Friction coefficient of UHMWPE during dry reciprocating sliding

Abstract

This paper deals with the friction coefficient behaviour during dry reciprocating sliding of UHMWPE in contact with alumina (Al2O3), within a range of velocities typical for hip implants. Five values of normal force (100 - 1000 mN) and three values of sliding speed (4 - 12 mm/s) have been observed. Real time diagrams of the friction coefficient as a function of the sliding cycles were recorded for each test. Dynamic friction coefficient curves exhibited rather uniform behavior for all test conditions. Somewhat larger values of friction coefficient could be observed during the running-in period in case of low loads (100-250 mN) and the lowest velocity (4 mm/s). In case of high loads and speeds, friction coefficient reached steady state values shortly after the beginning of the test.