectral density function (PSD) of the mooring tension under the bimodal stationary random process is applied for the calculation of spectrum fatigue. Three popular methods, which are simple summation method, combined spectrum method and Jioa-Moan method, are used to combine fatigue damages from bimodal spectrum characteristics. Each damage value is compared with damage using Rainflow Cycle Counting (RCC) method which is believed to be close to exact solution. Vanmarcke` parameter and RMS(Root Mean Square) ratio are employed to assess relative damage variations between from RCC method and from three combination methods. Finally the most reliable fatigue damage combining method for spread mooring system is suggested.
Numerical Analysis of Welding Residual Stresses for Ultra-Thick Plate of EH40 Steel Joined by Tandem EGW
Hwang, Se-Yun ; Lee, Jang-Hyun ; Kim, Byung-Jong ; Yang, Yong-Sik ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 821~830
DOI : 10.3744/SNAK.2010.47.6.821
Deck plates and hatch coming of large container carrier and offshore structures are joined by ultra-thick plates whose thickness is more than 60mm. Traditionally FCAW has been used to join the thick plates in butt joint. However, FCAW has been replaced with EGW since the welding efficiency of EGW is higher than that of FCAW. Tandem EGW using two electrodes has been applied to vertical position welding by several shipyards. EGW requires one or two layers of bead whereas FCAW requires more than 20 layers of weld bead in thick welding. However, high welding residual stresses are generated by EGW since it uses higher heat input than FCAW. In the present study, a finite element model is suggested to predict the residual stresses induced by the tandem EGW. Butt specimen of EH40 TMCP shipbuilding steel plates vertical welding was modeled by a three-dimensional model. Residual stresses were measured by X-ray diffraction method and to verify the numerical result. The results show a good agreement with experimental result.
A Study on the Application of Engineering Design Problem using Web Service
Park, Chang-Kyu ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 831~835
DOI : 10.3744/SNAK.2010.47.6.831
Currently, engineering design is carried out in a distributed manner geographically or physically. This imposes new requirements on the computational environments, such as efficient integration and collaboration in the Internet and network environments. Meanwhile, Web-based distributed design has led new paradigms in design and manufacturing fields. For example, Web-based technologies have reduced the product development time and to ensure a competitive product in order to exchange and interact of real-time design information that integrates the distributed design environment between departments as well as companies via Internet and Web. Hence, efficient data communication for design information sharing is the basis for collaborative systems in the distributed environments. Design data communication techniques such as CORBA, DCOM, and JAVA RMI have been considered in the existing research, but these techniques have some disadvantages such as limitations of interoperability and firewall problems. This paper presents the application of engineering design problems in which distributed design information resources are integrated and exchanged using Web Service for supporting XML and HTTP without interoperability and firewall problems.
A Study on Safety System for Blasting Workers using Real Time Location System in the Shipyard
Yun, Won-Jun ; Ro, Young-Shic ; Cho, Sang-Bock ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 836~842
DOI : 10.3744/SNAK.2010.47.6.836
Safety system including location monitoring system for blasting workers was studied. Positioning performance of the location monitoring system was highly dependent on communication protocol and the number of access points in the blasting cell. RTLS(Real Time Location System) is an important technology to develop the location information of workers and variously used to enhance workers safety. Location monitoring system with Cell-ID and RSSI wireless communication technology was verified to have a proper positioning performance for the steel block application.
Study on Section Properties of Asymmetric-Sectioned Vessels
Choung, Joon-Mo ; Kim, Young-Hun ;
Journal of the Society of Naval Architects of Korea, volume 47, issue 6, 2010, Pages 843~849
DOI : 10.3744/SNAK.2010.47.6.843
This paper presents definition of symmetry of a ship section where three symmetries are proposed: material, geometric, and load symmetries. Precise terminologies of centroid, moment plane, and neutral axis plane are also defined. It is suggested that force vector equilibrium as well as force equilibrium are necessary condition to determine new position of neutral axis due to translational and rotational mobility. It is also stated that new reference datum of ENMP(elastic neutral moment plane), PNMP(fully plastic moment plane), ENAP(elastic neutral axis plane), and INAP(inelastic neutral moment plane) are required to define asymmetric section properties such as second moment of area, elastic section modulus, yield moment, fully plastic moment, and ultimate moment. Since collision-induced damage and flooding-induced biaxial bending moment produce typical asymmetry of section, the section properties are calculated for a typical VLCC. Geometry asymmetry is determined from ABS and DNV rules and two moment planes of 0/30 degs are assumed for load asymmetry. It is proved that the property reduction ratios directly calculated from second moment of area are usually larger than area reduction ratio. Reduction ratio of ultimate moment capacity shows almost linearly proportional to area reduction ratio. Mobility of elastic and inelastic neutral axis planes is visually provided.