1993 Fiscal Year Final Research Report Summary
Reliability Analysis of Structures with Multiple Site Fatigue Cracks
| Project/Area Number |
04302034
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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 | YOKOHAMA NATIONAL UNIVERSITY |
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Principal Investigator |
ITAGAKI Hiroshi YOKOHAMA NATI.UNIV.PROFESSOR, 工学部, 教授 (10017882)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIZUKA Tetsuo YOKOHAMA NATI.UNIV.LECTURER, 工学部, 講師 (50017927)
FUJIMOTO Yukio UNIVERSITY OF HIROSHIMA PROFESSOR, 工学部, 教授 (60136140)
ISHIKAWA Hiroshi UNIVERSITY OF KAGAWA PROFESSOR, 経済学部, 教授 (60026200)
MIYATA Ryuji UNIVERSITY OF NAGOYA PROFESSOR, 工学部, 教授 (20023228)
SHIMIZU Akinobu YOKOHAMA NATI.UNIV.PROFESSOR, 工学部, 教授 (10015547)
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| Project Period (FY) |
1992 – 1993
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| Keywords | RELIABILITY / FATIGUE CRACK / MULTIPLE SITE CRACKS |
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| Research Abstract |
1. Reliability Analysis based on Non-Destructive Inspection of Structures with Multiple Site Fatigue cracks.
The influence of inevitable uncertain parameters on inspection planning was discussed. The uncertainties related to inspection planning can be classified into two categories : engineering uncertainty and economical/social uncertainty. Initial uncertainty can be gradually reduced by being updated through inspection results and/or service experience. The Baysian analysis is applied in conjunction with the sequential cost minimization method for a member set which has an uncertainty in the fatigue property of members.
2. Estimation of Distribution of Material Properties and its Effect on Fatigue Propagation Life.
A stochastic model for predicting fatigue crack growth was discussed by experimental approach. The model is based on the results of fatigue test using relatively large compact-tension-specimen under constant stress intensity factor range, (〕SY.upper filled triangle.〔) K, condition. The main results are : 1) There are large scale variation and small scale variation of material properties of fatigue crack growth. 2) It is very important to model the statistical correlation of material properties along crack path, particularly when the correlation length is large.
3. Selection of the First Inspection Time based Maximization of Amount of Information.
The first inspection time heavily infuences the overall structural reliability, and therfore several cost components as was noticed from pervious works. By optimizing an utility function, here simply regarded as mean Shannon information, a suitable criteria for selecting the first inspection time was discussed.
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