Nucleation of fatigue cracks at the notch tip

Notch tip fatigue and fracture behaviour is influenced by local plastic yielding, the extent of which is determined by the notch itself. In this paper, an assessment is made of the influence of the stress-strain gradient on nucleation of notch tip fatigue cracks. The results of a series of experiments performed with a range of theoretical notch factor K, values are compared with those calculated by applying the Coffin- Manson relation and Neuber's formula