Edge cracks in plastically deforming surface grains

A selection of surface crack problems is presented to provide insights into Stage I and early Stage II fatigue crack growth. Edge cracks at 45 degrees and 90 degrees to the surface are considered for cracks growing in single crystals. Both single crystal slip and conventional plasticity are employed as constitutive models. Edge cracks at 45 degrees to the surface are consi dered that either (i) kink in the direction perpendicular to the surface, o r (ii) approach a grain boundary across which only elastic deformations occ ur. (C) 2001 Editions scientifiques et medicales Elsevier SAS.