MODIFICATION OF DIF-STRAIN RATE CURVE OF CONCRETE-LIKE MATERIALS IN NUMERICAL SIMULATION OF SHPB EXPERIMENTS

Numerical simulation is an effective technique to study the response of concrete-like materials to dynamic loads. For predicting the concrete-like materials structure response to dynamic loads, it's important to input the DIF-strain rate curve exactly in numerical simulation. The data in dynamic compressive experiments of concrete-like materials since 1990 was collected, and the inertia-induced effect on dynamic strength of material was stripped out to obtain DIF_ε-logε curve. It is discovered that DIF_s and DIF_i increase with specimen size. At the same time, DIF_i of concrete-like materials increase less with the strain rate when the quasi-static strength of the materials increases. New curve and semi-empirical formula curve were compared, which show that the new curve was coincided with DIF_ε of experiments better than the semi-empirical formula at high strain rate. Furthermore, the superiorities of new curve are validated by comparing the DIF recommended by CEB with the new curve as the numerical inputs.