Effect of ellipse motion paths with different aspect ratios on friction and wear of highly crosslinked polyethylene

Abstract

Cobalt chromium molybdenum alloy and highly cross-linked polyethylene are selected as the counterpairs in this study to carry out friction and wear testing over different ellipse motion paths to explore the influence of ellipse motion path on friction and wear of prosthesis materials. Here, the analytical methods for the periodic friction coefficient and special point wear are proposed to investigate the relationship between motion paths and tribological properties. The damage mechanism model of high cross-linked polyethyleneunder ellipse motion paths was established, which revealed the connection among material composition, motion paths and friction and wear mechanism. The results show that the friction coefficient and wear morphology are directly affected by changes in motion paths. The friction coefficient decreases with increasing aspect ratios, and the wear profile depth increases with increasing aspect ratios. The spatially resolved friction coefficient curve distinctly exhibits periodic “W”-type variation in elliptical motion paths. The friction coefficient shows maximum values at the long-axis endpoints and minimum values at the short-axis endpoints. There are different wear morphologies in different characteristic areas over the elliptical wear paths. The wear profile depth and width at the long-axis endpoints are larger than those at the short-axis endpoints, and the wear morphology is also more serious.