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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
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Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 26, Issue 6 - Dec 2012
Volume 26, Issue 5 - Oct 2012
Volume 26, Issue 4 - Aug 2012
Volume 26, Issue 3 - Jun 2012
Volume 26, Issue 2 - Apr 2012
Volume 26, Issue 1 - Feb 2012
Selecting the target year
Parametric Study of Offshore Pipeline Wall Thickness by DNV-OS-F101, 2010
Choi, Han-Suk ; Yu, Su-Young ; Kang, Dae-Hoon ; Kang, Hyo-Dong ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 1~7
DOI : 10.5574/KSOE.2012.26.2.001
DNV-OS-F101 includes the concept development, design, construction, operation,and abandonment of offshore pipeline systems. The main objective of this offshore standard (OS) is to ensure that pipeline systems are safe during the installation and operational period. The pipeline design philosophy also includes public safety and environmental protection. The mechanical wall thickness design of a pipeline shall follow the design objectives and safety philosophy. This new design code includes a very sophisticated design procedure to ensure a safe pipeline, public safety, and environmental protection. This paper presents the results of a parametric study for the wall thickness design of offshore pipelines. A design matrix was developed to cover the many design factors of pipeline integrity, public safety, and environmental protection. Sensitivity analyses of the various parameters were carried out to identify the impacts on offshore pipeline design.
Study on Freak Wave Characteristics and Approximation of Wave Spectrum in Uljin Sea Area
Ryu, Hwang-Jin ; Hong, Sa-Young ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 8~13
DOI : 10.5574/KSOE.2012.26.2.008
This paper investigates the statistical properties of waves in the sea area of Uljin, which is located in the East Sea area of Korea. The wave data were measured using AWAC (Acoustic Wave and Current Meter), which was installed at a 16-m water depth from November 2010 to March 2011. The wave data acquisition rate, Hmax, monthly mean Hs, Tz, Tp, and wave direction are summarized. The distributions of Hs and Tz were analyzed using the Hs-Tz scatter diagrams. The measurement wave data were analyzed to investigate freak wave characteristics. By comparing the wave spectrum using the measurement wave data with the wave spectrum obtained by varying the JONSWAP wave spectrum, it was possible to approximate the wave spectrum shape at the Uljin Sea area.
Prediction of Effect Zone for Marine Organisms Using Distance Attenuation Equations for Oceanic Noise
Ha, Jeong-Min ; Lee, Jong-Myeong ; Lee, Jeong-Hoon ; Gu, Dong-Sik ; Choi, Byeong-Keun ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 14~19
DOI : 10.5574/KSOE.2012.26.2.014
There are insufficient data to consider the effect zone for the marine life of coastal fisheries, because no standard has been defined for the sound level of marine life. In this study, equations for distance attenuation were used to determine the effect zone for oceanic noises. A reference noise level was divided into 4 parts to consider the characteristics of the fishes, and the effect zone of each reference noise level was determined. To increase the reliability of the effect scope, approximately 100 repetitions of blasting work split into several parts by the boring depth, the sound level of the source caused by an increase in weight, and the effect zone were calculated using the prediction equation. According to the prediction, the maximum distance of the effect zone was 4.92 km.
An Experimental Study of Cuttings Transport in Directional Slim Hole Drilling
Han, Sang-Mok ; Kim, Jeong-Hwan ; Hwang, Young-Kyu ; Woo, Nam-Sub ; Kim, Young-Ju ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 20~25
DOI : 10.5574/KSOE.2012.26.2.020
During drilling, the precipitation velocity of cuttings within an annulus depends on the density and configuration of the cuttings, and on the density, viscosity, and rheological characteristics of the drilling fluid. In directional drilling in particular, it is difficult to adjust and control the cuttings. In contrast to vertical drilling, it is very important to evaluate the flow characteristics of a drilling flow field. However, research on the transfer features of cuttings is inadequate. In this study, in order to identify transfer features of cuttings, an experiment was performed under wide-ranging conditions by constructing a slim hole annulus (
) device. In this experiment, the particle volume fraction were influenced by particle size, particle concentration within the flow, pipe rotation, flow volume, and inclination of the annulus. In addition, a mathematical formula for volumetric concentration was deduced and compared to the test results and behavior of cuttings under the other drilling condition was made to be predicted. Therefore, this study can provide meaningful data for vertical and horizontal drilling, and for directional drilling.
Modified S-N Curve Method to Estimate Fatigue life of Welded Joints
Yang, Park-Dal-Chi ; Kim, Mi-Kyeong ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 26~32
DOI : 10.5574/KSOE.2012.26.2.026
In this paper, the effects of irregular bead shapes on fatigue life were investigated. A modified S-N curve method was used to estimate the fatigue life, which considered the inherent multiaxiality caused by the geometrical feature produced by the welding process. The point method of the critical distance method was used to determine the fatigue effective stress. Three types of fillet joint models were tested in the fatigue experiments. For each model, real bead shapes were collected using a 3D laser scanner, and finite element analyses were performed. The results of the analyses with actual bead shapes were compared with those using an idealized bead shape model. The results of the present analytical methods showed good agreement with the experimental results.
Effects of Diffusible Hydrogen Content and Hardness on Cold Cracking in High Strength Weld Metal
Seo, Won-Chan ; Bang, Kook-Soo ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 33~38
DOI : 10.5574/KSOE.2012.26.2.033
The effects of the diffusible hydrogen content and hardness on the cold cracking in high strength weld metal were investigated. The diffusible hydrogen contents were influenced by welding parameters such as the voltage and contact tip-to-work distance (CTWD). The diffusible hydrogen content increased with an increase in voltage. However, it was decreased with an increase in CTWD. CTWD also influenced the weld metal hardness,especially when the wire used had a higher strength than the base metal. This showed that weld metal hardness had a more powerful effect on weld metal cold cracking than the diffusible hydrogen content in this experiment.
Development of Strength Prediction Model for Lightweight Soil Using Polynomial Regression Analysis
Lim, Byung-Gwon ; Kim, Yun-Tae ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 39~47
DOI : 10.5574/KSOE.2012.26.2.039
The objective of this study was to develop a strength prediction model using a polynomial regression analysis based on the experimental results obtained from ninety samples. As the results of a correlation analysis between various mixing factors and unconfined compressive strength using SPSS (statistical package for the social sciences), the governing factors in the strength of lightweight soil were found to be the crumb rubber content, bottom ash content,and water-cement ratio. After selecting the governing factors affecting the strength through the correlation analysis, a strength prediction model, which consisted of the selected governing factors, was developed using the polynomial regression analysis. The strengths calculated from the proposed model were similar to those resulting from laboratory tests (R2=87.5%). Therefore, the proposed model can be used to predict the strength of lightweight mixtures with various mixing ratios without time-consuming experimental tests.
Estimation of Dynamic Motions and Mooring Forces for Floating Type Offshore Platform Based on Hydrodynamic Analysis
Cha, Ju-Hwan ; Moon, Chang-Il ; Song, Chang-Yong ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 48~57
DOI : 10.5574/KSOE.2012.26.2.048
This paper deals with numerical analyses in the context of estimations of hydrodynamic motions and dynamic loads for a floating type offshore platform using some exclusive simulation code such as code for the simulation of a floating type of offshore crane based on multi-body dynamics, along with the commercial code AQWA. Verifications of numerical models are carried out by comparing the RAO results from the simulation code. In the verification analyses, hydrodynamic motions are examined in the frequency domain for the floating type offshore platform according to the mooring lines. Both the hydrodynamic motions and dynamic loads are estimated for floating type offshore platforms equipped with the catenary type and taut mooring lines. A review and comparison are carried out for the numerically estimated results. The structural safety of the connection parts in an offshore structure such as a floating type offshore platform is one of the most important design criteria in view of fatigue life. The dynamic loads in the connecting area between a floating type offshore platform and its mooring lines are estimated in detail according to variations in the mechanical properties of the mooring lines. The dynamic tension load on the mooring lines is also estimated.
Conceptual Design of Product & Asset Lifecycle Management System for Marine Structures During Middle of Life
Kim, Seung-Hyun ; Lee, Jang-Hyun ; Son, Gum-Jun ; Han, Eun-Jung ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 58~67
DOI : 10.5574/KSOE.2012.26.2.058
Recently, both the integration of product data during design and production and the effective management of information during full lifecycles have attracted attention from shipyards and ship owners as a result of recycling regulations and a desire for efficient operations. Generally, PLM (Product Lifecycle Management) supports a collaborative environment during the BOL (Beginning of Life) stage, while an ALM (Asset Lifecycle Management) system provides all of the information required to maintain, overhaul, and discard/recycle all or part of a vessel during the MOL (Middle of Life) and EOL (End of Life) stages. The main goal of this paper is to suggest the fundamental configuration of a PALM (Product Asset Lifecylce Management) system and a method that can be used to utilize a marine vessel's lifecycle information during the MOL, emphasizing the maintenance information during the middle of life. The authors also suggest a PALM system configuration in which lifecycle information can be collected by a PEID (Product Embedded Information Device) integrating a microcomputer, sensors, and wireless network communication. Through a prototype PALM system, the suggested features and PALM system configuration are implemented.
Effect of Multi-directional Random Waves on Characteristics of 3-D Wave Field around Permeable Submerged Breakwaters
Hur, Dong-Soo ; Lee, Woo-Dong ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 68~78
DOI : 10.5574/KSOE.2012.26.2.068
This study proposes an improved 3-D model that includes a new non-reflected wave generation system for oblique incident and multi-directional random waves, which enables us to estimate the effect of the various wave-types on 3-D wave fields in a coastal area with permeable submerged breakwaters. Then, using the numerical results,the three-dimensional wave field characteristics around permeable submerged breakwaters are examined in cases of oblique incident and multi-directional random waves. Especially, the wave height, mean surface elevation and mean flow around the submerged breakwaters are discussed in relation to the variation of incident wave condition.
Nonlinear Buckling Characteristics of Ring-stiffened Circular Cylinders under Uniform External Pressure
Ahn, Dang ; Kim, Soo-Young ; Shin, Sung-Chul ; Chung, Bo-Young ; Koo, Youn-Hoe ;
Journal of Ocean Engineering and Technology, volume 26, issue 2, 2012, Pages 79~84
DOI : 10.5574/KSOE.2012.26.2.079
This study aimed to analyze the nonlinear buckling of ring-stiffened circular cylinders under uniform external pressure, e.g. hydrostatic pressure, considering material nonlinearity and initial imperfection. In the present study, we analyzed the collapse pressure of pressure vessels using ANSYS Workbench, which is a framework of finite element methods. First, linear buckling analysis is performed to find collapse modes of the model. Second, scaling the first mode shape with small factor, geometric model is pre-deformed. And then, by analyzing the nonlinear buckling of the pre-deformed shape, the collapse pressure is estimated. To verify the validity of the analyses, we compared the results with Ross' experimental results. Finally, we applied it to ring-stiffened circular cylindrical shell of the pressure hull of a small submarine.