Journal of the Society of Naval Architects of Korea (대한조선학회논문집)

The Society of Naval Architects of Korea (대한조선학회)
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Engineering Critical Assessement for an Independent Type-B LNG Cargo Tank

독립형 LNG 화물창의 공학적 결함 평가

  • Jae Hoon Seo (Department of Naval Architecture and Ocean Engineering, Inha University) ;
  • Kyu-Sik Park (Steel Solution R&D Center, POSCO) ;
  • Inhwan Cha (Hull Initial Design Department, Hyundai Mipo Dockyard Co., Ltd. (GRC)) ;
  • Joonmo Choung (Department of Naval Architecture and Ocean Engineering, Inha University)
  • 서재훈 (인하대학교 조선해양공학과) ;
  • 박규식 (포스코 철강솔루션연구소) ;
  • 차인환 ((주)현대미포조선 구조설계부) ;
  • 정준모 (인하대학교 조선해양공학과)
  • Received : 2023.02.15
  • Accepted : 2023.05.18
  • Published : 2023.08.20
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Abstract

The demand for Liquefied Natural Gas (LNG) carriers and LNG-fueled ships has significantly increased in recent years due to the sulfur-oxide emission regulations by the International Maritime Organization (IMO). The main goal of this paper is to introduce the process for the Engineering Critical Assessment (ECA) of IMO independent type-B cargo tanks made from 9% nickel alloy. A methodology proposed by the British Standard was used to conduct ECA for any structure with initial flaws. Based on this standard, a Matlab code was developed to perform ECA. Coarse mesh Finite Element Analysis (FEA) was performed on an independent type-B LNG cargo tank with a capacity of 15,000 m3. The location with the highest development of maximum principal stress was identified at the bottom of the cargo tank. Fine mesh FEA was performed to obtain the stress range required for ECA. The dynamic cargo tank loads used for FEA were determined using some ship rules presented by Det Norske Veritas. As a result of performing a 20-year long-term crack propagation analysis with a semi-elliptical surface crack, the fracture-to-yield ratio exceeded the Fracture Assessment Line (FAL) and some structural reinforcement was necessary. Performing a 15-day short-term crack propagation analysis, the fracture-to-yield ratio remained within the FAL, and no significant LNG leaks were expected. This paper is believed to provide a guide for performing ECA of LNG cargo tanks in the future by providing the basic theory and application sample necessary to perform ECA.

Keywords

Acknowledgement

본 결과물은 환경부의 재원으로 한국환경산업기술원의 플랜트연구사업의 지원(No. 146836) 및 해양수산부의 재원으로 해양수산과학기술진흥원(KIMST)의 지원(No. 202202103)을 받아 수행되었습니다.

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