Fretting fatigue life prediction for state-of-the-art materials and structures
Life of structural elements subject to fretting fatigue, tribofatigue and contact fatigue is predicted with innovative techniques developed by the author, colleagues from the Tribofatica Scientific Association (Belarus), and researchers of Western schools of fretting fatigue (Germany and Spain).

Fretting fatigue occurs at relative displacement (slip) of a cyclically loaded structural component and a clamped counterbody. Normal and shear surface stresses in slip give rise to early nucleation and quick propagation of short cracks with the stress intensity factors (SIF), being inversely proportional to the crack length, while SIF of normal is directly proportional to it. Fracture mechanics approach is widely used for prediction of fretting fatigue propagation phase, corresponding to the larger share of the structural component total life.

Mode (KI and KII) intial crack propagation, dependent on the friction coefficient, is controlled by different criteria, viz. the maximum tangential stress criteria by Otsuka, maximum normal stress criterion, etc. For structural components/counterbodies of different geometries, the combination of surface and bulk stresses controls the crack propagation direction and its rate, inducing recurrent variation of the total stress ratio R. This variation is accounted for via the Elber-Marci Keff concept modified by the author, while the effect of negative residual stresses, induced by shot- and laser peening, on SIF and total life is simulated.

Fretting fatigue life calculation results are presented for specimens and structural components from state-of-the-art aluminum and titanium alloys. Analysis of advanced fretting fatigue research outcomes confirms that this factor becomes critical for the in-service endurance of modern materials, and the fracture mechanics and tribological measurement-based calculation techniques provide a robust fretting fatigue life prediction, which may be extended to other domains of rigid body mechanics.