This paper presents an experimental study of the fretting crack nucleation
threshold, expressed in terms of loading conditions, with a cylinder/plane
contact. The studied material is a damage tolerant aluminium alloy widely used
in the aerospace application. Since in industrial problems, the surface quality
is often variable, the impact of a unidirectional roughness is investigated via
varying the roughness of the counter body in the fretting experiments. As
expected, experimental results show a large effect of the contact roughness on
the crack nucleation conditions. Rationalisation of the crack nucleation
boundary independently of the studied roughnesses was successfully obtained by
introducing the concept of effective contact area. This does show that the
fretting crack nucleation of the studied material can be efficiently described
by the local effective loadings inside the contact. Analytical prediction of
the crack nucleation is presented with the Smith-Watson-Topper (SWT) parameter
and size effect is also studied and discussed.Comment: 21 figure