MEASUREMENT OF FRICTION COEFFICIENT UNDER RECIPROCATING SLIDING CONDITIONS

The friction coefficient between two surfaces in Hertzian contact unde r reciprocating sliding motion has been determined as a function of lo ad and sliding speed. A gradient search technique that minimizes the l east square error between experimental and theoretical responses at th e resonant frequency of the system was used. Three of the most common engineering materials were tested. They are: Uns G10100 CD steel, 30% Zn brass, and aluminum (99.45% pure). The results indicate that the fr iction function decreases exponentially with sliding speed and the exp onential constant decreases [with load] as well. Moreover, the frictio n function decreases quadratically with load. The friction coefficient was found to have upper and lower limits that decrease with load incr ease, and which tend to approach the same value at relatively high loa ds.