Effect of residual stress and strain on the fatigue crack propagation in Al2024T351 structures

This study highlights the contribution of residual stress/strain fields generated in service or by manufacturing processes in an aluminum alloy structure with respect to the fatigue life. As study example to expose phenomenon, bending of an Al2024T351 structure is investigated. First a thorough mechanical characterization of a material and identifying of a plastic anisotropic behavior model is carried out. Second, residual stress and strain computation in this component is carried out. Then, fatigue tests on CT and oligocyclic specimen have been conducted on as-received and pre-deformed material to further develop a fatigue crack propagation model to predict the residual life of the component including the effect of the residual stress and strains fields.