| Project/Area Number |
02402038
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| Research Category |
Grant-in-Aid for General Scientific 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 Faculty of Engineering, Professor, 工学部, 教授 (10017882)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIZUKA Testuo Faculty, of Engineering, Research Associate, 工学部, 助手 (50017927)
MORISHITA Shin Faculty of Engineering, Associate Professor, 工学部, 助教授 (80166404)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1991: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Fatigue Crack / Random Process / Stress-Intensity-Controlled test / Reliability / Simulation / 亀裂伝播速度 / 確率分布 / 疲労寿命 |
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| Research Abstract |
This research proposes a method to estimate numerically the reliability of fatigue sensitive structures with respect to fatigue crack growth. A method is proposed to experimentally determine the probability distribution functions of material parameters of the Paris law, da/dN=C (DELTAK/K_0)^m, using stress-intensity -factor-controlled fatigue tests. The auto-correlation function of the resistance to fafigue crack growth, 1/C, is also estimated from the experimental data.
The results of two high tensile strength steels, (BS4360 and L36E). show that the distribution of the parameter, m, is approximately normal and that of 1/C is a 3-parameter Weibull. The merit of the proposed method is that only a small number of tests are required to estimate the probability distribution function of fatigue crack growth life. The probability distribution of the fatigue crack length after a given number of load cycles or the number of load cycles for a crack to reach a given length can be estimated by simulation of non- Gaussian random processes with these functions.
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