On the evaluation of fracture fatigue entropy

Fatigue is an irreversible degradation process wherein entropy increases until its accumulation reaches a critical failure value referred to as the fracture fatigue entropy (FFE). An experimentally-verified analytical approach for determining the entropy generation is presented that illustrates how the concept of FFE can be applied to analyze both low- and high-cycle fatigue. It is shown that the analysis should properly consider the contribution of internal friction, which does not contribute to the fatigue fracture. This parameter plays a significant role in high-cycle fatigue.