Predicting fatigue life in commercially pure aluminium using a short crack growth model

Advances in manufacturing techniques and improvements in non-destructive inspection procedures have reduced the size of initial defects in fatigue-critical components to the scale of the microstructure. Unfortunately, the growth of these so-called short fatigue cracks is not properly characterised by conventional linear elastic or elastic-plastic fracture mechanics. However, the Navarro-de los Rios crack growth model does account for many aspects of their growth and has proved successful in predicting fatigue life of medium carbon and C-Mn steels. In consequence, the growth of short fatigue cracks in commercially pure aluminium, under fully reversed uniaxial loading, has been studied, using a plastic replication technique and modelled, using the Navarro-de los Rios crack growth equation. The predicted lifetimes are in good agreement with the actual experimental lifetimes, and compare favourably with predictions based on two previously reported crack growth models.