Fatigue Crack Growth Evaluation of IMO Type B Spherical LNG Cargo Tank Considering the Effect of stress ratio and load history

다국어 초록 (Multilingual Abstract)

The crack propagation on a spherical IMO Type B LNG tank deployed on a 150K class LNG carrier is studied. IMO Type B tanks require a high level of safety . Therefore, analyses such as strength evaluation, fatigue analysis, fatigue crack propagation analysis, and LNG leak rate should be conducted to ensure safety. Various fatigue crack growth models were proposed for fatigue crack propagation analysis. The Forman model and the Walker model con- sider the stress ratio. Furthermore, the Huang model, and the Lee and Kim model consider the stress ratio and the ef- fects of overload and underload present in the past load history on crack propagation.
To examine the effects of stress ratio and load history for the fatigue crack propagation models, the crack growth of the LNG tank was evaluated by considering the stresses under full load and ballast load operating conditions, and three stress amplitude sequence cases.

참고문헌 (Reference)

1 김을년, "구형 LNG운반선의 탱크지지 구조인 스커트의 좌굴강도에 대한 연구" 대한조선학회 54 (54): 393-405, 2017

2 K. Walker, "The effect of stress ratio during crack propagation and fatigue for 2024-T3 and 7075-T6 aluminum" ASTM 1970

3 H. Tada, "The analysis of cracks handbook" ASME Press 2000

4 IMO, "The International Code of the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code)"

5 J. A. Newman, "The Effects of Load Ratio on Threshold Fatigue Crack Growth of Aluminum Alloys" Virginiatech 2000

6 E. D. Eason, "Technical basis for a revised fatigue crack growth rate reference curve for ferritic steels in air" 114 : 80-86, 1992

7 R. G. Forman, "Study of fatigue crack initiation from flaws using fracture mechanics theory" 4 : 333-345, 1972

8 X. Yan, "Prediction of fatigue crack growth in a ship detail under wave-induced loading" 113 : 246-254, 2016

9 D. S. Dawicke, "Overload and underload effects on the fatigue crack growth behavior of the 2024-T3 aluminum alloy" NASA 1997

10 A. J. McEvily, "On the threshold for fatigue-crack growth" 2 : 1293-1298, 1977

11 T. R. Porter, "Method of analysis and prediction for variable amplitude" 4 : 1972

12 N. E. Dowling, "Mechanical Behavior of Materials" Pearson 574-581, 2013

13 DNV GL, "Liquefied gas carriers with spherical tanks of type B"

14 X. P. Huang, "Improved modeling of the effect of R-ratio on crack growth rate" 29 : 591-602, 2007

15 "IIW-XIII-1235-87, A Review of Japanese Research into the Fatigue of A5083 Alloy Construction for LNG Spherical Tanks"

16 Y. Nagata, "IHI-SPB Tank for LNG-Fueled Ship" 2 : 2015

17 Hyundai Heavy Industries, "Hyundai Heavy Industries Quality Manual"

18 M. Toyosada, "Fatigue crack propagation for a through thickness crack: a crack propagation law considering cyclic plasticity near the crack tip" 26 : 983-992, 2004

19 R. I. Stephens, "Fatigue crack growth with negative stress ratio following single overloads in 2024-T3 and 7075-T6 aluminium alloys" ASTM 172-183, 1976

20 A. Chahardehi, "Fatigue crack growth under remote and local compression - a state-of- the-art review" 35 : 41-49, 2016

21 M. S. Lee, "Fatigue crack growth model considering underload history for storm loads" 2022

22 LR, "Fatigue assessment of ship units adopting IMO Type B independent tanks constructed primarily of plane surfaces for the storage of liquefied gases"

23 M. Kurihara, "Effects of stress ratio and step loading on fatigue crack propagation rate" 1 : 217-233, 1985

24 "BS8118, Structural use of aluminum"

25 "BS7910, Guide to methods for assessing the acceptability of flaws in metallic structures"

26 J. C. Newman Jr, "Analyses of surface cracks in finite plates under tension or bending loads" NASA 1979

27 X. P. Huang, "An engineering model of fatigue crack growth under variable" 30 : 2-10, 2008