A unified treatment of the mode I fatigue limit of components containing notches or defects

The paper addresses the estimation of the fatigue limit of components weakened either by U- and V-shaped notches or by defects, all under mode I stress distributions. When the influence of the opening angle is absent, a single formula is able to summarise both the notch sensitivity and the sensitivity to defects. Fatigue limit assessments need two material parameters, namely the plain fatigue limit and the threshold value of the long crack stress intensity factor range. The formula is compared with about 90 fatigue limits taken from the literature. Material properties and specimen geometries are given in detail. Afterwards, in the case of V-notches with large opening angles, the formula is modified, but without involving additional material parameters. A generalised Kitagawa diagram is obtained, that encompasses fatigue behaviour of stress raisers of different size, opening angle and notch tip radius.