A compliance-based method for correcting fatigue crack growth data in the presence of residual stresses

• New method developed for residual stress corrections of fatigue crack growth data. • The method is demonstrated for CT specimens fabricated using WAAM process. • The method can be used to evaluate residual stress fields in fatigue specimens. • The method can reduce experimental scatter and improve life expectancy predictions. Variations of residual stress fields in a fatigue test specimen and/or across specimens influence the fatigue crack growth rate measurements. Therefore, these variations can contribute significantly to the scatter of fatigue properties obtained on specimens, such as additively manufactured specimens without stress relief, specifically at low stress intensity factor range. To address this problem, a new compliance-based method is developed for correcting fatigue crack growth data in the presence of a residual stress fields of variable magnitude. It is based on the theoretical modelling of the propagation of an edge crack in an elasto-plastic material subjected to cyclic loading of a constant amplitude. The method is demonstrated for compact tension super duplex stainless steel (SDSS) and aluminium specimens tested without post-fabrication heat treatment. The method can be applied for both the evaluation of residual stress fields in fatigue specimens and obtaining the intrinsic fatigue properties of materials.