Application of Preisach analysis to detection of fatigue damage

Measurements of hysteresis loops, initial magnetization curve and families of differential permeability curves were made on a series of 0.05 and 0.1 wt.% C Fe-C samples subjected to fatigue under load control. Preisach-like functions were calculated using the permeability data. Based on these functions a new parameter was identified which was found to decrease monotonically with increasing number of fatigue cycles whereas the classical magnetic hysteresis loop parameters remained constant. This result indicates that the method may be used as a nondestructive evaluation (NDE) technique for estimating expended fatigue life of ferromagnetic materials.