Application of the strain-based FAD to failure assessment of surface cracked components

Purpose – The purpose of this paper is to validate the strain-based failure assessment diagram (SB-FAD) approach for surface cracks in components subjected to displacement controlled boundary conditions. Design/methodology/approach – Numerical analyses are performed for several crack geometries and materials representative for aerospace applications. The performance of the SB-FAD is judged by comparing numerically calculated J-integrals to respective analytical estimates, using both Options 1 and 2 approximations. Findings – In the most cases, both Options 1 and 2 SB-FAD method results in reasonably conservative J-estimates. Exceptions are for surface cracks in a pressurized vessel made of a material with low-strain hardening, for which Option 2 assessment produces non-conservative results. In contrast, Option 1 assessment is conservative for all geometries considered. In general, Option 1 results in a considerable overestimation of the crack driving force, whereas Option 2 produces rather accurate results in many cases. Originality/value – The results demonstrate both the potential of the SB-FAD method and needs for its further improvements.