• Title/Summary/Keyword: LNG운반선 화물창

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Study on Hydroelastic Analysis of LNGC Cargo by Global-Local Analysis Technique (전역-국부 해석기법에 의한 LNG 운반선 화물창의 유탄성 해석에 관한 연구)

  • Park, Seong-Woo;Cho, Jin-Rae
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.1
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    • pp.83-92
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    • 2007
  • There are many numerical methods to solve large-scale fluid-structure interaction(FSI) problems. However, these methods require very fine mesh to achieve the reasonable numerical accuracy and stability due to the concentrated and volatile hydrodynamic pressure caused by the liquid sloshing. Consequently, the numerical analysis targeting for the long-period time response with the desired numerical accuracy Is very highly time-consuming. The aim of this paper is to suggest a new method to analyze the hydroelastic behavior of the LNGC containment by using the global-local numerical approach. The reliability of the presented method is firstly examined, and then its efficiency is demonstrated by presenting that the long-period local responses of the LNGC containment are obtained with relatively short CPU time.

The Study of 1-Way FSI for Strength Assessment of LNG Cargo Containment System (1-way FSI 기법에 의한 LNG 운반선 화물창의 강도평가에 관한 연구)

  • Lee, Sung-Je;Yang, Yong-Sik;Kim, Sung-Chan;Lee, Jang-Hyun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.527-530
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    • 2011
  • 전 세계적인 LNG 수요 증가에 따라 LNG 운반선의 대형화 및 극한 환경의 항로 선택이 불가피해지고 있다. 이러한 상황에서 LNG의 슬로싱 현상에 따른 화물창의 구조적 안정성 여부가 큰 이슈거리로 떠오르고 있다. 슬로싱 현상에 의한 구조 안전성을 평가하는 가장 이상적인 방법은 유체 영역과 탱크의 복합적인 상호 작용을 완벽하게 구현하는 것이다. 하지만 과도한 계산 시간과 결과의 정확성이 확보되지 못한 상황에서 LNG 운반선 화물창의 안전성 평가에 적용하기에는 문제가 있다. 많은 연구 단체에서는 불규칙적인 슬로싱 압력 신호를 삼각파 등의 형태로 이상화하여 구조해석에 적용하고 있지만 이 또한 유체의 압축성 및 비선형성을 고려하는데 한계를 드러내고 있다. 본 연구에서는 슬로싱 하중을 받는 구조의 안전성을 평가함에 있어 쌍방향(2-way) FSI(Fluid-Structure Interaction)의 과도한 해석 시간 및 수렴의 어려움을 보안하고 유체의 비선형성을 고려할 수 있는 단 방향(1-way) FSI 기법을 이용하는 절차를 제안하고자 한다.

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A Study on 8-Stage Loading Method of the Scaffolding Module for LNG Carriers (LNG 운반선 비계 모듈의 8단 탑재 방안 연구)

  • Shin, Sang-Hoon;Ko, Dae-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.11
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    • pp.78-85
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    • 2020
  • The scaffolding system, which is a construction workbench of the cargo containment for a membrane LNG carrier, is a large truss structure composed of various members. To shorten the installation period and process of the scaffolding system, it is effective to enlarge the mounting unit from the existing two stages to eight stages. Owing to the increase in lifting load according to the large size of the module, the stresses around the pin and hole will be increased significantly. In this study, a tensile strength test and contact stress analysis were performed to confirm the structural safety. The relatively large hole deformation was observed visually near the average load generated in the vertical pipe at the top through tensile strength tests. A contact stress calculation confirmed the stress distribution around the hole. The contact problem was dealt with in terms of the Herzian contact stress. The possibility of 8-stage loading was examined by comparing the yield strength and contact stresses of failure critical locations. As a result, the 8-stage loading method of the existing scaffolding material was inadequate, and a new loading method with proper safety is proposed.

A study on the mechanical performance of impregnated polymer foam in cargo leakage of LNG carrier (LNG운반선의 화물 누출 시 함침된 고분자 폼의 기계적 성능에 관한 연구)

  • Park, Gi-Beom;Kim, Tae-Wook;Kim, Seul-Kee;Lee, Jae-Myung
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.4
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    • pp.345-352
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    • 2017
  • In this study, the effect of cryogenic liquefied natural gas leakage and loading on liquefied natural gas cargo hold is investigated to observe the performance of the polymer foam material that comprises the cryogenic insulation of the cargo hold. The primary barriers of liquefied natural gas carrier that are in contact with the liquefied natural gas will leak if damage is accumulated, owing to fluid impact loads or liquefied natural gas loading / unloading over a long period. The leakage of the cryogenic fluid affects the interior of the polymer foam, which is a porous closed cell structure, and causes a change in behavior with respect to the working load. In this study, mechanical properties of polyisocyanurate foam specimen, which is a polymer material used as insulation, are evaluated. The performance of the specimens, owing to the cold brittleness and the impregnation effects of the cryogenic fluids, are quantitatively compared and analyzed.

A Study on Loading Method of Large Scaffolding Module for LNG Carriers Using TRIZ (TRIZ를 이용한 LNG 운반선 대형 비계 모듈의 탑재 방안 연구)

  • Park, Myeong-Chul;Shin, Sang-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.3
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    • pp.94-100
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    • 2021
  • To improve the productivity of cargo containment construction for a membrane LNG carrier, it is important to shorten the installation period and process of the scaffolding system, which is a construction workbench of a cargo containment for a membrane LNG carrier. As an effective method, opinions are being gathered to enlarge the lifting unit from the existing two stages to eight stages. On the other hand, the stresses around the pin and hole will increase significantly because of the increase in lifting load according to the large size of the module. The purpose of this study was to establish a new large module-lifting plan by introducing TRIZ to solve these problems. This study adopted a method to utilize 40 inventive principles, which is one of the various problem-solving tools of TRIZ. First, technical contradictions were derived, the engineering parameters were selected. Second, efficient inventive principles were selected to overcome the technical contradictions using a contradiction matrix. Finally, the general and specific solutions were derived through the selected inventive principle, and structural analysis confirmed that the stress generated in the structure was low. The utility of TRIZ was confirmed by the successful lifting of large modules using the established lifting method.