An equivalent block method for computing fatigue crack growth

This paper builds on a development in the science of fatigue crack growth to present an equivalent spectrum block method for predicting fatigue crack growth under variable amplitude loading. This approach is based on the generalised Frost–Dugdale model and forms an analytical basis for the observation of a near exponential relationship between crack length and fatigue life under variable amplitude loading. A method for extending the Frost and Dugdale model from Region I through to Region III is also presented.