Fatigue Crack Initiation Detection and Crack Length Measurement Method with an Ion Sputtered Film
| Project/Area Number |
17560123
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Design engineering/Machine functional elements/Tribology
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| Research Institution | University of Miyazaki |
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Principal Investigator |
GANG Deng University of Miyazaki, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90237040)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANISHI Tsutomu University of Miyazaki, Faculty of Engineering, Professor, 工学部, 教授 (40038055)
MAEDA Kouji University of Miyazaki, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50219268)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Crack Initiation Detection / Crack Length Measurement / Ion Sputtered Film / Fatigue Strength / Crack Growth |
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| Research Abstract |
This research developed a simple and high precision method to measure the length of a fatigue crack and to detect the initiation of a fatigue crack using an extremely thin ion sputtered metal film based on that the electric resistance of the film changes with the increase of the crack.
The electric resistance of a cracked film was calculated by the electro-thermal FEM analysis for crack length measurement. Based on the FEM analysis results, the relationship between the electric resistance and crack length is expressed by a practical formula. Fatigue crack length measurements for acrylic and metal test specimens were performed on the three-point fatigue test equipment. Based on the good agreements between the measurement results by the ion sputtered film and that by the optical microscope, it is clarified that the crack length measurement method with an ion sputtered metal film has a very high precision. In addition that the measurement system is very simple, this method can be said to have a high practical usability.
The ion sputtered metal film was also used to detect the initiation of a fatigue crack. Three-point bending tests were performed, and the initiations of micro cracks of about 0.4mm length at the bottom of notch of the bending specimens were detected successfully, and it is also clarified that the crack initiation life takes 80-90% of the total fatigue life for acryl specimens.
For the purpose of the applications of these crack length measurement method and crack initiation detection method to a metal machine element, vacuum evaporation of silicon and glass method and coating of adhesive method were developed to make an insulating film, which make it possible to use the ion sputtered metal film or a metal surface.
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Report
(3 results)
Research Products
(6 results)
