권호 표지

한국해양공학회지 (Journal of Ocean Engineering and Technology) (Journal of Ocean Engineering and Technology)

한국해양공학회 (Korean Society of Ocean Engineers)

  • 격월간
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  • 1225-0767(pISSN)
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  • 2287-6715(eISSN)

Aim & Scope

The “Journal of Ocean Engineering and Technology” (JOET) was launched in 1987 and is published bimonthly in February, April, June, August, October, and December each year by “The Korean Society of Ocean Engineers (KSOE).” Its ISO abbreviation is “J. Ocean Eng. Technol.” JOET publishes original research articles, technical articles, and review articles on all aspects of ocean engineering, including experimental, theoretical, numerical, and field observations. All manuscripts undergo peer-review by two or more reviewers. The scope of JOET encompasses the following research areas: - Ships and offshore engineering: Design of ships and offshore structures; Resistance and propulsion; Seakeeping and maneuvering; Experimental and computational fluid dynamics; Ocean wave mechanics; Fatigue strength; Plasticity; Optimization and reliability; Arctic technology and extreme mechanics; Noise, vibration, and acoustics; Concrete engineering; Thermodynamics and heat transfer; Hydraulics and pneumatics; Autonomous and unmanned ship; Greenship technology; Digital twin of ships and offshore structures; Marine materials - Coastal engineering: Coastal, port, and harbor structures; Waves transformation; Coastal and estuary hydrodynamics; Sediment transport and morphological change; Subsea geotechnics; Coastal groundwater management; Prevention or mitigation of coastal disaster; Coastal zone development and management; Shore protection technique; Coastal environmental process; Beach safety - Ocean energy engineering: Offshore wind turbines; Wave energy platforms; Tidal current energy platforms; Floating photovoltaic energy platform; Small modular reactor; Combined energy platforms - Marine robot engineering: Robot sensor system; Autonomous navigation; Robot equipment; Marine robot control; Environment mapping and exploration; Underwater communication and networking; Design of marine robots

https://www.joet.org KSCI KCI

제13권2호통권32호

  1. 정동원;양경부 1
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    This study is concerned with the application of new criterion for membrane/shell mixed element in the rigid-plastic finite element analysis and elastic-plastic finite element analysis. The membrane/shell mixed element can be selctively adapted to the pure stretching condition by using membrane or a shell element in the bending effect areas. Thus, membrane/shell mixed element requires a efficient criterion for a distinction between membrane and shell element. In the present study introduce the criterion using the angle of between two element and confirm a generality of criterion from appling the theory to a rigid-plastic and elastic-plastic problems.
  2. 정동원;이상제;김광희 11
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    The objective of this paper is to introduce very fast but still stable solution using finite element procedures, and it has been used in an iterative mode for product design applications. A lot of numerical techniques have been developed to deal with the material, geometric and boundary condition non-linearities occurred in the stamping process. One of them, the One-Step FEM is very efficient and useful tool for a design and trouble-shooting in various stamping processes. In this method, the mathod, the material is assumed to deform directly from the initial flat blank to the final configuration without any intermediate steps. The formulation is based on the deformation theory of plasticity and the upper bound theorem. As a result of the calculations, the initial blank shape is obtained, together with the material flow, strains and thickness distribution in the part.
  3. 김경수;손충열;신현일;이만식 18
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    Western coastal ports of Korea experience severe tidal range with up to 9.7 meter between high and low tides. The significant water level variation implicates many operational difficulties during loading and un-loading from cargo ships. To overcome problems due to tide and to secure the continuous loading operation, a new loading system for container cargo called "container pallet system" is developed and introduced in the paper. Three types of structure forms, offshore structural deck, double bottom structural form and the mixed form, are inverstigated with MSC/NASTRAN software. The results prove that the mixed type structure with truss enforcement is found to be the most appropriate for the region.
  4. 김경수;손충렬;김성준 26
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    Two types of barge, container and tanker vessels, are designed with specific dimensions for canal-coastal shipping in Kyung-In canal and Yellow Sea region. The principal dimensions of barges are determined by considering the environment of Kyung-In canal and Yellow Sea. The selection of structure type and structure type and strength confirmation is conducted by the technical rules of Korean Register of Shipping. For the structural analysis of designed barges, the semi-direct stuctural analysis is carried out with using MSC NASTRAN software. Applying identical dimensions to both vessels, the standardization of structural design and analysis procedure are introduced.
  5. 피재환;김윤해 35
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    Effects of CuO addition on the sintering ability and the phase stability of Y-TZP. (Yttria doped Tetragonal Zirconia Polycrystals) were studied. The CuO dopants were found to be quite effective in reducing the sintering temperature to obtain full density and refining the grain size. The maximum allowable concentration of the dopants was limited to 0.3%mol% for CuO to maintain fully tetragonal phase. With the addition of these dopants, the flexual strength decreased by 20% in comparison with the undoped specimen but the fracture toughness increased by 15%.
  6. 윤한기 41
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    As for the properties on both the aluminum and the CFRP which are used to make A17075/CFRP multi-layered hybrid composites, CRALL(carbon reinforced aluminum laminate). In the CRALL specimen for rule of mixture, we were analyzed notched strength by finite element method. The results obtained from FEM analysis are as follows; In the unnotch CRALL specimen, the stresses CFRP, epoxy, Al 7075 obtained by finite element method strength solution for A/C0001, when strain is 0.28%, are 1400MPa, 38MPa, 411MPa. respectively and for A/C9991, when strain 0.48%, are 392MPa, 26MPa and 321Mpa, respectively. the solpe of the stress-strain curve by FEM increases in keeping with the hole size and the yield strain decrease to 36% and 55% for A/C9993 and A/C9991 respectively.
  7. 강성원;이태훈;전재목;김충희 51
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    In this study, one side fillet welded T-joint, used in box type girder and other welding structure, was investigated by stress analysis and bending fatigue test without edge preparation, with variation of joint shape. The purpose of this study is to give the welding condiltion and design standard on manufacturing one side fillet welded T-joint. As a result, the following conclusions were obtained. 1) In one side fillet welded T-joint, the larger the leg length and the penetration depth, the greater the bending fatigue strength because reduction of stress and strain on toe and root. The increase of the longitudinal leg length rather than vertical leg length contributed to the increase in bending fatigue strength. 2) In one side fillet welded T-joint without edge preparation, both general manual welding and general automatic welding were carried out with same condition. In this case, automatic welding showed deeper penetration and more increased longitudinal leg length than manual welding, so that automatic welding offers greater bending fatigue strength. 3) For one side fillet welded T-joint without edge preparation with automatic welding, the ratio(h/t) of the leg length(h) and the main plate thickness(t) in which toe crake can occur was 1.0 over.
  8. 김선진;남기우;홍진표 58
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    The effect of specimen thickness on fatigue crack growth rate was studied. The objective of the present study is to investigate the effect of specimen thickness on the fatigue crack growth behavior at various stress intensity factor ranges and also the variation of material restance to fatigue crack growth. The fatigue crack growth resistance was treated as a spatial stochastic process, which varies randomly on the crack path, Compact tension specimens with a LT orientation for structural steel were used. All testing was done at a constant stress intensity level. The experimental data were analyzed for the size effect to determine the Weibull distributions of the material resistance.
  9. 공유식;오세규;이배섭 66
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    This paper presents the experimental examinations and statistical quantitative analysis of the correlation between the cumulative counts of acoustic emission(AE) during plastic deformation periods of the welding and the tensile strength and other properties of the tube-to-tube welded joints of O.D. 30mm (I.D 18mm) nozzle steel. This is a new approach which attempts finally to develop real-time quality monitoring system for friction welding. And this study results in practical possiblility of real-time quality control more than 100% joint efficiency showing good weld no micro structural defects.
  10. 오세규;양형태;김헌경 74
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    Nowadays, the crank shaft motor vehicle has become essential as the important component. The machining precision was asked for manufacturing the shaft. They could be unstable in the quality by the conventional are welding. Both in-process quailty control and high reliability of the weld are the major concerns in applying friction wlding to the economical and qualified mass-production. No reliable nondestructive monitoring method is avaliable at present to determine the real-time evaluation of automatic production quality control for bar-to-bar friction welding of the crank shaft of O.D 24mm for motor vehicle. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the cumulative counts of acoustic emission(AE) during plastic deformation periods of the welding and the tensile strength and other properties of the bar-to-bar welded joints of O.D. 24mm shaft as well as the various welding variables, as a new approach which attempts finally to develop real-time quality monitoring system for friction welding, resulting in practical possiblility of real-time quality control more than 100% joint efficiency showing good weld with no micro structural defects.
  11. 오세규;김일석;권상우;이학준 83
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    In this paper an experimental study on the development of the shielded metal are welding(SMAW) optimization technique for the dissimilar materials SS41 and STS304 of Auto-Lifting Magnet core plate was carried out. It was confirmed that the optimum welding heat input range was 37.5 to 45 kj/cm by considering on the strength and fatigue life of the welded joints more than 100% joint efficiency. And the quantitative relationship empirical wquation between the strength toughness adn fatigue life and the weld heat input was obtained.
  12. 정민화;이상국 90
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    Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep damage due to severe operationg conditions like high temperature and high pressure for an extended period time. Such material degradation lead to various component faliures causing serious accidents at the plant. Conventional measurement techniques such as replica method, electric resistance method, and hardness test method have such disadvantages as complex preparation and measurement procedures, too many control parameters, and therefore, low practicality and they were applied only to component surfaces with good accessibility. In this study, both artificial creep degradation test using life prediction formula and frequency analysis by ultrasonic tests for their preparing creep degraded specimens have been carried out for the purpose of nondestructive evaluation for creep damage which can occur in high-temperature pipelline of fossil power plant. As a result of ultrasonic tests for crept specimens, we confirmed that the high frequency side spectra decrease and central frequency components shift to low frequency bans, and bandwiths decrease as increasing creep damage in backwall echoes.
  13. 이상국;정민화 99
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    Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep damage due to severe operationg conditions which are high temperature and high pressure for an extended period time. Such material degradation leads to various component failures causing serious accidents at the plants. Conventional measurement techniques such as replica method, electric resistance method, and hardness test method have such disadvantages as complex preparation and measurement procedures, too many control parameters, and therefore, low practicality and they were applied only to component surfaces with good accessibility. In this paper, artificial creep degradation test and ultrasonic measurement for their creep degraded specimens have been carried out for the purpose of evaluation for creep damage which can occur in high-temperature pipeline of fossil power plant. Absolute measuring method of quantitative ultrasonic measurement for material degradation was established, and long term creep degradationtests using life prediction formula were carried out. As a result of ultrasonic tests for crept specimens, we confirmed that the sound velocity decreased and the attenuation coefficient linearly increased in proportion to the increase of creep fractiin(${\phi}$c).
  14. 이상호;한정섭 108
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    To study measurement of coated steel corrosion in mortar, a transient electro-magnetic(TEM) method was adapted. The sensors were made of enamelled wire with diameter of 0.25mm(transmitter), 0.1mm(receiver) and the secondary electro motive force(EMF) was measured with SIROTEMIII. The sensors configuration was used as in loop configuration. After coated steels were corroded by the salt spray during 3, 7, 15, 25days, they were embedded in mortar which were made from sand : cement : water ratio of 2 : 1 :0.5. To investigate coated steel corrosion in mortar, the sensors were used. ( sensorl - $T_x$ : $4{\Omega}$, $R_x$ : $10{\Omega}$, $3{times}3cm$, sensor2 - $T_x$ : $8{\Omega}$, $R_x$ : $10{\Omega}$, $3{times}3cm$, sensor3 - $T_x$ : $4{\Omega}$, $R_x$ : $10{\Omega}$, $6{times}6cm$, sensor4 - $T_x$ : $8{\Omega}$, $R_x$ : $10{\Omega}$, $6{times}6cm$). The obtained results showed that the secondary EMF was decreased with specimens of 3, 7days corroded coationg steel in mortar and then increased with specccimens of 15, 25days corroded one. And it was confirmed that measurement of coated steel corrosion in mortar by a transient electro-magnetic(TEM) method is possible.
  15. 윤종태 116
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    A deep water wave prediction model applicable to the East Sea is presnted. This model incorporates rediative transter of energy specrum, atmospheric input form the wind, nonlinear interaction, and energy dissipation by white capping. The propagation scheme by Gadd shows satisfactory results and the characteristics of the nonlinear interaction is simulated well by discrete interaction approximatiion. The application of the model to the sea around the Korean Peninsula shows reasonable agreement with the observation.
  16. 홍남호;김민찬;현명택 129
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    The time of the onset of double-diffusive convection in time-dependent, nonlinear concentration fields is investigated theoretically. The initially quiescent horizontal fluid layer with a uniform temperature gradient experiences a sudden concentration change from below, but its stable thermal stratification affects concentration effects in such way to invoke convective motion. The related stability analysis, including Soret effect, is conducted on the basis of the propagation theory. Under the linear stability theory the concentration penetration depth is used as a length scaling factor, and the similarity transform for the linearized perturbation equations. The newlly obtained stability equations are solved numerically. The resulting critical time to mark the onset of regular cells are obtained as a function of the thermal Rayleigh number, the solute Rayleigh number, and the Soret effect coefficient. For a certain value of the Soret effect coefficient, the stable thermal gradient promote double-diffusive convective motion.
  17. 곽영기 138
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    The viscous flow around a ship hull is calculated by the use of RANS(Reynolds-averaged Navier-Stokes) solver. Reynolds stresses are midelled by using the k-${epsilon}$ turbulence model and the law is applied near the body. Body fitted corrdinates are introduced for the treatment of the complex boundary of the ship hull form and the governing equations in the physical domain transformed into ones in the computational domain. The transformed equations are numerically solved by an employment of FVM(Finite Volume Method). SIMPLE(Semi-Implicit Pressure Linked Equation) method is adopted in the calculation of pressure and the solution of the sidcretized equation is obtained by the line-by-line method with the use of TDMA(Tri-Diagonal Matrix Algorithme). To assure the proprietty of this computing method, HSVA tanker and Dyne hull are calculated ar both model and ship scale Reynolds number. Their reaults of pressure distributions on fore and aft body, axial velocity contours and transverse velocity velocity vectors and viscous resistance coefficients are compared with other's experiments and calculations.
  18. 부성윤 147
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    Warm or waste water discharged from offshore-based facilities often causes environmental polution as it is transported to coastal area due to tidal actions. In this research a floating-type current control structure is introduced in order to reduce the pollutant spreading in the coastal area. Effectivenss of the structure is investigated through the numerical experiment which is based on a 3-D finite difference multi-level scheme. The warm-water spreading in the bay is reduced when the draft of the structure increases and its optimum draft is found to be between 0.25h and 0.65h, where h is the water depth. The proposed structure is also tested in the Gohyun Bay and it ts proven to be applied to controllling pollutant spreading if its draft is properly chosen.
  19. 송무효 159
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    For exisiting $K_0$-oedometer, the lateral wall of the ring is cut thinly to make space and by filling the space with space with water or mercuty to keep the balance to the lateral pressure of a specimen, the pressure of the fluid is checked for the pressure of the specimen. But the devices to keep the balance to the lateral pressure of a specimen are complicated, difficult to manufacture and expensive. As newly developed $K_0$-oedometer is equipped with the load cell which can resist higher pressute than the lateral pressure of the specimen, there is nearly no deformation due to the lateral pressure of the specimen. And the measuting is cheap and easy as there are fewer accessories.
  20. 이귀주;권규혁;이건철 168
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    In the present paper, a hull form for the turtle boat type incinerating vessel was developed based on the Finite source Distribution Method(FDM) and 1-$C_p$ method. In order to obtain proper hull form within the limited time and budget, a computer program OCL(Optimization of $C_p$ and LCB) was developed adn used. For the confirmation of the theoretical results by OCL, these theoretical results were compared with results of model test in the circulating water channel (CWC)in Chosun University.
  21. 한창봉;박제웅 176
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    Currently, large size shipyards have performed the generating of piece and the nesting using shipbuilding-oriented CAD program, which requires high skilled operator and costs a lot. So, medium and small size shipyards have pursued other way to obtain the generating and the nesting due to an economic and a technical problems. Therefore, this research is to develop a program for the generating of pieces with parametric macro method and a STRIP program for the nesting of pieces by PC.