| Project/Area Number |
01850094
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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 | Osaka University |
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Principal Investigator |
UEDA Yukio Osaka University, Welding Research Institute, Professor, 溶接工学研究所, 教授 (30029037)
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| Co-Investigator(Kenkyū-buntansha) |
OKADA Hiroo Univ. of Osaka Prefecture, College of Engin., Professor, 工学部, 教授 (90081398)
TOYOSADA Masahiro Kyushu University, Faculty of Engineering, Professor, 工学部, 教授 (30188817)
YAO Tetsuya Hiroshima Universoty, Faculty of Engineering, Professor, 工学部, 教授 (20029284)
NAKACHO Keiji Osaka Univ., Welding Research Institute, Instructor, 溶接工学研究所, 助手 (10112070)
MURAKAWA Hidekazu Osaka Univ., Welding Research Institute, Assoc. Prof, 溶接工学研究所, 助教授 (60166270)
豊田 政男 大阪大学, 工学部, 教授 (00029191)
冨田 康光 大阪大学, 工学部, 教授 (30029251)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥11,300,000 (Direct Cost: ¥11,300,000)
Fiscal Year 1991: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1990: ¥5,300,000 (Direct Cost: ¥5,300,000)
Fiscal Year 1989: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Keywords | Design Permitting Buckling / Structural Reliability / Ultimate Strength / ISUM Rectangular Plate Element / Welding Deformation / Welding Residual Stress / Boxing Weld / Fatigue Strength / 高張力鋼 / 高品質軽量化船 / 座屈強度 / HT係数 / 理想化構造要素法 / 信頼性評価 |
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| Research Abstract |
Welding deformations and residual stresses in ship structures built using high tensile steel have been studied and methods to predicts these are proposed. The difference of tensile strength is found to have little influence on the inherent strain which is the cause of residual stress and it is shown that the residual stress can be predicted by a proposed method based on the inherent strain. When the steel is TMCP type, softening of the material along the welding is observed. The effect of such softening on buckling and ultimate strength is studied for cases with different welding position and boundary condition. Fatigue strength of various weld joints such as boxing weld is also an important problem. New reliable method to evaluate the fatigue strength is proposed.
For the full utilization of high tensile steel, it is effective to adopt a design concept which allows elastic buckling. The fatigue strengths of mild steel ship and high tensile steel ship are compared. Further, flowchart for structural design in which buckling is allowed is proposed. To evaluate the safety of a ship after damage, new efficient method based on the concept of plastic node is developed. It is shown that the computational time becomes 1/100 of that using conventional FEM. Using this method, the maximum bending strength of mid section of a ship is computed. In addition, a method to evaluate the reliability of a ship structure considering the statistical variation of external forces and dimensions of parts is proposed.
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