Fretting fatigue – Experimental and numerical approaches

Current knowledge about the fretting phenomenon and multiaxial fatigue criteria is briefly reviewed. Experimental equipment for fretting fatigue testing at the Czech Technical University (CTU) in Prague is introduced, and the results of experiments are presented. The digital image correlation (DIC) method was employed to calibrate the friction coefficient in a numerical model. This detailed model of the fretting-fatigue experimental setup was then used for computing the stress field histories of periodically loaded specimens. This data was used as input for the multiaxial fatigue criteria, and the prediction quality of the criteria was verified. The prediction model assessment results are presented. The results indicate that the criteria are not capable of handling the different damage mechanisms, which vary with the pressure load of the contact interface. A certain correction reflecting the contact kinematic behaviour therefore needs to be introduced into their mathematical formulation. The DIC method performed well in capturing local displacements in the vicinity of the stick–slip interface, and it provided necessary data for calibrating the friction coefficient.