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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 14, Issue 4 - Nov 2000
Volume 14, Issue 3 - Aug 2000
Volume 14, Issue 2 - May 2000
Volume 14, Issue 1 - Feb 2000
Volume 3, Issue 1 - 00 2000
Selecting the target year
Prediction of Wave Energy Absorption Efficiency of a Flp-Harbour Device by a Hybrid Integral Equation
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 1~6
Wave energy absorption by a flap equipped with a harbor in a water of finite depth is studied. The wave potential is calculated by a hybrid integral equation consisting of Green integral equations associated with Rankine and Kelvin Green functions. The absorbed wave energy is calculated by both the near-field and far-field methods. The present methods can be used for the design of a flap-harbor wave energy absorber since the numerical results by the two methods are in good agreement.
Non-regressor Based Adaptive Tracking Control of an Underwater Vehicle-mounted Manipulator
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 7~12
This paper presents a non-regressor based adaptive control scheme for the trajectory tracking of underwater vehicle-mounted manipulator systems(UVMS). The adaptive control system includes a class of unmodeled effects is applied to the trajectory control of an UVMS. The only information required to implement this scheme ios the upper bound and lowe bound of the system parameter matrices the upper bound of unmodeled effects the number of joints the position and attitude of the vehicle and trajectory commands. The adaptive control law estimates control gains defined by the combinations of the bounded constants of system parameter matrices and of a filtered error equation. To evaluate the performance of the non-regressor based adaptive controller computer simulation was performed with a two-link planar robot model mounted on an underwater vehicle. The hydrodynamic effects acting on the manipulator are included. It is assumed that the vehicle's motion is slow and can be predicted with a proper compensator.
The Radiation Evaluation for Development of Solar System by Using Solar on the Sea
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 13~18
Recently due to the environmental pollution and the requirement for the substitute energy the interest for development of the solar energy system has been highly escalated It has been approved that the solar energy is a very useful on e because of purity and low cost. Some studies about the evaluation of solar radiation on the land has been carried out but few studies on the sea. This paper deals with a study on the evaluation of solar radiation on the sea. The experiments were carried out on the training vessel on the adjacent water of Korea Japan and China for twenty days. The distributions of solar radiation from the sea were changed into nonlinear in from according to the temperature. The solar radiation on the sea has a great influence on the velocity of wind as well as the temperature The distribuition of solar radiation has higher values on the track of the coastal sea than the open sea at same conditions.
Analysis Methods of Hydroelastic Responses for a Very Large Floating Structure
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 19~27
In this paper hydroelastic responses of a very large floating structure(VLFS) are studied theoretically. We have been developed the source and dipole distribution method and pressure distribution method to evaluate the hydrodynamic pressures. The problem of vertical structural responses due to waves are calculated by using finite element method(FEM) and modal expansion method of a free-free beam Hydroelastic responses of VLFS in waves are computed by four methods developed in this paper. As a result the theoretical results of motion responses show good agreements with experimental ones
Numerical Simulation of Structural Response in Bow Collision (1st Report)
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 28~35
In this paper a complicated structural behavior in collision and its effect of energy transmission to the collision bulkhead was examined through a methodology of the numerical simulation to obtain a ideal bow construction and a location of collision bulkhead against heat on collision. At present the bow structure is normally designed in consideration of its specific structural arrangement and internal and external loads in these areas such as hydrostatic and dynamic pressure wave impact and bottom slamming in accordance with the Classification rules and the specific location of collision bulkhead by SOLAS requirement. By these studies the behavior of the bow collapse due to collision was synthetically evaluated for the different size of tankers and its operational speed limits and by the results of these simulation it provides the optimal design concept for the bow construction to prevent the subsequent plastic deformation onto or near to the collision bulkhead boundary and to determine the rational location of collision bulkhead.
Analysis of Contra-Rotating Propellers in Setady Flow by a Vortex Lattice Method
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 36~43
In this paper a Vortex Lattice Method is used to predict the performances of a contra-Rotating Propeller. Greeley and Kerwin's(1982) wake model is adopted instead of the exact trailing vortex geometry. The interaction of the two propellers is treated by the sense that the induction of one propeller upon the other propeller is averaged in the circumferential direction . Two single propellers (DTRC 4119 & DTRC 4842) are chosen and compared with the experimental and other numerical results published. Then the computational results for three CRP's (4-0-4 CRP(DTRC 3686+DTRC 3687A) 4-0-5 CRP(DTRC 3686+DTRC 3849) & DTRC CRT(DTRC 5067+DTRC 5068) are compared with the experimental and numerical results published. The interaction of both propellers by the change of inflow velocity and circulation of each propeller is investigated.
The Effect of Coagulation for Dispersion Modelling of Spilled Oil
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 44~52
The dispersion of surface oil is generally described as a break-up of oil slick into small oil droplets. These small droplets are subjected to turbulence and vertical circulation so that it can be entrained into subsurface. Sometimes they tend to be submerged into sea bottom permanently. The diameter of oil droplets is a critical parameter to determine their behavioral characteristics under water surface. At the same time the variations of droplet stability depends on the weathering of it. That is why the weathered oil has different mechanism from the unweathered one. The variability of physical properties of oil including viscosity and density contribute to interfere with effective separation of oil and emulsion droplets in water. Also in the presence of interactions among the droplets there are coalescing or coagulating effects on the dispersion process of droplets.
Analysis of Hydroelastic Responses for Very Large Floating Structures with a Shallow Draft
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 53~59
A numerical method to predict responses of very large floating structures in wave is suggested using source-dipole distribution method. The deflection of the plate is calculated by the finite element method in terms of rigidity matrix of each node. The calculated results for a plate are compared with the experimental ones.
The Stream and Exhaust Gas Characteristics for Variation of Exhaust Gas Temperature of Marine Incinerator Ejector
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 60~64
An experimental study was performed to investigate the optimal ejector and operating condition of vessel incinerator. Exhaust gas temperature and secondary air which makes vacuum pressure at ejector throat regions were considered as an important factor. According to the measurement of pressure temperature and nitrogen oxides between non combustion and combustion we found the stream and exhaust gas characteristics of incinerator. This results can give us the exhaust gas temperature control system air pollutant reduction method and the optimum ejector design.
Effect of Microstructure on the Characteristics of Fatigue Crack Propagation of Super Duplex Stainless Steel
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 65~69
This study is to investigate the characteristics of fatigue crack propagation in rolled super duplex stainless steel that was changed austenite-ferrite volume fraction by heat treatment. It was used two kinds of specimen the rolling and the transverse directions δ-phase fraction affected sound velocity hardness and Young's modulus. Characteristics of fatigue crack propagation was affected by anisotropy and (δ+γ) phase volume fractions.
Finite Element Analysis of Elasto-Plastic Large Deformation considering the Isotropic Damage (the 1st Report) -Development of Elasto-Plastic Damage Constitutive Model-
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 70~75
In this paper a new constitutive model for ductile materials was proposed. This model can describe the material degradation due to the evolution of isotropic damage during elasto-platic deformation. The plastic flow rule was derived under the framework of thermodynamic approach of continuum damage mechanics(CDM) in which plastic strain hardening parameters and isotropic damage were taken as thermodynamic state variables. And the process to determine material constants for constitutive model using an experimental data was presented.
Finite Element Analysis of Elasto-Plastic Large Deformation considering the Isotropic Damage(the 2nd Report)
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 76~83
this paper was concentrated on the finite element formulation to solve boundary value problems by using the isotropic elasto-plastic damage constitutive model proposed previously(Noh, 2000) The plastic damage of ductile materials is generally accompanied by large plasticdeformation and strain. So nonlinearity problems induced by large deformation large rotation and large strain behaviors were dealt with using the nonlinear kinematics of elasto-plastic deformations based on the continuum mechanics. The elasto-plastic damage constitutive model was applied to the nonlinear finite element formulation process of Shin et al(1997) and an improved analysis model considering the all nonlinearities of structural behaviors is proposed. Finally to investigate the applicability and validity of the numerical model some numerial examples were considered.
A Study on Behavior of materials for Flexural member of Reduced-Scale Models
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 84~88
The main objectives of this study are to compare the obtained mechanical characteristics of reduced-scale model materials with those of the prototype and to provide the information on the best selection of materials. Manufacturing techniques on the micro-concrete and reduced reinforcement are introduced. The test results of these materials are shown to be satisfactory with regard to the similitude requirement. The simple beam tests were performed to verify similitude in the bond behavior between micro-concrete and reduced reinforcement. Those results also prove that these manufacturing and experimental techniques are useful and reliable for reduced-scale model tests.
A Study on the mechanical Characteristics of Kevlar Plain Weft Knitted Fabrics Reinforced Composites for Development of Intrusion Beam of Car Side Door Application
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 89~98
Using conventional textile techniques such as weaving braiding knitting and stitching it is possible to produce a wide range two and three dimensional fiber preforms, however so far only a limited attention has been given to knitted fabrics in composite industry. This is mainly due to the opinion that knitted fabric reinforced composites posses low mechanical properties owing to their looped fiber architecture. But it is possible to obtain desired mechanical properties by selecting proper knitted fabric structure, In this paper mechanical characteristics of kevlar plain weft knitted fabrics reinforced plastics(KFRP) are evaluated for th development of intrusion beam of car side door. Tensile bending impact properties of KFRP are measured experimentally and crush demands of Americal Federal Motor Vehicle Safety Standard No.214(FMVSS 214) compared with the bending load and displacement of KFRP by quasi-static test method. The applicability and limitation of bending load and displacement of KFRP according to specimen size has been discussed.
Effect of Specimen Size on Fatigue crack Growth Rate in Steels
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 99~105
This paper describes the effect of specimen size on fatigue crack growth rate for the offshore structural high-tensile-strength steel BS4360 and machine structural steel SM45C. The purpose of the present study is to investigate the effect of stress ratio aspect ratio specimen width and specimen thickness of the fatigue crack growth behavior. Compact tension specimens with a LT orientation for BS4360 and SM45C steels were used, All testing was done at constant stress intensity factor range controlled fatigue crack growth condition. The investigation demonstrates that the fatigue crack growth rate is increased with increasing stress ratio and specimen thickness and is decreased with increasing specimen width. The fatigue crack growth rate is unaffected by aspect ratio until a/W=0.50 but is increased by increasing spect ratio from a/W=0.55
A Study on the Influence of Al Alloy Sacrificial Anode Efficiency due to Marine Environmental Variation
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 106~111
Recently it was reported that the life of Al Sacrifical anode is being used in port piers has been significantly shortened compared with the original design life (e.g. average life shortened from 20 years to 13-15 year) Those factors involving these problems mentioned above were seemed to be a quality of anode material and diverse environmental factors such as pH flow rate temperature Dissolved oxygen Chemical oxygen demand and resistivity etcm In this study flow rate and contamination degree(pH) of sea water affecting to sacrificial anode life hve been investigated in terms of electrochemical characteristics of Al alloy sacrificial anode It was known that the lifetime of Al alloy anode was shortened not only by increasing of self-corrosion quantity by varying flow rate of sea water but also by increasing corrosion current density due to the potential difference increment between Al anode and steel structure cathode by varying contamination degree of sea water. Especially when anode current density is from 1mA/cm2 to 3mA/cm2 and flow rate of sea water is under 2m/s anode current efficiency is 90% above However flow rate is over 2m/s anode current efficiency fell down sharply due to erosion corrosion as well as galvanic corrosion.
A Study on the Preliminary Design of Hull Form considering Viscuous Resistance
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 112~116
To determine a preliminary hull form with a minimum viscous resistance this study considers the systematic variations of full form and calculations of the viscous resistance for varied hull forms. A preliminary hull form can be determined from a parametric study of viscous resistance.
A Study on the Hull Form Definition with Economy Evaluation at Preliminary Ship Design
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 117~120
In the Step of preliminary ship design a designer should decide a economic ship. The economic ship has the least building cost to a annual freight amount satisfying a given design condition That is RFR is minimum among alternatives.
A Study on the Automatic Fairing and Modeling System of Hull From
Journal of Ocean Engineering and Technology, volume 14, issue 2, 2000, Pages 121~127
In this paper a new technique of inverse fairing problem for ship hull is proposed. Recently Lu solved the inverse fairing problem for automobile's body that was made by one surface element. In this system however hull surface is constructed by Gregory's composite surface interpolation method. So reflection line at boundary position is used as a tool of solving inverse problem in surface fairing. But the results are not good. The new concepts of Normal vector line and Constrained reflection line are introduced as an alternative tool. Energy minimization method for Normal Vector Line curve net and the inverse method for Constrained Reflection Line by using optimization technique are examined And the final lines from this proposed surface fairing method shows good fairness.