1991 Fiscal Year Final Research Report Summary
Effects of Crack Damages on the Structural Response of Offshore Structures
| Project/Area Number |
02302052
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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 | Hiroshima University |
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Principal Investigator |
YAO Tetsuya Hiroshima Univ., Fac. of Engrg., Professor, 工学部, 教授 (20029284)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAGAWA Yoshio Hiroshima Univ., Fac. of Engrg., Research Associate, 工学部, 助手 (50229803)
FUJIKUBO Masahiko Hiroshima Univ., Fac. of Engrg., Assoc. Prof., 工学部, 助教授 (30156848)
FUJIMOTO Yukio Hiroshima Univ., Fac. of Engrg., Assoc. Prof., 工学部, 助教授 (60136140)
MURAKAWA Hidekazu Osaka Univ., Welding Research Inst., Assoc. Prof., 容接工学研究所, 助教授 (60166270)
TOYOSADA Masahiro Kyushu Univ., Fac. of Engrg., Professor, 工学部, 教授 (30188817)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Offshore Structure / Tubular Member / Crack Damage / Ductile Crack / CTOD / CTOA / Elastoplastic Analysis / Idealized Structural Unit |
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| Research Abstract |
1. A survey of the crack damages of offshore structures was made. It was shown that the crack damages were most likely to take place at the tubular joints and that the dented damages caused by collisions or object fallings acted as a crack initiator because of a large strain concentration at the bottom of the dent.
2. A series of pure tensile and pure bending tests of a tubular member having a circumferential through-thickness crack was carried out. The rigidity and load carrying capacity of the cracked tubular members were investigated considering the effects of ductile crack growth.
3. Based on the experimental results, the generation phase analysis was performed with the finite element method. It was found that CTOD and CTOA were the fracture parameters effective for the crack growth initiation and continuation, respectively.
4. The theoretical formula for the estimation of CTOD and CTOA were derived based on the semi-membrane shell theory and the assumption of Dugdale model.
5. The idealized structural unit method for a circumferentially through-thickness cracked tubular member was newly developed considering the ductile crack growth. A crack spring element was inserted between two intact beam-column elements in elastic analysis, while a plastic hinge was inserted in elastoplastic analysis based on the plastic node method.
6. Several numerical examples including a statically indeterminate portal frame with a crack damage showed the accurate and efficient capability of the proposed method.
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Research Products
(6 results)
