Semi-empirical equations for the dynamic strength enhancement of concrete-like materials

SHPB tests are often employed to characterize the dynamic compressive strengths of concrete-like materials which are very important for the construction of reliable constitutive equations used in numerical simulations. The SHPB test data, however, need to be interpreted correctly as recent studies have revealed that the apparent compressive strength enhancement found in the SHPB tests might be due to a combination of effects such as material inherent behavior (rate sensitivity) and inertial confinement. To this end, semi-empirical equations are suggested for the dynamic strength enhancement of concrete-like materials. The equations are formulated on the basis of the recent numerical analysis that dynamic tensile tests on concrete-like materials have no inertial confinement effects and the assumption that the increments of the tensile and compressive strengths due to strain rate effects only are equal at the same strain rate. It is shown that the present semi-empirical equations are in reasonable agreement with available test data for concrete materials.