A Statistical Analysis of Forces at a Sliding Interface

A statistical analysis has been made of the normal and tangential forces involved in friction and wear tests of two long range ordered (LRO) alloys. The analysis used descriptive statistics and a regression technique which provided a time varying friction coefficient M(t) in addition to M(a), a coefficient based on average force values. The normal and tangential forces responded differently. Part of the differences was due to the specimen mounting arrangement which damped and filtered the tangential more than the normal force. Another part was due to the film formation on the LRO alloy. One alloy did not form a stable and durable film; this alloy has a fairly constant M(a) and a zero M(t) value. The other alloy did form a stable film; this alloy had a M(a) which increased to a constant value during testing while M(t) was not zero. Thus the sensitivity and information content of a straightforward friction and wear test was considerably improved by a statistical analysis of the forces involved. Presented as...