On the New Design of Liquid Dome Chair in Membrane Type LNG Carrier

멤브레인형 LNG선박의 리퀴드 돔 체어 구조개발

  • Kim, Jeong-Hwan (Department of Naval Architecture and Ocean Engineering, College of Engineering, Inha University) ;
  • Kim, Yooil (Department of Naval Architecture and Ocean Engineering, College of Engineering, Inha University)
  • 김정환 (인하대학교 공과대학 조선해양공학과) ;
  • 김유일 (인하대학교 공과대학 조선해양공학과)
  • Received : 2017.04.10
  • Accepted : 2017.07.04
  • Published : 2017.10.20


A membrane type LNG cargo tank is equipped with a pump tower and a liquid dome for loading and unloading of LNG. However, the membrane running continuously on the tank wall to prevent leakage of LNG is interrupted by the liquid dome, hence care should be taken in the design of liquid dome and its substructures. In case of GTT NO96 membrane type cargo containment system, chair structure is arranged along the periphery of the liquid dome targeting to support the membrane which is exposed to the both hull girder and thermal load. This paper proposes a new and simple chair structure, which outperforms traditional design from productivity point of view maintaining same level of structural safety. Strength assessment on the new design was performed to guarantee the structural safety of the new design, which includes strength, fatigue and crack propagation analysis.



  1. British Standard Institution (BSI), 2005. Guide to methods for assessing the acceptability of flaws in metallic structures. BS7910. UK: BSI Standards Publication.
  2. Det Norske Veritas AS, 2014. Fatigue assessment of ships structures. DNV classification notes No. 30.7. Norway: DNV.
  3. DNVGL-OS-C102, 2015. Structural design of offshore ships. Norway: DNV.
  4. IMO, 2014. International code for the construction and equipment of ships carrying liquified gasses in bulk - IGC code. UK: IMO.
  5. Kang, B.J. Kim, Y. Ryu, C.H. Ki, H.G. Park, S.G. & Oh, Y.T., 2015. Flaw assessment on an offshore structure using engineering criticality analysis. Journal of the Society of Naval Architects of Korea, 52(6), pp.435-443.
  6. Lloyd Resister, 2008. Additional design procedures: Procedure for analysis of pump tower and pump tower base. UK: LR.