Reliability prediction considering the stage of subcritical fatigue cracks growth

Fatigue failure is considered as a two-stage process that includes operating time up to the beginning of the surface damage and the stage of subcritical crack propagation. Taking into consideration of the second stage provides an opportunity to address a number of important practical problems, in particular: the definition of allowable defect size, the appointment of monitoring periods, evaluation of residual life, raising a reasoned normative terms of operation and more.