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Mechanisms of lubrication failure due to non-steady multi-scale surface structure and applied technology

非稳态多尺度表面结构润滑失效机理及应用技术

基本信息

批准号：
16360080
负责人：
SUGIMURA Joichi
金额：
$ 9.47万
依托单位：
KYUSHU UNIVERCITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

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.

本项目旨在通过关注表面粗糙度的非稳态和多尺度结构，探索混合润滑中润滑失效的机制，并从实验和理论上研究润滑膜的局部失效导致宏观润滑失效的过程。利用超薄膜干涉测量法对溅射纳米粗糙度表面和具有光刻产生的微凹坑的纹理表面进行了纯滑动点接触EHL实验。研究发现，磨损区域或微凹坑的通道会引起局部流体流动的变化，从而进一步导致磨损的萌生和扩大。此外，还设计并建造了一个新的测试室来研究环境气体对空洞形成的影响。在分析方面，引入离散小波变换来描述非稳态多尺度表面结构。 Haar函数被用作母小波。通过小波系数给出不规则排列的凹凸和凹坑，然后将其用作简单倾斜滑动轴承流体动力润滑数值分析中静止表面的微观形貌。另一项数值分析是对机械密封平平接触中纹理表面的流体动力润滑进行的，结果表明流体动力流体的流动对微坑的形状和位置的依赖性。为了研究润滑油膜中空腔的产生，求解纳维-斯托克斯方程，引入水平集法来寻找气液界面。确定了空腔的形状和位置，这取决于凹坑的形状和空化压力。