there are two analytical concepts that are very important in fatigue failure.the first one is crack closure and the others is residual stress .the first one is in behind of crack and the other emphasis in the front of crack tip. the question is if we use some devices such as AFM/SEM is it possible we model the energy filed during fatigue process?   if this idea can be investigated the second question can be asked: is there any similarity to model for different loading conditions? 

I appreciate if you also put your comment in my idea?

Bes Regards,

Hadi