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A study of fatigue wear of the ultra-high molecular weight polythylene in terms of frictional heat

超高分子量聚乙烯摩擦热疲劳磨损研究

基本信息

批准号：
12650146
负责人：
IMADO Keiji
金额：
$ 1.92万
依托单位：
Oita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650146/
关键词：
artificial joint ultra-high molecular weight polyethylene frictional heat coefficient of friction contact temperature Young's modulus pressure distribution wear ペクレ数摩耗衝撃試験

项目摘要

Lubricant temperature of artificial joint increased up to 10^。C due to frictional heat according to the lubricant volume and contact pressure. Temperature increment of lubricant is strongly affected by the thermal properties of the moving part. About 90% of the frictional heat is transferred to the mating part of UHMWPE. The softening of UHMWPE was confirmed with an increment of temperature. The coefficient of friction decreased gradually with an increment of time or sliding distance to about a half of an initial value in a simple reciprocal sliding condition. It is sensitive to the loading conditions rather than temperature changes. The contact temperature between UHMWPE disk and the sapphire glass plate was measured by the infrared radiometric microscope. Lubricant temperature was measured simultaneously and compared with the contact temperature. Temperature rise up to 12^。C was observed in 30 minutes under a condition of the mean contact pressure P__-=12.7 MPa and sliding speed 50nm/s. There was a linear relation between contact temperature and lubricant temperature in the vicinity of the contact band. From this experimental study, it was clarified that an increment of contact temperature with time was about two times higher than that of lubricant temperature near the contact band. The behavior of contact temperature increment in this experimental condition could be explained by a mathematical model of a uniform band heat source model. The Young's modulus of UHMWPE was estimated as 0.4 GPa by using Hertzian contact theory through the measurement of real contact area. The coefficient of friction is strongly influenced by the contact pressure distribution. This finding could be used to improve the lubricating condition of the hip joints by changing the profile of the femoral head to make an optimum contact pressure distribution.

人工关节的润滑温度提高到10℃。C根据润滑剂的体积和接触压力产生摩擦热。运动部件的热物性对润滑剂的温升影响很大。约90%的摩擦热传递到UHMWPE的配合部位。随着温度的升高，UHMWPE的软化现象得到证实。在简单往复滑动条件下，摩擦系数随时间或滑动距离的增加而逐渐减小，约为初始值的一半。它对载荷条件而不是温度变化很敏感。用红外辐射显微镜测量了UHMWPE圆盘与蓝宝石玻璃板的接触温度。同时测量了润滑油温度，并与接触温度进行了比较。气温上升到12摄氏度。在平均接触压力P_-=12.7 Mpa、滑动速度50 nm/S的条件下，在30分钟内观察到C，接触带附近的接触温度与润滑剂温度呈线性关系。实验研究表明，接触温度随时间的增加约为接触带附近润滑剂温度的2倍。实验条件下的接触温升行为可以用均匀带状热源模型的数学模型来解释。通过测量实际接触面积，用赫兹接触理论估算了超高相对分子质量聚乙烯的杨氏模数为0.4 Gpa。摩擦系数受接触压力分布的影响很大。这一发现可以通过改变股骨头的外形来改善髋关节的润滑状况，以获得最佳的接触压力分布。