| Project/Area Number |
59460127
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| Research Category |
Grant-in-Aid for General 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 | Osaka University |
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Principal Investigator |
UEDA Yukio Osaka University, Professor, 溶接工学研究所, 教授 (30029037)
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| Co-Investigator(Kenkyū-buntansha) |
MURAKAWA Hidekazu Osaka University, Research Instructor, 溶接工学研究所, 助手 (60166270)
金 裕哲 大阪大学, 溶接工学研究所, 助手 (20144529)
NAKACHO Keiji Osaka University, Research Instructor, 溶接工学研究所, 助手 (10112070)
YAO Tetsuya Hiroshima University, Associate Professor, 工学部, 助教授 (20029284)
FUNAKI Toshihiko Osaka University, Associate Professor, 工学部, 助教授 (90029174)
KIM You・Chul Osaka University, Research Instructor (00025909)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,400,000 (Direct Cost: ¥6,400,000)
Fiscal Year 1986: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1985: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1984: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Offshore structure / Jack-up rig / Pipe structure / Joint / Dent / Rigidity / Ultimate strength / 理想化構造要素法 |
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| Research Abstract |
Based on the Idealized Structural Unit Method, an ultimate strength analysis method was developed for the safety check of earthbound offshore structures. By this method the behaviors of the structures reaching ultimate strength under various loading conditions were investigated with consideration of the effects of local rigidity and strength.
The object structure was divided into such elements as (1) joint, (2) pipe between two adjacent joints and (3) substructures composed of joints and pipes.
T-joint consisting of cord and brace was assumed as the basic joint. Systematic theoretical and experimental studies were carried out on the rigidity and strength. As a result, simple estimating equations for the rigidity and ultimate strength were formulated.
With this information, a new idealized structural unit, tubular joint element, consisting of springs, rigid bars and beam element was developed for T, Y and K joints in order to efficiently treat the local rigidity and strength in the whole structure analysis.
Idealizing the elastic-plastic large deflection behavior of a pipe, an idealized pipe element was developed. Also, a similar element was developed for dented pipes.
Using the above three idealized structural units, ultimate strength analyses were conducted for the whole structure of a jack-up rig and a jacket rig. Obtained were the following conclusions. (1) When the whole structure undergoes shear collapse due to horizontal load, ultimate strength is attained by yielding of the joints or buckling of the braces under compression depending on relative strength between the joints and braces. (2) The joint rigidity greatly influences the whole structural rigidity and ultimate strength. In addition, performing analyses of ultimate strength of a jack-up rig under survival and punch-through conditions, the safety of the structures in these cases was checked.
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