1987 Fiscal Year Final Research Report Summary
A Study on Structural Standardization of Connections of Floating Offshore Structure
| Project/Area Number |
60850081
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 Tokyo |
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Principal Investigator |
YOSHIDA Koichiro Faculty of Engineering, University of Tokyo, 工学部, 教授 (90010694)
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| Co-Investigator(Kenkyū-buntansha) |
小野木 宏 日本鋼管(株), 重工研究所, 構造研究室長
KOH Yunbo Faculty of Engineering, Nagasaki Institute of Applied Science, 工学部, 助教授 (70103398)
福岡 哲二 (株)三井造船昭島研究所, 主任研究員
TAMEHRO Masaki Faculty of Engineering, Hiroshima University, 工学部, 教授 (70155274)
ONOGI Hiroshi Heavy Engineering Institute, Nippon Kokan
FUKUOKA Tetsuji Mitsui Zosen Akishima Institute
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| Project Period (FY) |
1985 – 1987
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| Keywords | Semisubmersible / Structure of Connection / Internal Reinforcement / Transmission of load / Bukcling-Collapse Strength / Fatigue Strength / Model Test / 有限要素法 |
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| Research Abstract |
Based on results of survey of structural reinforcements at connections of actual semisub- mersibles, two cases were inverstigated in this study; a case wher a brace is directly welded to outer surface of column and a case where a brace penetrates a column shell wall.
On the other hand, based on results of analyses of actual semisubmersibles subjected to design waves, 12 kinds of foundamental load patterns were proposed to express loading conditions of connections by linear superposition of these foundamental load patterns. It was also confirmed that exial force applied to brace is dominant in structural strength of connection. Therefore, axial forces were mainly applied to braces in this study.
Tests using several Kinds of small scale acrylic models and calculations by the FEM were carried out in order to discuss transmission mechanism of load between internal reinforcement members of connection. It was clearified by thid study that such a case where a brace penetrates column shell wall and it is supported by a hrizontal diaghragm is the most effective from stress flow and weight minimizaing view points.
Buckling-collapse strength was studied by samll scale steel model tests and FEM calculations on specimens with differenct internal reinforcement members. It was concluded by these investi- gations that connections with brace penetration and internal supporting memberf of horizontal diaghragm or ring girder have relatively high resisntance to buckling-collapse. In the latter case, selection of face plate and appropriate allocation of tripping brackets for web platge of ring girder are important.
By using both small and large scale steel models, fatigue tests were carried out. It was clarified that the reinforcement method mentioned above showe high resistance to fatigue. Moreover, significance of crack initiation life, through-thickness life and failure life was discussed as a general aspect of the case of specimens with complicated reinforcement members.
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