| Project/Area Number |
60302053
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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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 | Kyushu University |
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Principal Investigator |
TSUJI Isamu Faculty of Engineering, Kyushu University, Professor, 工学部, 教授 (80037697)
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| Co-Investigator(Kenkyū-buntansha) |
TOYOSADA Masahiro Faculty of Engineering, Kyushu University, Associate Professor, 工学部, 助教授 (30188817)
SHIMIZU Shigetosi Faculty of Engineering, Yamaguchi University, Professor emeritus, 工学部, 元教授 (20038532)
NOMOTO Toshiharu Faculty of Engineering, Tokyo University, Professor, 工学部, 教授 (80011170)
FUKUCHI Nobuyoshi Faculty of Engineering, Kyushu University, Professor, 工学部, 教授 (80039677)
HIROWATARI Tomoyuki Faculty of Engineering, Hiroshima University, Professor, 工学部, 教授 (10144875)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 1986: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1985: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | thermo-mechanical controlled process steels for ship-hull structure / sensitivity of hot cracking of welded joints / thermal elasto-plastic analysis by B. E. M. / ship hull vibration / softening of welded joint / fatigue strength of welded joint / evaluation of toughness of surface notch / 船体振動解析 |
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| Research Abstract |
Concerning widespread use of newly developed thermo-mechanical controlled process steels for ship hull structures, some related problems with weld quality and strength of ship hull structures are investigated. Solidification cracking experiments for three kinds of this type of steels are conducted using the Trans-Varestraint test.
In order to estimate critical strain rate for temperature drop within the brittle temperature range, a thermal elasto-plastic analysis is performed based on the boundary element method. Calculated results of the critical strain rate at the center of weld metal in the first pass of butt-welded joints are well agreement with the experimental values and the growth mechanism of this sort of solidification cracking is elucidated in some degree. Effects of softening due to large heat input welding on the fatigue and bending strengths of the welded joints are also examined experimentally.
In connection with the brittle fracture of ship structures, an experimental method to evaluate crack-tip opening displacement of surface notches such as weld flaws is proposed. As a matter of interest along with the thinner shell structures due to enlarging use of the higher strength steels, analytical and experimental studies are made to prevent ship hull vibration as well as buckling and collapse failures of thin shell structures subjected to large deflection.
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