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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 51, Issue 6 - Dec 2014
Volume 51, Issue 5 - Oct 2014
Volume 51, Issue 4 - Aug 2014
Volume 51, Issue 3 - Jun 2014
Volume 51, Issue 2 - Apr 2014
Volume 51, Issue 1 - Feb 2014
Selecting the target year
Mobility Assessment of Equipment Foundation using Fluid-loaded Whole Ship Model
Lee, Dong-Sup ; Cho, Dae-Seung ; Kim, Kookhyun ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 179~183
DOI : 10.3744/SNAK.2014.51.3.179
The fluid loading effect has been investigated for the shipboard equipment foundation mobility with finite element model. For the purpose, two kinds of finite element models for 60m class ship have been developed: global and local model. The former is for low frequency range and the latter for middle frequency range. These finite element models contain added mass explaining fluid loading effect. Added mass has been implemented with virtual mass matrix derived from Laplace equation governing fluid surrounding ship hull. The mobility assessment result for diesel generator foundation of the objective model shows that the fluid loading effect should be considered, especially in low frequency range, to more accurately assess shipboard equipment foundation mobility.
A Study on the Appendages Optimization of a High Speed Semi-Planing Monohull using DOE
Seo, Kwanhee ; Kim, Hyuncheol ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 184~192
DOI : 10.3744/SNAK.2014.51.3.184
The resistance of a high speed monohull can be dramatically increased at the high speed range due to the severe stern trim, spray formation and hull bottom pressure irregularity etc. In order to avoid these demerits associated with this resistance increase, various appendages such as the stern wedge, vertical wedge, stern flap, spray strip etc. have been studied. Each of appendage can control the trim angle and/or improve the resistance performance. If these appendages are combined for finding the maximal resistance reduction, there are enormous combination selections. This paper presents the DOE(Design of experiment) using an orthogonal array in order to decrease the model tests finding the optimum appendage combination. And we evaluate that the method introduced in this paper makes the optimal combination of appendages efficient and time-saving by applying to high speed semi-planing monohull. Here, the maximum speed and the least fuel expense are adopted as the decision criteria.
A New Sampling Method of Marine Climatic Data for Infrared Signature Analysis
Kim, Yoonsik ; Vaitekunas, David A. ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 193~202
DOI : 10.3744/SNAK.2014.51.3.193
This paper presents a new method of sampling the climatic data for infrared signature analysis. Historical hourly data from a stationary marine buoy of KMA(Korean Meteorological Administration) are used to select a small number of sample points (N=100) to adequately cover the range of statistics(PDF, CDF) displayed by the original data set (S=56,670). The method uses a coarse bin to subdivide the variable space (
=243 bins) to make sample points cover the original data range, and a single-point ranking system to select individual points so that uniform coverage (1/N = 0.01) is obtained for each variable. The principal component analysis is used to calculate a joint probability of the coupled climatic variables. The selected sample data show good agreement to the original data set in statistical distribution and they will be used for statistical analysis of infrared signature and susceptibility of naval ships.
A Study on the Generation of Block Projections for the Assembly Shops
Ruy, Won-Sun ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 203~211
DOI : 10.3744/SNAK.2014.51.3.203
To raise the industrial competitiveness in the field of ship-building, it is crucially important that the yard should use production facilities and working space effectively. Among the related works, the management of tremendous blocks' number, the limited area of assembly shops and inefficient personnel and facility management still need to be improved in terms of being exposed to a lot of problems. To settle down these conundrums, the various strategies of block arrangement on the assembly floors have been recently presented and in the results, have increasingly began to be utilized in practice. However, it is a wonder that the sampled or approximated block shapes which usually are standardized projections or the geometrically convex contour only have been prevailed until now. In this study, all parts including the panel, stiffeners, outer shells, and all kinds of outfitting equipment are first extracted using the Volume Primitive plug-in module from the ship customized CAD system and then, the presented system constructs a simpler and more compact ship data structure and finally generates the novel projected contours for the block arrangement system using the adaptive concave hull algorithm.
Structural Reliability Analysis of Subsea Tree Tubing Hanger
Kim, Hyunjin ; Yang, Youngsoon ; Kim, Sunghee ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 212~219
DOI : 10.3744/SNAK.2014.51.3.212
As subsea production has been revived up, the demand of subsea equipment has also been increased. Among the equipment, subsea tree plays a major role in safety. The tubing hanger is one of the most important components in subsea tree. In this study structural reliability analysis on dual bore tubing hanger of subsea tree is performed. The target reliability which is introduced in ISO regulation is used for judging whether tubing hanger is safe or not. The considered loads are working pressure, working temperature and suspended tubing weight. Thermal-stress analysis on tubing hanger is performed and kriging model is created based on the results of FEM analysis. According to von Mises criterion, limit state equation can be estimated. Reliability analysis is performed by using level 2 method and the result is verified by that of Monte Carlo Simulation. For finding most probable failure point, enhanced HL-RF method is adopted. Because the reliability of model doesn't reach target reliability, an improvement measure should be considered. Thus, it is suggested to change the material of tubing hanger main body to AISI 4140.
Research of Design Improvement regarding Foundation Technologies for Floating LNG
Lee, Dong-Hyun ; Ha, Mun-Keun ; Kim, Soo-Young ; Shin, Sung-Chul ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 220~230
DOI : 10.3744/SNAK.2014.51.3.220
Typical technical issues associated with Floating LNG (FLNG: FSRU and LNG FPSO) design are categorized in terms of global performance evaluation. Although many proven technologies developed through LNG carrier and oil FPSO projects are available for FLNG design, we are still faced with several technical challenges to clear for successful FLNG projects. In this paper, some of the challenges encountered during development of the floating LNG facility (i.e. LNG FPSO and FSRU) will be reviewed together with their investigated solution. At the same time, research of design improvement including new LNG-related technologies such as combined containment system will be presented to overcome the unrevealed challenges for the FLNG development.
A Fundamental Study on the Power Prediction Method of Ship by using the Experiment of Small Model
Ha, Yoon-Jin ; Lee, Young-Gill ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 231~238
DOI : 10.3744/SNAK.2014.51.3.231
In this study, the self-propulsion tests are performed in INHA towing tank. And the effective wake characteristics of the KVLCC2 and the KCS models are compared by the experimental results. The form factor is independent of Reynolds number. To estimate the hydrodynamic performance of a full scale ship, the form factor is determined to consider attendant on Reynolds number. In this research, the power predictions are carried out considering the form factor difference of model and full scale ship. The results of this research could be used as one of the fundamental data to the powering performance prediction.
A Heuristic Algorithm for Block Storage Planning in Shipbuilding
Son, Jung-Ryoul ; Suh, Heung-Won ; Ha, Byung-Hyun ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 239~245
DOI : 10.3744/SNAK.2014.51.3.239
This paper deal with the block storage planning problem of storing and retrieving assembly blocks in a temporary storage yard with limited capacity, which is one of the critical managerial problems in shipbuilding. The block storage planning problem is required to minimize the number of relocations of blocks while the constraints for storage and retrieval time windows are satisfied. We first show NP-hardness of the block storage planning problem. Next we propose a heuristic algorithm to generate good quality solutions for larger instances in very short computational time. The proposed heuristic algorithm was validated by comparing the results with the mathematical model presented in the previous study.
Fatigue Strength Assessment of High Manganese Steel for LNG CCS
Lee, Jin-Sung ; Kim, Kyung-Su ; Kim, Yooil ; Yu, Chang-Hyuk ; Park, Jooil ; Kang, Bong-Ho ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 246~253
DOI : 10.3744/SNAK.2014.51.3.246
Liquid natural gas is stored and transported inside cargo tank which is made of specially designed cryogenic materials such as 9% Ni steel, Al5083-O alloy and SUS304 and so on. The materials have to keep excellent ductile characteristics under the cryogenic environment, down to -163oC, in order to avoid the catastrophic sudden brittle fracture during the operation condition. High manganese steel is considered to be the promising alternative material that can replace the commonly used materials mentioned above owing to its cost effectiveness. In line with this industrial need, the mechanical properties of the high manganese steel under both room and cryogenic environment were investigated in this study focused on its tensile and fatigue behavior. In terms of the tensile strength, the ultimate tensile strength of the base material of the high manganese steel was comparable to the existing cryogenic materials, but it turned out to be undermatched one when welding is involved in. The fatigue strength of the high manganese steel under room temperature was as good as other cryogenic materials, but under cryogenic environment, slightly less than others though better than Al 5083-O alloy.
A Comparative Analysis of Sea Ice Material Properties in the Amundsen Sea, Antarctica
Choi, Kyungsik ; Kim, Hyun Soo ; Ha, Jung Seok ; Lee, Chun-Ju ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 254~258
DOI : 10.3744/SNAK.2014.51.3.254
Field trial in ice-covered sea is one of the most important tasks in the design of icebreaking ships. To correctly estimate ice load and ice resistance on ship's hull, It is essential to understand the material properties of sea ice during ice field trials and to perform the proper experimental procedure by gathering sea ice data. A measurement of sea ice properties was conducted during February and March of 2012 with the Korean Icebreaking research vessel "ARAON" in the Amundsen Sea, Antarctica. This paper describes a test procedure to obtain sea ice data which provide basic information to estimate ice loads and icebreaking performance of the ship. The data gathered from sea ice field trials during the 2012 Antarctic voyage of the ARAON includes ice temperature/salinity/density and the compressive/flexural strength of sea ice. This paper analyses the gathered Antarctic sea ice material properties comparing with the previous data obtained during ARAON's Arctic and Antarctic voyages in 2010.
Vortex Cavitation Inception Delay by Attaching a Twisted Thread
Park, Sang-Il ; Lee, Seung-Jae ; You, Guek-Sang ; Suh, Jung-Chun ;
Journal of the Society of Naval Architects of Korea, volume 51, issue 3, 2014, Pages 259~264
DOI : 10.3744/SNAK.2014.51.3.259
Tip vortex cavitation (TVC) is important for naval ships and research vessels that require raising the cavitation inception speed to maximum possible values. The concepts for alleviating the tip vortex are summarized by Platzer and Souders (1979), who carried out a thorough literature survey. Active control of TVC involves the injection of a polymer or water from the blade tip. The main effect of such mass injection (both water and polymer solutions) into the vortex core is an increase in the core radius, consequently delaying TVC inception. However, the location of the injection port needs to be selected with great care in order to ensure that the mass injection is effective in delaying TVC inception. In the present study, we propose a semi-active control scheme that is achieved by attaching a thread at the propeller tip. The main idea of a semi-active control is that because of its flexibility, the attached thread can be sucked into the low-pressure region closer to the vortex core center. An experimental study using a scale model was carried out in the cavitation tunnel at the Seoul National University. It was found that a flexible thread can effectively suppress the occurrence of TVC under the design condition for a model propeller.