Simple parameters to predict effect of surface damage on fretting fatigue

This paper presents two empirical parameters for the prediction of fretting. The first is a simple parameter, D fret 1, which is shown to correlate test data against fretting fatigue life in terms of the so-called running conditions of contact displacement and normal load. The second, more complex, parameter is shown to have the ability to capture: (i) the effect of relative slip on fretting fatigue life and (ii) a well-known fretting fatigue contact size effect in a more rational framework. This parameter combines a multiaxial fatigue parameter, the constants for which can be obtained from plain-fatigue testing, and a surface damage parameter D fret 2, which represents the surface damaging effect of fretting, the tribological constants for which can be obtained from fretting wear and fretting fatigue test data. A key benefit of D fret 2 is that it circumvents time-consuming incremental wear simulations.