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Examination of Root Causes of Buckling in the Stern Structure of an Oil Tanker using Numerical Modeling

수치해석 모델링을 이용한 유조선 선미부 구조에 발생한 좌굴 발생 원인 검토

  • Myung-Su Yi (Department of Naval Architecture and Ocean Engineering, Chosun University) ;
  • Joo-Shin Park (Ship and Offshore Research Institutes, Samsung heavy industries)
  • 이명수 (조선대학교 선박해양공학과) ;
  • 박주신 (삼성중공업 조선해양연구소)
  • Received : 2022.11.04
  • Accepted : 2022.12.28
  • Published : 2022.12.31

Abstract

Recently, due to the specialization of structural design standards and evaluation methods, the classification rules are being integrated. A good example is the common international rules (CSR). However, detailed regulations are presented only for the cargo hold area where the longitudinal load is greatly applied, and no specific evaluation guidelines exist for the bow and stern structures. Structural design of the mentioned area is carried out depending on the design experience of the shipbuilder, and because no clear standard exists even in the classification, determining the root cause is difficult even if a structural damage problem occurs. In this study, an engineering-based solution was presented to identify the root cause of representative cases of buckling damage that occurs mainly in the stern. Buckling may occur at the panel wall owing to hull girder bending moment acting on the stern structure, and the plate thickness must be increased or vertical stiffeners must be added to increase the buckling rigidity. For structural strength verification based on finite element analysis modeling, reasonable solutions for load conditions, boundary conditions, modeling methods, and evaluation criteria were presented. This result is expected to be helpful in examining the structural strength of the stern part of similar carriers in the future.

최근, 구조설계 기준 및 평가방법의 전문화로 인하여, 선급 규칙의 통합화가 이뤄졌었다. 그 좋은 일례가 국제공통규칙(CSR, Common Structural Rule)이다. 그러나, 종강도 하중이 크게 작용하는 화물창 구역에만 국한하여 세부규정이 제시되어 있고, 선수와 선미부 구조에는 별다른 평가 지침이 없다. 언급한 구역의 구조설계는 조선사의 설계 경험에 의존하여 진행하고 있으며, 선급에서도 명확한 기준이 없으므로 구조 손상 문제가 발생하더라도 근본적인 원인을 파악하기가 힘들다. 본 연구에서는 선미부에 주로 발생하고 있는 좌굴 손상의 대표적인 사례에 대한 근본적인 원인을 파악하기 위한 엔지니어링 기반의 해법을 제시하였다. 유한요소해석 모델링 기반 구조 강도 검증을 위하여, 하중 조건, 경계조건, 모델링 방법 그리고 평가 기준에 대한 합리적인 해법을 제시하였다. 선미부에 작용하는 휨 모멘트에 의하여 높이 방향으로 압축하중에 의해서 좌굴이 발생할 가능성이 있으며, 좌굴 강성 증가를 위하여 판 두께 증가 혹은 수직 보강재의 추가가 필요하다. 앞으로도 이 결과는 유사 운반선의 선미부 구조 강도 검토 시 도움을 줄 것으로 기대된다.

Keywords

Acknowledgement

This research was supported by "Regional Innovation Strategy (RIS)" through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (2022RIS-002). This research was also supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (MOE) (NRF-2022R1I1A3068558)

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