Probability of Observable Flaw Initiation at High Cycle Fatigue

The question investigated in this contribution is how to describe and calculate the evolution of the probability of initiation of an observable fatigue flaw under a history of mechanical stimulus corresponding to fatigue at high number of cycles. It is proposed that this probability can be expressed as a simple and physically meaningful functional of the time history of entropy generated by an observation element during its fatigue history and of its elastic strain energy at fracture. A method based on simulation of a statistical population of microsystems is proposed for calculating the time history of entropy generation under certain assumptions shown to be reasonable in the case of high cycle fatigue.