In this paper two types of the dynamic reliability model are proposed and compared with the Weibull distribution for the representation of fatigue crack reliability. The models are concerned with the relationship between the hazard function and reliability. One considers the differential equation form, model I, and the other takes algebraic dependence, model II. In the comparison the fatigue crack growth follows the modified Paris law which takes account of the crack closure phenomenon and the load-time history is assumed to be a stationary random process. The consideration of fatigue starts from an initial distribution of crack and becomes failure as the crack reaches a certain length distribution. The results show that the predictions followed model I and the Weibull distribution is a little conservative. However, the proposed models need only one parameter to be identified during the curve fittings. Some physical interpretations of the models are discussed. Model II is recommended among the representations of fatigue reliability due to its acceptable RMS error (less than or equal to 0.8%), physical meaning and simple appearance. Copyright (C) 1996 Elsevier Science Ltd.
