Discrete Element Simulations of Dynamic Compression Failure of Inorganic Glass in SHPB Tests

Based on the discrete element algorithm (DEM), a numerical split Hopkinson pressure bar (SHPB) platform is established by the mean of particle flow code software (PFC^2D), and the feasibility of the system has been verified. The failure mode and the dynamic compressive strength of an inorganic glass specimen at different strain rates are investigated. The numerical simulation shows that the inorganic glass exhibits typical brittle characteristics during dynamic compression, and its compressive strength is significantly affected by the strain rate. The Young’s modulus, however, is strain rate insensitive. The failure mode of the specimen is affected by the boundary friction as well as the Poisson ratio. In the case of frictional contact, the initial micro-cracks within the specimen are distributed in a triangular zone due to the combined effect of longitudinal pressure and frictional force. With the increase of the longitudinal stress, the transverse tensile stress creates the longitudinal cracks, resulting in the axial splitting. The failure mode in the case of frictionless contact differs from the frictional case, in which no triangular crack zone exists. Moreover, the value of Poisson ratio affects the failure mode as it results in the transverse tensile stress during dynamic loading. Numerical simulations of dynamic Brazilian compression are also conducted to support future experimental works. It shows that Brazilian disk starts failure at the center in the moderate strain rate and the macroscopic splitting tensile strength is strain rate dependent.