Extent of surface regions near corner points of notched cracked bodies subjected to mode-I loading

In the present paper, the extent of surface regions in cracked bodies subjected to mode-I loading was examined, which is important for a proper definition of finite element meshes. Different specimen geometries with and without lateral notches, representative of several engineering situations, were selected. Realistic crack shapes were considered in this analysis by employing a 3D-FE automatic crack growth technique. A triaxiality parameter (h) was calculated for different loading and geometrical parameters, namely thickness, crack length, crack shape and particularly radius of lateral notches. Criteria were defined to objectively define the extent of surface and near surface regions, S1 and S2, respectively (slope of h>0.9 for S1 and 0.1

► The extents of surface and near-surface regions in real cracked bodies are examined.
► The extents of both regions are evaluated using the slope of h triaxiality parameter.
► The surface region is one order of magnitude higher than the near-surface one.
► A linear relation between the stress concentration factor and these regions was found.
► Equations that account those regions for several cracked geometries are proposed.