• Title/Summary/Keyword: Keel

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Sensitivity analysis for seismic response of a ship-block system

  • Kuchaksarai, Masoud Moghaddasi;Bargi, Khosrow
    • Structural Engineering and Mechanics
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    • v.23 no.3
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    • pp.309-323
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    • 2006
  • In this paper, seismic response of a free-standing ship located in a dry dock and supported by an arrangement of n keel blocks due to base excitation is addressed. Formulation of the problem including derivation of governing equations in various modes of motion as well as transition conditions from one mode to another is given in Moghaddasi and Bargi (2006) by same authors. On the base of numerical solution for presented formulation, several numbers of analyses are conducted to study sensitivity of system's responses to some major contributing parameters. These parameters include friction coefficients between contacting surfaces, block dimensions, peak ground acceleration, and the magnitude of vertical ground acceleration. Finally, performance of a system with usual parameters normally encountered in design is investigated.

Resistance and stability evaluation of mobile fish-cage (이동형 수상부유식 가두리의 저항성능과 복원성능 평가)

  • KIM, Hyo-Ju;JEONG, Seong-Jae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.52 no.2
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    • pp.79-87
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    • 2016
  • Mobile fish-cage was developed assuming a cage net with an enclosed area, which and estimated the hydrodynamic characteristics of the cage through the model experiment. Flux-shielding plates, installed in the bow were compared with the resistance test carried out by making a hole, bilge keel and stud, and basic block flow rate consisting of the results to a flat surface plate. The experimental results confirmed the improved resistance performance effect of 3~6% in the bilge keel and the stud form. To assess the stability of the fish-cage, evaluation of the stability in accordance with the stability criteria for determining the floating docks had confirmed that it satisfied the static stability performance under operating conditions at sea.

On the prediction of global first-year ice loads (1년생 빙맥 하중 추정 모델)

  • Rim, Chae-Whan
    • Journal of Ocean Engineering and Technology
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    • v.11 no.3
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    • pp.144-152
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    • 1997
  • 본 논문에서는 1년생 빙맥에 의하여 해양구조물에 작용하는 하중을 추정할 수 있는 모델을 제시하였다. 1년생 빙맥을 수면하부(keel), 수면상부(sail), 경화층(consolidated layer)의 3부분으로 나누어 각 부분에 의한 하중을 추정할 수 있는 방법을 논의하였다. 수면하부는 얼음조각(ice rubble)이 층으로 쌓여져 형성된 것이므로 수면하부에 의한 하중추정을 할 때 얼음조각을 선형 Mohr-Coulomb재료로 생각하여 토질역학(soil mechanics)의 이론을 사용하였다. 수면상부에 의한 하중도 토질역학 이론을 이용하여 추정하였으며 경화층에 의한 하중은 Korzhavin식을 이용하여 추정하였다. 제시한 모델을 이용하여 빙맥하중 추정에 미치는 인자들의 영향을 검토하였다.

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A Study on the Hull Form of Fishing Boats around 1900 in South Coast of Korea (한국 남해안의 1900년경 어선의 선형에 관한 연구)

  • 고장권
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.36 no.3
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    • pp.244-248
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    • 2000
  • It was investigated and analized on the construction and hull form for the ordinary fishing boat of south coast in Korea, and then analogized on the shipbuilding technology of fishing boat and fishing type around 1900 by B-spline form parameter method. The results obtained can be summarize as follows : (1) It was known that the boats used in this study have more narrow hull form than that of ancient fishing boats and their hull form was improved around 1900. (2) Keel was composed of bar keel with angle cross section. The stem corner have a material of bar stem and makes a sharp pointed stem. (3) Shell plate was jointed by the rabbetted clinker joint method. (4) It was investigated that anchovy drag net fishing boat has high L/B, L/D, B/D value as compared with drift gill net fishing boat. (5) Two boats have a good stability and particularly anchovy drag net fishing boat have a better stability value in comparison to the drift gill net fishing boat.

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Design of Carbon Composite Prosthetic Feet using Finite Element Methods (유한요소 해석기법을 이용한 탄소복합소재 인공발의 설계)

  • Cho, Hyeon Seok;Cha, Gook Chan;Park, Jin Kook;Kim, Shin Ki;Lee, Suk Min;Mun, Mu Sung;Kim, Chang Bu
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.7
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    • pp.769-776
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    • 2013
  • The dynamic compliance characteristics of a prosthetic foot midgait are very important for natural performance in an amputee's gait and should be in a range that provides natural, stable walking. In this study, finite element analysis (FEA) and classical laminate theory were used to examine the mechanical characteristics of a carbon-epoxy composite laminate prosthetic foot as a function of variation in the lamination composition. From this analysis, an FEM model of a prosthetic keel, made from the composite material, was developed. The lamination composition of the keel was designed for improved stiffness. The prototype product was fabricated using an autoclave. Vertical loading response tests were performed to verify the simulation model. The results of the experiments were similar to those from simulations below the loading level of the gait, suggesting use of the proposed simulation model for prosthetic keel design.