Crack initiation

The rate of crack growth, and the resulting reduction in residual strength, from the time of crack initiation to a crack of critical length.

1) For an item subject to fatigue, the total time to failure, e.g. crack initiation. 2) For a human, fatigue is weariness, exhaustion, or decreased attention related to labor, exertion, or stress. May also result from lack of sleep, circadian shifts, depression, boredom, or disease. May result in decreased ability to perform mental or physical tasks.