A finite element analysis for using Brazilian disk in split Hopkinson pressure bar to investigate dynamic fracture behavior of brittle polymer materials

An experimental method of using the Brazilian disk specimen in the split Hopkinson pressure bar (SHPB) apparatus is proposed to perform dynamic fracture testing of brittle materials. The average force on the specimen, which is obtained according to the one-dimensional elastic wave propagation theory, is adopted to determine the dynamic stress intensity factor (DSIF) by extending the quasi-static formula of the stress intensity factor (SIF) to impact loading condition. A finite element model for the Brazilian disk-SHPB dynamic fracture testing system is established. The numerical analysis confirms the validity of the one-dimensional experimental measuring principle. The effects of rise time of incident stress pulse and specimen geometry are discussed. It is shown that there exists a matching relation between the specimen and the pressure bar system.