| Project/Area Number |
01850095
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Research Field |
船舶構造・建造
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| Research Institution | University of Osaka Prefecture |
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Principal Investigator |
OKADA Hiroo Univ. of Osaka Pref., Col. of Eng., Prof., 工学部, 教授 (90081398)
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| Co-Investigator(Kenkyū-buntansha) |
KITAURA Kenichi Univ. of Osaka, Research Associate, 工学部, 助手 (00081399)
KISHI Mitsuo Univ. of Osaka, Lecturer, 工学部, 講師 (00145814)
IKEDA Yoshiho Univ. of Osaka, Assoc. Prof., 工学部, 助教授 (10117989)
OKAMURA Yoichiro Univ. of Osaka, Assoc. Prof., 工学部, 助教授 (80081397)
MUROTSU Yoshisada Univ. of Osaka Pref., Col. of Eng., Prof., 工学部, 教授 (50081386)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1990: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥4,400,000 (Direct Cost: ¥4,400,000)
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| Keywords | Marine frame structure / Ultimate strength / Dynamical effect / Structural reliability / Dominant failure mode / Failure probability / Importance factor / Structural synthesis / 立体骨組モデル / 経年変化 |
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| Research Abstract |
1. At first, applicabilities of the program package developed for reliability assessment of marine structures are investigated through numerical examples for two typical semi-submersibles, which are modeled as spatial frames and subjected to quasi-static extreme loads based on ultimate strength analysis. Results obtained in this study are summarized as follows :
(1) The underlying theory and the system's overview are provided. (2) The applicability of the system is demonstrated through the numerical examples for structures under beam and oblique seas (3) Effects of some design alterations on system reliability are also discussed by introducing importance factors as reliability measures under a damaged condition.
2. Next, methods are presented for the probabilistic analysis on the ultimate strength and the natural frequencies of composite and slender offshore structures for deep water, which are treated as a simple tower model by replacing its tower frameworks and platform with the beam-columns with equivalent stiffness and strength, respectively. A method is also presented for reliability assessment of aged marine structures considering increase of extreme wave loads due to marine growth and corrosion, and deterioration of rigidity and resistance due to corrosion. Further, the effect of uncertainty on the natural frequencies is discussed by using a probabilistic sensitivity analysis method. Finally, the applicability of the proposed methods is demonstrated through the numerical example for a 450m guyed tower.
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