Spherical indentation cracking in brittle materials: An XFEM study

This work aims at characterizing the formation of cone-cracks in brittle materials upon spherical indentation. The cone-cracking is simulated by the extended finite element method (XFEM) in Abaqus / Standard. The element size-dependency is reduced by scaling the damage initiation strength based on mean stress criterion and calibration techniques. The formation of a kinked-cone-crack is observed when the indenter comes into (second) contact with the surface part outside the ring crack. After analyzing the effects of friction, Poisson's ratio on cone-crack evolution, a database for enhanced Roesler's constant, which considers the effect of cone-crack-kinking, is provided by performing systematic XFE analyses. This database can be used for the fracture toughness evaluation in brittle materials.