| Project/Area Number |
03555095
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| Research Category |
Grant-in-Aid for Developmental 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 | KYUSHU UNIVERSITY |
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Principal Investigator |
TOYOSADA Masahiro KYUSHU UNIV.,FACULTY OF ENGN.,PROFESSOR, 工学部, 教授 (30188817)
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| Co-Investigator(Kenkyū-buntansha) |
MURAI Ryousuke MITUBISHI HEAVY INDUSTRY,HIROSHIMA INSTITUTE, 広島研究所, 研究員
KAJIMOTO Katuya MITUBISHI HEAVY INDUSTRY,HIROSHIMA INSTITUTE, 広島研究所, 主務
NIWA Toshio KYUSHU UNIV.,FACULTY OF ENGN.,RESEARCH ASSOCIATE, 工学部, 助手 (10208267)
小川原 陽一 九州大学, 工学部, 教授 (20214033)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥9,000,000 (Direct Cost: ¥9,000,000)
Fiscal Year 1992: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 1991: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | COD for a Surface Crack / Superposition of Elasto-Plastic COD / COD of a Crack in Sheet / T Tubular Joint / CTOD / 誘起曲げ応力 / き裂開口変位 / 弾塑性重ね合わせ法 / 全面降伏 / 偏心による誘起曲げ応力 |
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| Research Abstract |
We invested at first that elasto-plastic COD's for a single edge cracked sheet(SC), which is a cross section of a surface crack, subjected to tension(sigma_m) were given by some superposition of COD's for a center cracked sheet(CC) subjected to tension and COD's for a single edge cracked sheet subjected to bending stress(m*) by eccentricity. As a result, COD's for SC by sigma_m are obtained by superposition of COD's for CC subjected to tens ion which stress is sigma_m plus 0.75m* and COD's for SC subjected to m*. In above treatment,m*/sigma_m is a function of sigma_m/sigma_y(sigma_y:yield stress) and decreases as sigma_m increases to zero when gross yield occurs.
Then working tension stress and bending stress for a cross section of a surface crack are obtained by K value at the deepest point of a surface crack working tension and bending. By adapting a simplified beam theory, aperient yield stress for SC due to bending in case of combined tension and bending is introduced.
This estimating method of COD's is applied to a surface flaw in a crown part of T tubular joint of an offshore structure. Estimated COD's at a center of a surface are in good agreement with experimental ones. As a result, it becomes clear that CTOD defined by the displacement of R end of a notch tip is tend to give smaller value in case of high working stress than CTOD defined by Dugdale model and hinge model for 3 point bending CTOD testing .
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