• Title/Summary/Keyword: LNG저장탱크

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Impact Properties and Fractography of Structural Materials for LNG Tank at Cryogenic Temperatures (LNG 저장탱크용 재료의 극저온 충격특성과 파면해석)

  • Shin Hyung-Seop;Lee Hae-Moo;Shin Ju-Yeong;Park Jong-Seo
    • Journal of the Korean Institute of Gas
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    • v.2 no.1
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    • pp.99-106
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    • 1998

  • In order to investigate the impact properties of structural materials for LNG tank, instrumented Charpy impact tests were carried out at cryogenic temperatures. $9\%$ Ni steel showed a superior fracture resistance because of less degradation in toughness until 77 K. From the load-deflection curve obtained by an instrumented methods it was found that with the decrease of temperature from 173 K to 77 K, the peak load in the curve increased, but the total absorbed energy decreased. In addition, the energy absorbed during the crack growth was larger than one absorbed in the process of crack initiation. In SUS304L material, the energy absorbed in the process of the crack initiation was relatively large, but the energy absorbed in the process of crack growth was small, the behavior of absorbed energy was well agreed with the observations of the fracture surface which showed a relatively smooth fracture surface. The absorbed Charpy impact energy in the case of A5083 alloy was lower as compared with other steels, and some cracks were observed along the crack propagation direction at the fracture surface of 77 K.

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Numerical Study on the Design Safety of Corner Protection Structure in Full Containment LNG Storage Tank (완전 밀폐식 LNG 저장탱크에서 코너 프로텍션 구조물의 설계 안전성에 관한 수치적 연구)

  • Kim Chung Kyun;Cho Seung Hyun
    • Journal of the Korean Institute of Gas
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    • v.8 no.2 s.23
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    • pp.54-60
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    • 2004

  • In this paper, the maximum von Mises stress and maximum displacement of the corner protection and secondary bottom structures have been analyzed using a finite element analysis technique. The design criterion of the comer protection is 1,500Pa for a normal nitrogen gas purging process at the beginning stage of start-up procedure. This pressure is very safe for the structure safety of the comer protection and secondary bottom plates. The corner protection and secondary bottom plates fabricated by $9\%$ nickel steel sheet may plastically be distorted and fractured for the increased gas pressure of 8,475Pa, which produces the maximum von Mises stress of 833MPa and maximum displacement of 1.9m at the center of secondary bottom plate.

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