Mechanisms of lubrication failure due to non-steady multi-scale surface structure and applied technology
| Project/Area Number |
16360080
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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 |
Design engineering/Machine functional elements/Tribology
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| Research Institution | KYUSHU UNIVERCITY |
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Principal Investigator |
SUGIMURA Joichi Kyushu University, Faculty of Engineering, Professor, 大学院工学研究院, 教授 (20187660)
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| Co-Investigator(Kenkyū-buntansha) |
TAKATA Yasuyuki Kyushu University, Faculty of Engineering, Professor, 大学院工学研究院, 教授 (70171444)
TANAKA Hiroyoshi Kyushu University, Faculty of Engineering, Research Associate, 大学院工学研究院, 助手 (80264076)
牧野 武朗 三菱重工業(株), 長崎研究所, 主席研究員
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2004: ¥11,300,000 (Direct Cost: ¥11,300,000)
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| Keywords | tribology / surface roughness / surface damage / hydrodynamics / stochastic model / トライポロジー / トライボロイジー / 混合潤滑 / ウェエーブレット変換 |
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| Research Abstract |
This project aims at exploring mechanisms of lubrication failure in mixed lubrication by focusing on non-steady and multi-scale structure of surface roughness, and studying both experimentally and theoretically processes in which local failure of lubricating films leads to macroscopic lubrication failure. Pure sliding point contact EHL experiments were made with ultra-thin film interferometry for sputtered nano-roughness surfaces and textured surfaces having micro-pits produced with photo etching. It was found that that passage of worn area or micro-pits caused changes in local fluid flow, which further led to initiation and expansion of wear. Also, a new test chamber was designed and built to study effects of environmental gas on formation of cavities. In the analytical side, the discrete wavelet transform was introduced in order to describe non-steady multi-scale surface structures. Haar function was employed as a mother wavelet. Irregular alignment of asperities and pits was given by wavelet coefficients, which was then used as microtopography of stationary surface in the numerical analysis of hydrodynamic lubrication of a simple inclined slider bearing. Another numerical analysis was made on hydrodynamic lubrication of textured surfaces in flat-flat contact of mechanical seals, which showed dependence of hydrodynamic fluid flow on shape and location of the micro-pits. In order to investigate generation of cavities in lubricant films, Navier-Stokes equations were solved whereby the Level Set Method was introduced to seek gas-liquid interface. Shape and location of cavities were determined, which were shown to depend on shape of pits and cavitation pressure.
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Report
(4 results)
Research Products
(2 results)
