Development of rheological measurement technique using fluorescence method and application for in-situ observation of lubrication film

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13677
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 18040:Machine elements and tribology-related
• Research Institution: Oita University
• Principal Investigator: Otsu Takefumi 大分大学, 理工学部, 准教授 (10634488)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: トライボロジー / 弾性流体潤滑 / レオロジー / 蛍光観察

Outline of Final Research Achievements

In this study, the rheological measurement system using fluorescence behavior of pyrene was proposed in order to understand the viscosity rising and the solidification of lubricant occurred in elasto-hydrodynamic lubrication film. It was revealed that the intensity ratio of pyrene excimer emission decreased with increasing viscosity, and that the intensity ratio was almost constant value under the condition for the solid state of lubricant. The relationship between viscosity and intensity ratio was obtained from fundamental results, and also the method for presuming the solidification was proposed. Moreover, the experimental results under the pure rolling condition showed that the viscosity increased at the inlet of contact, and that the state of lubricant changed to the solid in the contact area with high contact pressure. In addition, technical issues of this measuring method were discussed from the results obtained in this study.

Free Research Field

トライボロジー

Academic Significance and Societal Importance of the Research Achievements

本研究では当該分野で実現されていなかった油膜内のレオロジー測定技術を新規的に構築したものであり，これを潤滑面での観察・測定に応用することにより，接触面で起こる粘度変化や固体化といったレオロジー特性を詳細に理解することが可能となる．このような知見は潤滑現象を理解する上で重要な情報であり，潤滑メカニズムの解明の点で学術的に非常に意義のあるものと考える．また，本研究を基に潤滑理論の再検討を行う等，学術的な進展が期待でき，この結果は実用面での潤滑面設計の高度化にも繋がる．従って，機械要素の高精度化・高寿命化に寄与し，社会の安全・安心技術や省エネルギー技術に貢献できると考える．