Prediction of the slip zone friction coefficient in flat and rounded contact

Fretting fatigue (FF) experiments are usually carried out under a partial slip regime and tangential load control. This essentially means that the contact area is characterised by a central stick zone bordered by two slip regions. Evaluation of the coefficient of friction (COF) under such peculiar conditions is not an easy task. Furthermore, a variation of the COF with the number of fretting cycles has been already reported in previous studies. The current paper will extend the analyses already carried out for Hertzian contact to the flat-rounded geometry, recently used to simulate dovetail joints in turbine engine. The method presented enables prediction of the COF in the slip zones as a function of the measured mean value. The approach is completely general and may also be employed for other contact geometries.