Finite Element Analysis on Mixed-Mode Dynamic Fracture Experiments of Centrally Cracked Brazilian Disks With Crack Face Contact

Abstract

To verify the feasibility of measuring brittle material’s complex-mode dynamic fracture toughness, the centrally cracked Brazilian disk (CCBD) specimen was tested under dynamic loads in the split Hopkinson pressure bar (SHPB) system in view of crack face contact. The 3D SHPB-CCBD finite element model was established to calculate dynamic stress intensity factors (DSIFs) of the CCBD specimen under different loading conditions. Results show that, the fracture time condition of stress equilibrium is necessary for calculating DSIFs through extension of the quasi-static stress intensity factor (SIF) formula with crack face contact to the dynamic expression. The crack face contact leads to changes of the crack face stress, and has a significant impact on the mode-II DSIFs. The test values of mode-II DSIFs will be unreasonably larger without regard to the crack face contact.