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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 12, Issue 3 - Aug 1998
Volume 12, Issue 2 - May 1998
Volume 12, Issue 1 - Feb 1998
Volume 12, Issue 2 - 00 1998
Selecting the target year
Study on the Betterment of Construction Capacity in SHIELD Method
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 3~9
According to the developement of cities, electric wires and commuinication lines which are currently above the ground effect on the bad. Nowadays, it is necessary to build up underground facilities because the construction is increasing. Excavation work has been dominant even though the inconvenient things occurred, for example a civil appeal, a traffic obstacle, safety and spoiling the fine view because of the cost or period of the construction work. But the congestion of cities are more and more serious. Therefore shield-method is the way to escape from congestion. I considered all the construction fields which are in progress or finished.
Dynamic Explicit Elastic-Plastic Finite Element Analysis of Large Auto-body Panel Stamping Process
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 10~22
In the present work the elastic-plastic FE formulations using dynamic explicit time integration schemes are used for numerical analysis of a large auto-body panel stamping processes. For analyses of more complex cases with larger and more refined meshes, the explicit method is more time effective than implicit method, and has no convergency problem and has the robust nature of contact and friction algorithms while implicit method is widely used because of excellent accuracy and reliability. The elastic-plastic scheme is more reliable and rigorous while the rigid-plastic scheme require small computation time. In finite element simulation of auto-body panel stamping processes, the roobustness and stability of computation are important requirements since the computation time and convergency become major points of consideration besides the solution accuracy due to the complexity of geometry conditions. The performnce of the dynamic explicit algorithms are investigated by comparing the simulation results of formaing of complicate shaped autobody parts, such as a fuel tank and a rear hinge, with the experimental results. It has been shown that the proposed dynamic explicit elastic-plastic finite element method enables an effective computation for complicated auto-body panel stamping processes.
A Study on the Processing of Anti-Corrosive Composites for Propeller Shaft of the Ship and the Evaluation of Its Static and Fatigue Properties
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 23~31
Kind 1 propeller shaft in ships is the shaft which is provided with effective measures against corrosion by sea water, or the shaft which is made of approved corrosion resistance materials. The propeller shaft other than specified above is Kind 2. Thus, this study is mainly concerned with the resistance to fatigue damage in sea water against stress concentrations due to the notches. The results obtained can be summarized as follows; (1) The stress increases with curing time, however, when the curing time reaches at 96 hours the stress becomes a constant value. The elongation decreases with curing time, however, when the curing time reaches at 48 hours the elongation becomes a constant value. Thus, in case of FRP coating on propeller shaft, it is necessary to cure for 48 hours at least. (2) The relation of
is to be classified into two parts, which is a part where fracture nominal stress,
, decreases with increasing
, and a part where
is nearly constant independent of
. (3) According to a linear notch mechanics, the measure of severity controlling the fracture in notched FRP body is the notch root radius,
. The notched static strength of an arbitrary specimen will be estimated from
curve. (4) Through the observation of cross section after fatigue test, the part of interface was kept good condition irrespective of loading conditions.
Mechanical Characteristics and Fatigue Strength of Ceramic-Sprayed S45C Steel
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 32~38
This paper is to investigate of microhardness, adhesive strength, tensile strength, and fatigue strength of ceramic sprayed steel. Rotary bending fatigue tests have been conducted at room temperature in air and 3% NaCl solution using specimens of carbon steel(S45C) with sprayed coating layers of Ni-4.5% Al(under coating) and
(top coating). The microhardness has been improved at
heat treatment and 150mm spraying distance. Tensile strength of the sprayed steel is dependent on the substrate strength. The fatigue strength of the sprayed steel is larger than that of substrate due to blasting and constraint surface of plastic deformation effect. In low stress level, the corrosion fatigue strength of the sprayed steel were lower than that of fatigue strength in air by corrosion.
Fatigue Crack Growth Equation considered the Effect of Stress Ratio
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 39~49
In this work, fatigue tests by axial loading were carried out to investigate the effect of stress ratio on the growth behaviors of surface fatigue crack for SM45C steel and Al 2024-T4 alloy. The growth behaviors of surface crack have been monitored during fatigue process by measuring system attached CCTV and monitor. When the growth rates of surface crack were investigate by the concept of LEFM based on Newman-Raju's .DELTA.K, the dependence of stress ratio appears both SM45C steel and Al 2024-T4 alloy. Therefore, modified stress intensity factor range, .DELTA.K' [=(1+R)/sup n/.DELTA.K] are intorduced to eliminate the dependence of stress ratio. Using .DELTA.K', it is found that the dependence of stress ratio disappears both SM45C steel and Al 2024-T4 alloy.
A Model Estimating the Propagation Behavior of through cracks in Aluminum alloy A5083-O for LNG Tank
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 50~57
The leak before break(LBB) concept is generalized on the design of LNG tanks, pressure vessels and nuclear reactor in that any leakage of containment, in whatever amount, will not result in catastropic failure. For this purpose it is necessary to determine the surface crack shape, the opening displacement and the risk of catastropic brittle fracture when it becomes a through crack. In this study the crack propagation behavior of surface flaws and the crack opening displacement of through cracks under combined membrane and bending stresses were investigated with fatigue tests and fracture toughness test of aluminium alloy A5083-O. And fracture mechanics analysis of the crack opening displacement of through cracks were made in order to develop a new model expressing the behaviors of COD under combined membrane and bending stresses.
Reliability evaluation of brittle structures under thermal shocks
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 58~64
An analysis method for the reliability of ceramic structures subjected to thermal shocks is presented. Flaws with the size of given probability distribution function are assumed to be distributed at random with a certain density per unit volume in the structures. Criterions for crack instability are derived for brittle solids under general thermal stresses. A probabilistic failure model is presented to study the probability of crack instability for brittle solids containing cracks with uncertain size. The reliabilities of brittle structures are evaluated based on the weakest-link hypothesis, which states that a structure fails when the cracks in any differential volume become unstable. A numerical example is given to demonstrate the application of the proposed method.
J-R Curve Characterization by Load Ratio Analysis and Unloading Compliance Method for SA508 C-3 steel
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 65~75
The fracture resistance curve is one of most important and design techniques employed in nuclear pressure vessel structures. This study is to evaluate the J-R curve characteristics for the SA508C-3 by the unloading compliance method and load rato analysis. The effect of strain aging for the exponential correlation of the J-R curve in this metal are investigated at room temperature, 20
. The load ratio analysis method can evaluate the J-R curve by using the simple tension load-displacement curve only without the repeat of the unloading and loading. Therefore, the analysis by the proposed load ratio method has a merit, in comparison with the unloading compliance method, which can measure the crack length without the precision measurement equipment.
Life Prediction and AE Evaluation of Pure or Cyclic Creep for Power Plant Materials ; Pure Creep and AE Evaluation
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 76~84
In this 1st report, the relationship between pure creep properties and initial strain was studied and also its acoustic emission test was performed during creep test at 500, 600 and
. And the applicability of the acoustic emission technique was investigated to analyze the quantitive relationship between all the pure properties (creep strength, creep repture time or creep life, steady state creep rate, total creep rate, creep strain, total creep strain, etc.) and the initial strains as well as to analyze AE properties during the pure creep loading condition.
A Numerical Study of Nonlinear Free-surface Flows Generated by Motions of Two Dimensional Cylinders
Lee, Ho-Young ;
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 85~98
Open Boundary Modeling for Fully Nonlinear Wave Simulation in a 3-D Numerical Wave Tank
Boo, Sung-Youn ;
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 99~106
Estimation of Wave Power in Korean Coastal Waters
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 107~112
The purpose of this study is to analyze the amount of available wave power and its characteristics related to the development of apractical system for ocean wave energy conversion in Korean coastal waters. The analysis method of wave power was established through comparison between theory and numerical simulation of deep sea wave by Inverse Fourier Transform with random phase method. Based on the results of comparison, wave power was estimated by use of data set from observed offshore and coastal waves and hindasted deep sea waves around the Korean peninsula. Annual mean wave power is estimated as about 1.8 ~ 7.0 kW for every metre of wave frontage at East sea, 1.5~5.3 kW at South sea and 1.0 ~ 4.1 kW at West sea, respectively. Mean wave power along deep sea front of coastal waters of Korea amounts to about 4.7 GW. Regional distribution and seasonal variation of wave power were discussed to develop practical utilization system of wave power of not so high grade of available wave power.
PIV measurement of step cavity with driven flow
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 113~119
An experimental study was carried out in a three-dimensional cubic cavity driven by 2-dimensional plane Poiseuille flow for three kinds of Reynolds number,
based on the cavity width and cavity inlet mean flow velcoity. Instant simultaneous velocity vectors at whole field were measured by 2-D PIV system. Laser based illumination and two-frame grey-level cross correlation algorithm are adopted. Severe unsteady flow fluctuation within the cavity are remarkable at above Re = 3
Reynolds numbers and sheared mixing layer phenomena are also found at the region where inlet driving Poiseuille flow is collided with the clock-wise rotating main primary vortex at upper center area. Instant velocity profiles reveal that deformed forced vortex formation is observed throughout the separate two areas.
Application of Iterative Procedure to the wave Field with Energy Dissipation Area
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 120~127
An Elliptic model for calculating the combined refraction/diffraction of monochromatic linear waves is developed, including a term which allows for the dissipation of wave energy. Conjugate gradient method is employed as a solution technique. Wave height variations are calculated for localized circular and rectangular dissipation areas. It is shown that the numerical results agree very well with analytical solution in the case of circular damping region. The localized dissipation area creates a shadow region of low wave energy and the recovery of wave height by diffraction occurs very slowly with distance behind the damping region.
A Study on the Performance of Twin Hull Floating Breakwater
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 128~134
This study is carried out the theoretical studies on wave transmission and motions in waves of twin hull type floating breakwaters with the vertical and horizontal plate. The method of calculation is based on the three dimensional singularity distribution method. The results show that wave transmission is affected by heave motion. Twin hull type is designed by the use of the theoretical method and good performance of the developed floating breakwater is confirmed for longer wave period.
Ship Response Estimation Method in Multi-Directional Waves Using Real Sea Experiments
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 135~142
In this study, the frequency transfer function of motions are predicted from the result of a full-scale seakeeping trials. Because the real sea has the characteristics of multi-directional waves,we compare the results in the one directional waves with ones in the directional waves. For calculation of the frequency transfer function in the directional waves, Takezawa's inverse estimation method was introduced and the frequency ranges were divided into three parts in order to consider following seas. The full-scale seakeeping trials was executed in the south sea of Korea using the stern trawler. Those results show that analysis method of the multi-directional waves is more reliable than that of one directional waves, and confirm the possibility of applying this method to the full-scale seakeeping trials.
Liquefaction in Seabeds and Stability of Coastal Structure Foundations
Kang, Hong-Yoon ;
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 143~152
A Study on the Fluidity of Antiwashout Underwater Concrete Containing Fly Ash
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 153~161
This paper is to investigate the Fluidity of Antiwashout Underwater Concrete containing Fly Ash. The results of study are concluded as follows: the increase in Slump Flow value did not happen in the plain concrete which was replaced cement by Fly Ash; however, the maximum value could reach in the replacement of 30% of Fly Ash by weight of cement in the Fly Ash replaced concrete. On the condition of Fly Ash-Antiwashout Underwater Concrete in expecting 50 cm of the Slump Flow, it was necessary that the usage amount of Superplasticizer be around 1% of unit Binder, and 1.5% in 60 cm of the Slump Flow, respoectively.
A Study on the Development of Optimal System of Canal Barge System
Journal of Ocean Engineering and Technology, volume 12, issue 1, 1998, Pages 162~174
Construction of the Kyung-Inn Canal between Inchon and Han River water way of 18 kilometer length is considered recently. The canal may reduce traffic congestions between Seoul and Inchon, remarkably. Since the type of transportation system of the canal will be barge system, an analysis on the canal barge characteristics is carried out in this paper. The merits and demerits of various canal barge transportation systems are studied, respectively. Also, several barge connecting systems are studied and the corresponding characteristics are analyzed and compared. Optimal barge system is selected based on the simple modeling of the several barge systems and the relevant evaluations. Primitive design issue of the barge transportation system of the canal is also presented.