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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
Editor in Chief :
Volume & Issues
Volume 29, Issue 6 - Dec 2015
Volume 29, Issue 5 - Oct 2015
Volume 29, Issue 4 - Aug 2015
Volume 29, Issue 3 - Jun 2015
Volume 29, Issue 2 - Apr 2015
Volume 29, Issue 1 - Feb 2015
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Study of Hull Form Development of 5-Ton-Class Catamaran-Type Coastal Fishing Boat for Welfare Accommodation of Fishing Crew
Jeong, Uh-Cheul ; Kim, Hyun-Soo ; Kwon, Soo-Yeon ; Choi, Ji-Hoon ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 405~410
DOI : 10.5574/KSOE.2015.29.6.405
This paper reports the hull form development and resistance performance of a 5-ton-class catamaran-type coastal fishing boat. The weight estimation and preliminary design were basically extracted from existing coastal fishing vessels. In addition, the resistance performance was investigated using a model test in a high-speed circulating water channel and was analyzed in comparison to an existing catamaran fishing vessel. As a result, the modified hull achieved an approximately 30% reduction in resistance compared to the previous hull. The stability or boarding sensitivity of the modified hull form was more stable or comfortable than the original hull form based on a trim and sinkage comparison between the two boats.
Study on Resistance Component of Container Ship According to Trim Conditions
Han, Ki-Min ; Park, Hyun-Suk ; Seo, Dae-Won ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 411~417
DOI : 10.5574/KSOE.2015.29.6.411
The shipping and shipbuilding industries have had business difficulties since the implementation of regulations on the CO
emissions from ships by IMO and the occurrence of the global financial crisis in 2008. Under this global recession, most shipping firms have started to operate their fleets at slow steaming rates with the goal of improving the profit ratio per transported unit. This study analyzed the resistance performance of a 6,800 TEU container ship corresponding to its trim variation with slow steaming, compared with that at its original design speed. Two different grid systems were used for the numerical calculation, one that considered the free surface allowing the capture of the dynamic trim and one that did not. This made it possible to clearly classify each resistance component to provide useful information to hull-form designers. In addition, a form factor assumption method using CFD was used for a reasonable effective power prediction in compliance with the 1978 ITTC performance prediction method. It was found that the total resistance of a 6,800 TEU container ship was reduced by 2.6% in the case of a 1-m trim at the bow at 18 kn.
Fundamental Study for Predicting Ship Resistance Performance Due to Changes in Water Temperature and Salinity in Korea Straits
Seok, Jun ; Jin, Song-Han ; Park, Jong-Chun ; Shin, Myung-Soo ; Kim, Sung-Yong ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 418~426
DOI : 10.5574/KSOE.2015.29.6.418
Recently, shipping operators have been making efforts to reduce the fuel cost in various ways, such as trim optimization and bulb re-design. Furthermore, IMO restricts the hydro-dioxide emissions to the environment based on the EEDI (Energy Efficiency Design Index), EEOI (Energy Efficiency Operational Indicator), and SEEMP (Ship Energy Efficiency Management Plan). In particular, ship speed is one of the most important factors for calculating the EEDI, which is based on methods suggested by ITTC (International Towing Tank Conference) or ISO (International Standardization Organization). Many shipbuilding companies in Korea have carried out speed trials around the Korea Straits. However, the conditions for these speed trials have not been exactly the same as those for model tests. Therefore, a ship’s speed is corrected by measured environmental data such as the seawater temperature, density, wind, waves, swell, drift, and rudder angle to match the conditions of the model tests. In this study, fundamental research was performed to evaluate the ship resistance performance due to changes in the water temperature and salinity, comparing the ISO method and numerical simulation. A numerical simulation of a KCS (KRISO Container ship) with a free-surface was performed using the commercial software Star-CCM+ under three conditions that were assumed based on the water temperature and salinity data in the Korea Straits. In the simulation results, the resistance increased under low water temperature & high salinity conditions, and it decreased under high water temperature & low salinity conditions. In addition, the ISO method showed the same result as the simulation.
Numerical Analysis of Flow around Propeller Rotating Beneath Free Surface
Park, Il-Ryong ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 427~435
DOI : 10.5574/KSOE.2015.29.6.427
This paper provides the numerical results of a simulation of the flow around a propeller working beneath the free surface. A finite volume method is used to solve the unsteady Reynolds averaged Navier-Stokes (URANS) equations, where the wave-making problem is solved using a volume-of-fluid (VOF) method. The numerical analysis focuses on the propeller wake structure affected by the free surface, where we consider another free surface boundary condition that treats the free surface as a rigid wall surface. The propeller wake under the effect of these two free surface conditions shows a reduction in the magnitude of the longitudinal and vertical flow velocities, and its vortical structures strongly interact with the free surface. The thrust and torque coefficient under the free surface effect decrease about 3.7% and 3.1%, respectively. Finally, the present numerical results show a reasonable agreement with the available experimental data.
Study on Coning Motion Test for Submerged Body
Park, Jong-Yong ; Kim, Nakwan ; Rhee, Key-Pyo ; Yoon, Hyeon Kyu ; Kim, Chanki ; Jung, Chulmin ; Ahn, Kyoungsoo ; Lee, Sungkyun ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 436~444
DOI : 10.5574/KSOE.2015.29.6.436
A submerged body is sensitive to changes in the roll moment because of the small restoring moment and moment of inertia. Thus, a method for predicting the roll-related hydrodynamic coefficients is important. This paper describes a deduction method for the hydrodynamic coefficients based on the results of a coning motion test. A resistance test, static drift test, and coning motion test were performed to obtain the coefficients in the towing tank of Seoul National University. The sum of the hydrodynamic force, inertial force, gravity, and buoyancy was measured in the coning motion test. The hydrodynamic force was deduced by subtracting the inertial force, gravity, and buoyancy from the measured force. The hydrodynamic coefficients were deduced using the regression method.
Development of Three Dimensional Fracture Strain Surface in Average Stress Triaxiaility and Average Normalized Lode Parameter Domain for Arctic High Tensile Steel: Part I Theoretical Background and Experimental Studies
Chong, Joonmo ; Park, Sung-Ju ; Kim, Younghun ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 445~453
DOI : 10.5574/KSOE.2015.29.6.445
The stress triaxiality and lode angle are known to be most dominant fracture parameters in ductile materials. This paper proposes a three-dimensional failure strain surface for a ductile steel, called a low-temperature high-tensile steel (EH36), using average stress triaxiality and average normalized lode parameter, along with briefly introducing their theoretical background. It is an extension of previous works by
Choung et al. (2011
Choung and Nam (2013)
, in which a two-dimensional failure strain locus was presented. A series of tests for specially designed specimens that were expected to fail in the shear mode, shear-tension mode, and compression mode was conducted to develop a three-dimensional fracture surface covering wide ranges for the two parameters. This paper discusses the test procedures for three different tests in detail. The tensile force versus stroke data are presented as the results of these tests and will be used for the verification of numerical simulations and fracture identifications in Part II.
Development of Three-Dimensional Fracture Strain Surface in Average Stress Triaxiaility and Average Normalized Lode Parameter Domain for Arctic High Tensile Steel: Part II Formulation of Fracture Strain Surface
Chong, Joonmo ; Park, Sung-Ju ; Kim, Younghun ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 454~462
DOI : 10.5574/KSOE.2015.29.6.454
An extended study was conducted on the fracture criterion by
Choung et al. (2011
Choung and Nam (2013)
, and the results are presented in two parts. The theoretical background of the fracture and the results of new experimental studies were reported in Part I, and three-dimensional fracture surface formulations and verifications are reported in Part II. How the corrected true stress can be processed from the extrapolated true stress is first introduced. Numerical simulations using the corrected true stress were conducted for pure shear, shear-tension, and pure compression tests. The numerical results perfectly coincided with test results, except for the pure shear simulations, where volume locking appeared to prevent a load reduction. The average stress triaxialities, average normalized lode parameters, and equivalent plastic strain at fracture initiation were extracted from numerical simulations to formulate a new three-dimensional fracture strain surface. A series of extra tests with asymmetric notch specimens was performed to check the validity of the newly developed fracture strain surface. Then, a new user-subroutine was developed to calculate and transfer the two fracture parameters to commercial finite element code. Simulation results based on the user-subroutine were in good agreement with the test results.
Fatigue Analysis of 306K Crude Oil Tanker Based on MSC Fatigue
Guo, Wei ; Bae, Dong-Myung ; Cao, Bo ; Qi, Da-Long ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 463~469
DOI : 10.5574/KSOE.2015.29.6.463
Fatigue in the metal used as hull material has always been an important issue. The fatigue phenomenongenerally occurs suddenly in a ship hull, and always causesa large number of casualties and economic losses. This paper presents a study of an assessment method for the fatigue life based on Li’s approach using MSC Fatigue. The details of Li’s approach based on MSC Fatigue are provided. Based on the results of this study, it can be concluded that Li’s approach has several advantages: (1) it allows the wide application of different structural details, (2) is easy to use, and (3) provides accurate results. Finally, Li’s approach can be proven to be feasible for a ship’s fatigue analysis.
Study on Performance Evaluation of Subsea Waterjet Trenching Machine Using Water Tank
Na, Kyoung-Won ; Jo, Hyo-Jae ; Baek, Dong-Il ; Hwan, Jae-Hyuk ; Han, Sung-Hoon ; Jang, Min-Suk ; Kim, Jae-Heui ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 470~474
DOI : 10.5574/KSOE.2015.29.6.470
The demand for subsea cables and pipelines that transfer marine energy resources onshore has recently increased. Laying these underground after trenching is one engineering method to stabilize exposed subsea cables and pipelines. This experimental study found the optimum conditions for operating two types of waterjet arms mounted on an ROV trencher. A waterjet arm for trenching the seabed was scaled down at a ratio of 1:6, and a comparative analysis was conducted using diverse parameters. The results of this research provide a practical fundamental database to assist in making decisions about the ROV trencher performance in advance.
Corrosion Resistance Characteristics of Cr-free Coating Solution for Degraded STS316L
Lee, So-Young ; Kim, Young-Soo ; Jeong, Hee-Rock ; Ahn, Seok-hwan ; Nam, Ki-Woo ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 475~480
DOI : 10.5574/KSOE.2015.29.6.475
In this study, we developed a Cr-free organic/inorganic hybrid solution and investigated its coating properties on degraded STS316L. Both the OIBD-1 solution and OIBD-2 solution had excellent corrosion resistance and adhesion ability. However, the solution had some problems in a boiling water environment. In addition, the flexibility was excellent, and the scratch resistance was relatively good.
Effects of Heat Input and Preheat/interpass Temperature on Strength and Impact Toughness of Multipass Welded Low Alloy Steel Weld Metal
Bang, Kook-soo ; Jung, Ho-shin ; Park, Chan ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 481~487
DOI : 10.5574/KSOE.2015.29.6.481
The effects of the heat input and preheat/interpass temperatures on the tensile strength and impact toughness of multipass welded weld metal were investigated and interpreted in terms of the recovery of the alloying elements and microstructure. Increases in both the heat input and preheat/interpass temperatures decreased the tensile strength of the weld metal. A lower recovery of alloying elements, especially Mn and Si, and smaller area fraction of acicular ferrite in the weld metal were observed in higher heat input welding, resulting in a lower tensile strength. In contrast, only a microstructure difference was observed at a higher preheat/interpass temperature. The impact toughness of the weld metal gradually increased with an increase in the heat input because of the lower tensile strength. However, it decreased again when the heat input was larger than 45 kJ/cm because of the much smaller area fraction of acicular ferrite. No effect of the preheat/interpass temperature on the impact toughness was observed. The formation of a weld metal heat-affect zone showed little effect on the impact toughness of the weld metal in this experiment.
Dynamic Modeling of Autonomous Underwater Vehicle for Underwater Surveillance and Parameter Tuning with Experiments
Lee, Phil-Yeop ; Park, Sung-Kook ; Kwon, Soon Tae ; Park, Sangwoong ; Jung, Hunsang ; Park, Min-Soo ; Lee, Pan-Mook ;
Journal of Ocean Engineering and Technology, volume 29, issue 6, 2015, Pages 488~498
DOI : 10.5574/KSOE.2015.29.6.488
This paper presents the dynamic model of an AUV called HW200 for underwater surveillance. The mathematical model of HW200 is briefly introduced, considering its shape. The maneuvering coefficients were initially estimated using empirical formulas and a database of vehicles with similar shapes. A motion simulator, based on Simulink of Mathworks, was developed to evaluate the mathematical model of the vehicle and to tune the maneuvering coefficients. The parameters were finely tuned by comparing the experimental results and simulated responses generated with the simulator by applying the same control inputs as the experiment. The velocity of HW200 in the tuning process was fixed at a constant forward speed of 1.83 m/s. Simulations with variable speed commands were conducted, and the results showed good consistency in the motion response, attitude, and velocity of the vehicle, which were similar to those of the experiment even under the speed variation. This paper also discusses the feasibility of its application to a model-based integrated navigation system (INS) using the auxiliary information on the velocities generated by the model.