Go to the main menu
Skip to content
Go to bottom
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
Selecting the target year
Practical Application of Neural Networks for Prediction of Ship's Performance Factors
Kim, Hyun-Cheol ; Park, Hyoung-Gil ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 111~119
DOI : 10.5574/KSOE.2015.29.2.111
In the initial ship design stage, performance predictions are generally carried out before and after the hull form design. The former is based on the main dimensions and power information, and the latter is based on the geometry of the hull form and propeller. This paper deals with the practical application of neural networks for the prediction of a ship's performance factors before and after the hull form design. For this, the hull form parameters that affect the performance are studied, and an optimal neural network structure based on the SSMB database is constructed. By comparing the results predicted by neural networks and the model test results, we confirmed that neural networks can be applied to practically evaluate the performance in the initial ship design stage.
Hydraulic Cylinder Design of Lifting Pump Mounting and Structural Safety Estimation of Mounting using Multi-body Dynamics
Oh, Jae-Won ; Min, Cheon-Hong ; Lee, Chang-Ho ; Hong, Sup ; Kim, Hyung-Woo ; Yeu, Tae-Kyung ; Bae, Dae-Sung ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 120~127
DOI : 10.5574/KSOE.2015.29.2.120
When a deep-seabed lifting pump is kept this device has bending and deformation in the axis due to its long length(8m). These influences can be caused a breakdown. Therefore, a mounting must be developed to keep the lifting pump safe. This paper discusses the hydraulic cylinder design of the lifting pump and structural safety estimation of the mounting using SBD(simulation-based design). The multi-body dynamic simulation method is used, which has been used in the automotive, structural, ship building, and robotics industries. In this study, the position and diameter of the hydraulic cylinder were determined based on the results of the strokes and buckling loads for the design positions of the hydraulic cylinder. A structural dynamic model of the mounting system was constructed using the determined design values, and the structural safety was evaluated using this dynamic model. According to these results, this system has a sufficient safety factor to manufacture.
Axial Vibration Analysis of Umbilical Cable with Pilot Mining Robot using Sea Test Data
Min, Cheon-Hong ; Yeu, Tae-Kyeong ; Hong, Sup ; Kim, Hyung-Woo ; Choi, Jong-Su ; Yoon, Suk-Min ; Kim, Jin-Ho ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 128~134
DOI : 10.5574/KSOE.2015.29.2.128
Axial vibration analysis is very important for a deep-seabed mining system. In this study, an axial vibration analysis was carried out to estimate the natural frequencies and tensions of the umbilical cable using experimental data obtained from the first pre-pilot mining test. The axial vibrations of the umbilical cable with a pilot mining robot at the bottom end were analytically determined. The range of the added mass coefficients of the pilot mining robot is estimated by comparing the experimental and analytical data. The natural frequencies and maximum tensions are calculated using four estimated added mass coefficients.
Calculation of Load on Jacket Leg during Float-over Installation of Dual Topsides using Single Vessel
Bae, Dong-Yeol ; Lee, Seung-Jae ; Lee, Jaeyong ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 135~142
DOI : 10.5574/KSOE.2015.29.2.135
The float over method is the most preferred method for installing heavy topside onto a jacket platform. A very complex platform with multiple jacket structures on a specific field requires multiple installation procedures. This study validated the installation of two topsides using a single installation barge to reduce the operation and installation cost. The hydrodynamic properties of the installation barge during the installation of two topsides were calculated. The tension and fender forces during docking were investigated to show the validity of the proposed dual topside installation method. In conclusion, the operational safety of the proposed procedure was validated through the calculation of the motion of the installation vessel and loads on the jacket legs.
Experimental Study on Motion of FPSO and Characteristics of Mooring System according to Turret Position
Lee, Dong-Yeop ; Hong, Jang-Pyo ; Cho, Seok-Kyu ; Kim, Yoon-Ho ; Sung, Hong-Gun ; Seo, Jang-Hoon ; Kim, Dae-Woong ; Kim, Byung-Woo ; Seo, Yong-Seok ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 143~153
DOI : 10.5574/KSOE.2015.29.2.143
Comparative Study on Sloshing Impact Flows between PIV and CFD
Yang, Kyung-Kyu ; Kim, Jieung ; Kim, Sang-Yeob ; Kim, Yonghwan ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 154~162
DOI : 10.5574/KSOE.2015.29.2.154
In this study, experimental and numerical methods were applied to observe sloshing impact phenomena. A two-dimensional rectangular tank filled with water and air was considered with a specific excitation condition that induced a hydrodynamic impact without an air pocket at the top corner of the tank. High-speed cameras and a pressure measurement system were synchronized, and a particle image velocimetry (PIV) technique was applied to measure the velocity field and corresponding pressure. The experimental condition was implemented in a numerical computation to solve incompressible two-phase flows using a Cartesian-grid method. The discretized solution was obtained using the finite difference and constraint-interpolation-profile (CIP) methods, which adopt a fractional step scheme for coupling the pressure and velocity. The tangent of the hyperbola for interface capturing (THINC) scheme was used with the weighed line interface calculation (WLIC) method to capture the interface between the air and water. The calculated impact pressures and velocity fields were compared with experimental data, and the relationship between the local velocity and pressure was investigated based on the computational results.
Experimental Investigation of Wedge Slamming Impact
Di, Ren ; Ahn, Gang-Su ; Kwon, Sun-Hong ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 163~168
DOI : 10.5574/KSOE.2015.29.2.163
This paper presents the results of experimental work on the wedge slamming impact problem. An experiment was done with a wedge model. The deadrise angle of the wedge was
. The model was made in two parts: the outside part was made of a 5-mm-thick steel plate that could be assumed to be a rigid body, and the inside part was made of a thin SUS plate that could be assumed to be an elastic body. Thin SUS plate thicknesses of 2 mm and 3 mm were used to determine the effect of plate rigidity. The drop height was varied from 0.25 m to 1 m to determine the effect of a large deformation.
Experimental Study on Correction of Thermal Conductivity Obtained by Heat Flow Method using Commercial Guarded Hot Plate Method Apparatus
Lee, Jin-Sung ; Kim, Kyung-Su ; Kim, Yooil ; Woo, Suck-Min ; Yun, Seungjin ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 169~174
DOI : 10.5574/KSOE.2015.29.2.169
This paper addresses experimental methodologies to measure the temperature-dependent thermal conductivity of the insulation materials popularly used for LNG cargo containment systems. The measurement techniques considered in this paper are the guarded hot plate (GHP) method and heat flow method (HFM). The former is based on the power supplied to the hot plate to keep the temperature constant, and the latter is based on a direct heat flux measurement. In order to improve the accuracy of the HFM, the thermal conductivity obtained by GHP was cross-compared with the HFM results, and a calibration factor was derived. It was found that the thermal conductivities measured by the two methods corresponded well under room temperature, but the deviation tended to slightly increase as the temperature decreased. Because of the easy installation and operability of HFM, it can be used to measure thermal conductivity in a large scale mock-up test or unit insulation panel test, where the GHP method is difficult to apply.
Comparison of Analysis Methods for Designed Spudcan Bearing Capacity and Penetration Behavior for Southwest Sea Soil
Jin, Haibin ; Jang, Beom-Seon ; Choi, Jun-Hwan ; Zhao, Jun ; Kang, Sung-Wook ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 175~185
DOI : 10.5574/KSOE.2015.29.2.175
Jack-up type WTIV(Wind Turbine Installation Vessel) is used to avoid the effects of waves when installing wind turbines in the Southwest Sea of South Korea. During the preloading procedure, unexpected penetration may cause some risks such as excessive penetration or punch-through failure. To ensure the safety of the WTIV during preloading, the bearing capacities should be evaluated based on the soil data at each borehole. Eight boreholes (OW-1 to -8) have been drilled in the Southwest Sea of South Korea. The bearing capacities of a spudcan designed to be used in this district are calculated using both a conventional analysis and finite element analysis with the soil properties of OW-1 to -8. A finite element analysis is carried out for OW-1, -3, and -4 to gain an in-depth understanding of the soil behavior during the penetration. OW-1, -3, and -4 are representative boreholes for a strong layer overlying a soft layer, a general soft layer, and a soft layer overlying a strong layer, respectively. The resultant bearing capacity curves versus the depth of the numerical analysis are compared with the conventional method. The results show that the conventional analysis is conservative. Case studies for different spudcan areas and shapes are also conducted to seek an appropriate spudcan type for the Southwest Sea of South Korea. Finally, a spudcan with a rectangular shape and a bearing area of
Nanoparticle Size Effect on Mechanical Properties of Carbon Fiber-reinforced Polymer Composites
Moon, Chang-Kwon ; Kim, Bu-Ahn ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 186~190
DOI : 10.5574/KSOE.2015.29.2.186
nanoparticles can be used to improve the performance of carbon fiber-reinforced epoxy resin composites. In this study, the effect of the size of
nanoparticles on the mechanical properties of carbon fiber-reinforced epoxy resin composites was investigated. The size of the
nanoparticles was easily controlled using heat treatment. The size of the
nanoparticles for this study were20nm, 100nm, and 200nm. Three types of carbon fibers with different diameters were also used in this study. The carbon fiber-reinforced epoxy resin composites with 20-nm
powder showed the highest tensile strength compared to the other types of CFRP, regardless of the fiber maker or fiber diameter. The size of the
powder and the diameter of the carbon fiber strongly affected the interfacial properties of all kinds of CFRP in this study.
Model Test of Dual-Buoy Wave Energy Converter using Multi-resonance
Kim, Jeong-Rok ; Hyeon, Jong-Wu ; Koh, Hyeok-Jun ; Kweon, Hyuck-Min ; Cho, Il-Hyoung ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 191~198
DOI : 10.5574/KSOE.2015.29.2.191
In this study, we proposed a new type of dual-buoy wave energy converter (WEC) exploiting multi-resonance and analyzed the experimental results from a model test in a 2-D wave flume. A dual-buoy WEC using multi-resonance has two advantages: high efficiency at the resonant frequencies and the potential to extend the frequency range available to extract wave power from the WEC. The suggested WEC was composed of an outer buoy and an inner buoy sliding vertically inside the outer buoy. As the power take-off device, a linear electric generator (LEG) consisting of permanent magnets and coils fixed at each buoy was adopted. Electricity was produced by the relative heave motion between the two buoys. To search for the optimal shape of a dual-buoy WEC, we conducted experiments on the heave motion of a two-body system in regular waves without an LEG installed. Model tests with six combinations of experimental models were conducted in order to find the motion characteristics of a dual-buoy WEC. It was found that model 2, which included a ring-shaped appendage to move the resonant frequency of the outer buoy toward a high value, showed a higher relative heave response amplitude operator (RAO) curve than model 1. In addition, the double-peak shape of the heave RAO curve shown for model 2 indicated the extension of the frequency range for extracting wave power in irregular waves.
Eddy Current Sensor Development for Offshore Pipeline NDT Inspection
Lee, Seul-Gi ; Song, Sung-Jin ;
Journal of Ocean Engineering and Technology, volume 29, issue 2, 2015, Pages 199~206
DOI : 10.5574/KSOE.2015.29.2.199
Regular high-strength carbon steel is currently the most commonly used pipe material for onshore and offshore pipelines. The corrosion of offshore pipelines is a major problem as they age. The collapse of these structures as a result of corrosion may have a heavy cost is lives and assets. Therefore, their monitoring and screening is a high priority for maintenance, which may ensure the integrity and safety of a structure. Monitoring risers and subsea pipelines effectively can be accomplished using eddy current inspection to detect the average remaining wall thickness of corroded low-alloy carbon steel pipelines through corrosion scaling, paint, coating, and concrete. A test specimen for simulating the offshore pipeline is prepared as a standard specimen for an analysis and experiment with differential bobbin eddy current sensors. Using encircling coils, the signals for the defect in the simulated specimen are analyzed and evaluated in experiments. Differential bobbin eddy current sensors can diagnose the defects in a specimen, and experiments have been carried out using the developed bobbin eddy current sensor. As a result, the most optimum coil parameters were selected for designing differential bobbin eddy current sensors.