Spherical indentation for brittle fracture toughness evaluation by considering kinked-cone-crack

This work aims at evaluating the fracture toughness of brittle materials by spherical indentation. The cone-cracking is simulated by the extended finite element method (XFEM) in Abaqus. The formation of a kinked-cone-crack is observed when the indenter comes into (second) contact with the surface part outside the ring-crack. The effects of friction, Poisson's ratio and cone-crack kinking on the Roesler's constant κc are analyzed. Based on numerical results, the Roesler's method for evaluating the fracture toughness is enhanced by considering kinked-cone-crack. By performing systematic XFE analyses, a database for enhanced Roesler's constant κc | kink is provided for the fracture toughness evaluation of brittle materials. Finally, the proposed method is verified by conducting spherical indentation tests on soda-lime glass specimens.