2001 Fiscal Year Final Research Report Summary
Quantitative analysis fatigue fracture surfaces under Mode II and III and its application to tribology problems
| Project/Area Number |
11450047
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Kyushu University |
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Principal Investigator |
MURAKAMI Yukitaka Graduate school of Engineering, Kyushu University, Professor, 大学院・工学研究院, 教授 (10038010)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUSHIMA Yoshihiro Graduate school of Engineering, Kyushu University, Research Assistant, 大学院・工学研究院, 助手 (40156774)
SAKAE Chu Graduate school of Engineering, Kyushu University, Assistant Professor, 大学院・工学研究院, 助教授 (00253477)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Mode II fatigue crack growth / Very hard steel / Stress intensity factor / Mode II threshold stress intensity factor range / Tribology / Fractography / Friction / 【square root】area parameter model |
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| Research Abstract |
Mode II fatigue crack growth rate and Mode II threshold stress intensity factor range for the various materials were measured by using the newly developed testing system designed by head investigator.
The crack in spalling failure of steel making backup rolls : BUR propagates mostly in Mode II. The Mode II fatigue crack fracture surface morphology of the specimen was very similar to that of an actual BUR. The crack growth behavior of the fractured BUR was investigated based on fracture mechanics by using the laboratory test data of Δ K_<II^<th>> for the BUR. The analysis showed the guideline to prevent the spalling of the BUR in designing process.
The fatigue crack growth behavior under mode II and III loadings was studied on a 0.47 % carbon steel. Change in microstructure occurred at the crack tip in the process of crack growth both in mode II and III shear cracks. It is presumed that the crack growth mechanism of the mode II and that of the mode III are essentially the same.
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