2020 Fiscal Year Final Research Report
Evaluation of effective stress around Mode II crack tips under rolling contact fatigue
Project/Area Number |
19K14875
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Research Category |
Grant-in-Aid for Early-Career Scientists
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Allocation Type | Multi-year Fund |
Review Section |
Basic Section 18040:Machine elements and tribology-related
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Research Institution | University of Toyama |
Principal Investigator |
Mizobe Koshiro 富山大学, 学術研究部工学系, 准教授 (70727718)
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Project Period (FY) |
2019-04-01 – 2021-03-31
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Keywords | 転がり疲労 / 介在物 / き裂 / 炉ー高周波併用加熱 |
Outline of Final Research Achievements |
In order to evaluate a driving force of the crack propagation under rolling contact fatigue using high-carbon high-chromium steels, we observed the fatigue cracks from non-metallic inclusions. We prepared the shaft which was furnace and induction quenched (FIH method) and performed one-point rolling contact fatigue. Through this FIH method, this specimen had a subsurface soft area of 0.5 mm from the surface. After the rolling contact fatigue tests, we found many fatigue cracks from the non-metallic inclusions. There were various lengths and depths of cracks and the cracks in the soft area were longer than those in other areas. This indicates that we successfully control crack initiation and propagation under rolling contact fatigue in FIH specimens.
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Free Research Field |
破壊力学、トライボロジー
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Academic Significance and Societal Importance of the Research Achievements |
風力発電機などに使用される大型軸受では、近年20年の実用寿命保証が求められており、軸受メーカーは超長期間、莫大な補償に備える事となってしまっている。このような超長期全数保証の根拠を確率的な現象に求めてしまっては、あまりに経済的な損失が大きい。本研究で得られた成果は破壊力学のき裂停留パラメータに注目したものであり、将来的に軸受の全数寿命保障に対する設計指針を確立することにつながる。
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