Physical and numerical evaluation of rock strength in Split Hopkinson Pressure Bar testing

Split Hopkinson Pressure Bar (SHPB) testing was used to evaluate the strength characteristics of sandstone under uniaxial compressive loading. The physical results suggest that rock strength increases under dynamic loading. A hybrid bonded particle-finite element model was used for numerical simulation of SHPB tests. A parameter called rock strength enhancement coefficient was introduced which is multiplied by the relative velocity of particles at the contact points to increase the bond strength between the particles. It is shown that a much better match between the physical and numerical results is realized if this enhancement coefficient is applied in the numerical simulation.