The meaning of the local stress in fretting fatigue

It was previously shown experimentally that the effect of various factors influencing the fretting fatigue limit could be evaluated based on the local stress at the contact edge. In this report, the meaning of the local stress in fretting fatigue was studied. The crack analysis showed that the stress intensity factor change of a micro fretting fatigue crack was uniquely determined by the local stress irrespective of loading type and specimen size. Moreover, the fretting fatigue limit was the condition at which the micro crack remained as a non-propagating crack and this condition could be evaluated based on the concept of threshold condition of a short fatigue crack. It was concluded that the local stress can be a unifying parameter to evaluate the fretting fatigue limit.