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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 48, Issue 6 - Dec 2011
Volume 48, Issue 5 - Oct 2011
Volume 48, Issue 4 - Aug 2011
Volume 48, Issue 3 - Jun 2011
Volume 48, Issue 2 - Apr 2011
Volume 48, Issue 1 - Feb 2011
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A Comparative Study on Mechanical Behavior of Low Temperature Application Materials for Ships and Offshore Structures
Park, Woong-Sup ; Kang, Ki-Yeob ; Chun, Min-Sung ; Lee, Jae-Myung ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 189~199
DOI : 10.3744/SNAK.2011.48.3.189
Austenite stainless steel(ASS), aluminum alloy and nickel steel alloy are the most widely used in many cryogenic applications due to superior mechanical properties at low temperature. The Face-Centered Cubic(FCC) and Hexagonal Close-Packed(HCP) materials are used for the primary and secondary insulation barrier of Liquefied Natural Gas(LNG) carrier tank and various kinds of LNG applications currently. In this study, tensile tests of ASS, aluminum alloy and nickel steel alloy were carried out for the acquisition of quantitative mechanical properties under the cryogenic environment. The range of thermal condition was room temperature to
and strain rate range was 0.00016/s to 0.01/s considering the dependencies of temperatures and strain rates. The comprehensive test data were analyzed in terms of the characteristics of mechanical behavior for the development of constitutive equation and its application.
Development of Temperature and Strain-Rate Dependent Unified Constitutive Equation for Ships and Offshore Structures
Park, Woong-Sup ; Kim, Jeong-Hyeon ; Chun, Min-Sung ; Lee, Jae-Myung ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 200~206
DOI : 10.3744/SNAK.2011.48.3.200
The mechanical properties of the most widely used cryogenic materials, i.e. austenitic stainless steel (ASS), aluminum alloy and invar steel, strongly depend on temperatures and strain rates. These phenomena show very complicated non-linear behaviors and cannot be expressed by general constitutive equation. In this study, an unified constitutive equation was proposed to represent the effect of temperature and strain rate on the materials. The proposed constitutive equation has been based on Tomita/Iwamoto and Bodner/Partom model for the expression of 2nd hardening due to martensite phase transformation of ASS. To simulate ductile fracture, modified Bodner/Chan damage model was additionally applied to the model and the model validity was verified by comparison of experimental and simulation results.
Integration of Ontology Model and Product Structure for the Requirement Management of Building Specification
Kim, Seung-Hyun ; Lee, Jang-Hyun ; Han, Eun-Jung ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 207~214
DOI : 10.3744/SNAK.2011.48.3.207
Ship design requirements described in the building specification should be reflected in the design process. This paper identifies the configuration of requirements mentioned in the building specification using Ontology Representation Language (OWL). Ontology-based semantic search system specifies the requirement items. Through this extraction, building specifications mentioned for each entry are configured to the tree. Tracking requirements for ship design and a set of procedures to instruct is also used for the V model of systems engineering. The semantic search engine of robot agent and ontology can search the requirements specification document and extract the design information. Thereafter, design requirements for the tracking model that proposes the relationship between the associated BOM(bill of material) and product structure.
Basic Design System Centered on Product Structure for Improvement of Naval Ship Acquisition Systems
Oh, Dae-Kyun ; Min, Young-Ki ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 215~221
DOI : 10.3744/SNAK.2011.48.3.215
To improve the naval ship acquisition process, systems engineering, modeling and simulation, etc. have been introduced, and there has been ongoing research on acquisition systems for effective support of it. However, due to characteristics of the naval ship acquisition process, development process mainly carried out at a shipyard such as basic design, detailed design, construction and test is difficult to integrate with the acquisition systems of IPT(Integrated Project Team). In addition, research aimed to improve this is rather lacking. In this paper, the naval ship product structure concept proposed in previous research was applied to the basic design system at shipyard, and basic research for expanding the coverage of naval ship acquisition systems to the basic design phase is performed. A data structure of modeling system appropriate to the basic design phase was proposed through research findings and the prototype system based on it was implemented.
Computational Study of the Scale Effect on Resistance and Propulsion Performance of VLCC
Choi, Jung-Eun ; Kim, Jung-Hun ; Lee, Hong-Gi ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 222~232
DOI : 10.3744/SNAK.2011.48.3.222
This article examines the scale effect of the flow characteristics, resistance and propulsion performance on a 317k VLCC. The turbulent flows around a ship in both towing and self-propulsion conditions are analyzed by solving the Reynolds-averaged Navier-Stokes equation together with the application of Reynolds stress turbulence model. The computations are carried out in both model- and full-scale. A double-body model is applied for the treatment of free surface. An asymmetric body-force propeller is used. The speed performances including resistance and propulsion factors are obtained from two kinds of methods. One is to analyze the computational results in model scale through the revised ITTC' 78 method. The other is directly to analyze the computational results in full scale. Based on the computational predictions, scale effects of the resistance and the self-propulsion factors including form factor, thrust deduction fraction, effective wake fraction and various efficiencies are investigated. Scale effects of the streamline pattern, hull pressure and local flow characteristics including x-constant sections, propeller and center plane, and transom region are also investigated. This study presents a useful tool to hull-form and propeller designers, and towing-tank experimenters to take the scale effect into consideration.
Experimental Study on the Vortical Flow Behind 2-D Blade with the Variation of Trailing Edge Shape
Paik, Bu-Geun ; Kim, Ki-Sup ; Moon, Il-Sung ; Ahn, Jong-Woo ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 233~237
DOI : 10.3744/SNAK.2011.48.3.233
In the present experiments, vortical structures behind the hydrofoil trailing edge are visualized and analyzed as an elementary study for propeller singing phenomena. Two sorts of hydrofoil are selected for the measurement of shedding vortices. One was KH45 hydrofoil section and the other is KH45 with the truncated trailing edge that is positioned at X/C = 0.9523(C=chord length). Assuming the Strouhal number of 0.23, the shedding frequencies of vortices are extracted by analyzing the boundary layer thickness and the flow speed. The frequency distribution of shedding vortices is obtained with the variation of angle-of-attack while the flow speed is fixed to 8m/s. The truncation of the trailing edge makes the frequency of shedding vortices about 120Hz lower than that of original trailing edge and makes the vorticity value higher than the original trailing edge.
Experiments and Finite Element Analysis for the Estimation of Stress Relief in Welded Structures
Yang, Yong-Sic ; Kang, Joong-Kyoo ; Lee, Jang-Hyun ; Kim, Sung-Chan ; Hwang, Se-Yum ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 238~245
DOI : 10.3744/SNAK.2011.48.3.238
Welding inevitably introduces the residual stresses which affect the fatigue strength of the joint structure. The mitigation of fatigue strength depends on the residual stress magnitude and distribution. Stress relief analyses are of practical interest for all cyclic loaded welded structures, such as ships and offshore structures. In order to estimate the effects of relaxation of residual stresses in the welded structure, this paper presents a finite element analysis procedure and experimental results for the welded structure. Cruciform specimens joint by MAG welding have been tested to measure the released stress. Relieved welding residual stresses obtained by finite element analysis are compared with those measured by experiment.
Residual Longitudinal Strengths of Asymmetrically Damaged Ships
Choung, Joon-Mo ; Lee, Min-Seong ; Jeon, Sang-Ik ; Nam, Ji-Myung ; Ha, Tae-Bum ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 246~253
DOI : 10.3744/SNAK.2011.48.3.246
This paper presents estimation of deterministic damage extents and locations due to collision and grounding which are defined by ABS guideline and DNV ship rules. It is noted that the overall extents of damages from DNV are larger than those from ABS. Nonlinear FEAs are carried out to predict residual longitudinal strength of hull girder with asymmetric severe damages. The accuracy of the applied FEA procedure is proved by comparing FEA result with test result of a 1/3-scaled frigate. The investigated vessels are a VLCC and a large-sized bulker for which evenly distributed heeling angles from
due to damage-induced flooding are taken into account. The reduction ratios of the ultimate residual strength for the damaged cases to those for the intact sagging case are shown. It is proved that the grounding damage case under DNV assumption reveals most critical the residual strength. The design formulas are presented to assure minimum residual ultimate moment after damage.
Strength Characteristics of Arctic Sea Ice from Ice Field Tests of the Icebreaking Research Vessel ARAON
Choi, Kyung-Sik ; Lee, Chun-Ju ; Rim, Chae-Whan ; Kim, Hyun-Soo ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 254~259
DOI : 10.3744/SNAK.2011.48.3.254
The first Korean-made icebreaking research vessel "ARAON" had her second sea ice trial in the Arctic Ocean in Aug. 2010 after her first voyage to Antarctic Ocean in Jan. 2010 to gather various material and strength characteristics of sea ice. This is a detail report of ARAON 2010 summer Arctic voyage and this paper describes a standard test procedure to obtain proper sea ice data which provide basic information to estimate ice loads and icebreaking performance of the ship. The data gathered from sea ice in the Chukchi Sea and Beaufort Sea during the Arctic voyage of the ARAON includes ice temperature/salinity and the compressive/flexural strength of sea ice. This paper analyses the gathered sea ice data in comparison with data from the first voyage of the ARAON during her Antarctic Sea ice trial.
Vortex-Induced Vibration of Simple Slender Structure Using Cartesian Mesh
Han, Myung-Ryoon ; Ahn, Hyung-Teak ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 260~266
DOI : 10.3744/SNAK.2011.48.3.260
For long slender offshore structures, such as cables and pipe lines, their interaction with surrounding fluid flow becomes an important issue for global design of ocean systems. We employ a long circular cylinder as a representative case of slender offshore structure. A flexibly mounted cylinder in cross-flow generates complex vortex shedding and results in oscillation of the structure. In this paper, flow behind a circular cylinder at Re=100 is simulated. The vortex shedding pattern and flow induced motion are examined in the cross flow configuration as well as with various yaw-angled configurations. The "Lock-in" phenomenon is also observed when reduced velocity is approximately 4.0. The MAC Grid system, which is the typical grid system for Cartesian mesh and pressure correction methods, are used for solving the incompressible Navier-Stokes equations. Predictor/Corrector method is applied for obtaining a non-linear response of structure at the flexibly mounted. The existance and motion of the body is represented by the immersed boundary technique.
Prediction of Maneuverability of KCS with 4 Degrees of Freedom
Kim, Yeon-Gyu ; Yeo, Dong-Jin ; Son, Nam-Sun ; Kim, Sun-Young ; Yun, Kun-Hang ; Oh, Byeong-Ik ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 267~274
DOI : 10.3744/SNAK.2011.48.3.267
This paper presents the results of prediction of maneuverability of KCS about 4 degree of freedom(DOF) including roll motion. The prediction is carried out by CPMC captive model test. The CPMC(Computerized Planar Motion Carriage) with captive model test equipment including roll moment gage is installed at Ocean Engineering Tank of MOERI. KCS is the container ship open to the world by MOERI. To predict the 4 DOF maneuverability of a ship some tests with roll angle are conducted. And the prediction results of maneuverability by simulation are compared with the results of free running model test. The simulation results agree well with those of free running model tests.
Prediction of Material Behavior and Failure of Fresh Water Ice Based on Viscoplastic-Damage Model
Choi, Hye-Yeon ; Lee, Chi-Seung ; Lee, Jong-Won ; Ahn, Jae-Woo ; Lee, Jae-Myung ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 275~280
DOI : 10.3744/SNAK.2011.48.3.275
In the present study, a unified viscoplastic-damage model has been applied in order to describe the mechanical characteristics of fresh water ice such as nonlinear material behavior and volume fraction. The strain softening phenomenon of fresh water ice under quasi-static compressive loading has been evaluated based on unified viscoplastic model. The material degradation such as growth of slip/fraction has quite close relation with material inside damage. The volume fraction phenomenon of fresh water ice has been identified based on volume fraction (nucleation and growth of damage) model. The viscoplastic-damage model has been transformed to the fully implicit formulation and the discretized formulation has been implemented to ABAQUS user defined subroutine (User MATerial: UMAT) for the benefit of application of commercial finite element program. The proposed computational analysis method has been compared to uni-axial compression test of fresh water ice in order to validate the compatibilities, clarities and usefulness.
Development of a New Simplified Algorithm for Residual Longitudinal Strength Prediction of Asymmetrically Damaged Ships
Choung, Joon-Mo ; Nam, Ji-Myung ; Lee, Min-Seong ; Jeon, Sang-Ik ; Ha, Tae-Bum ;
Journal of the Society of Naval Architects of Korea, volume 48, issue 3, 2011, Pages 281~287
DOI : 10.3744/SNAK.2011.48.3.281
This paper explains the basic theory and a new development of for the residual strength prediction program of the asymmetrically damaged ships, being capable of searching moment-curvature relations considering neutral axis mobility. It is noted that moment plane and neutral axis plane should be separately defined for asymmetric sections. The validity of the new program is verified by comparing moment-curvature curves of 1/3 scaled frigate model where the results from new algorithm well coincide with experimental and nonlinear FEA results for intact condition and with nonlinear FEA results for damaged condition. Applicability of new algorithm is also verified by applying VLCC model to the newly developed program. It is proved that reduction of residual strengths is visually presented using the new algorithm when damage specifications of ABS, DNV and IMO are applied. It is concluded that the new algorithm shows very good performance to produce moment-curvature relations with neutral axis mobility on the asymmetrically damaged ships. It is expected that the new program based on the developed algorithm can largely reduce design period of FE modeling and increase user conveniences.