The effect of fretting on fatigue

Continued fretting throughout the fatigue life of a component is inconsequential except that fretting surface debris may be continuously driven into the propagating cracks. This point to the belief that there exists some damage threshold for fretting fatigue, i.e., there may be some point in a component's fretting fatigue life where alleviation of further fretting may prevent premature fatigue failure. Conversely, if fretting occurs beyond some point in a component's fretting fatigue life, alleviation of further fretting may have no effect on the expected fretting fatigue life. This concept is illustrated by a combination of stress-life and crack growth curves.