Numerical investigation of lateral inertia effect in dynamic impact testing of UHPC using a Split-Hopkinson pressure bar

The paper focuses on investigating the lateral inertia effect in dynamic impact testing of ultra-high performance concrete (UHPC) using a Split-Hopkinson pressure bar (SHPB), based on numerical analysis. The assigned material parameters of the UHPC are obtained by calibrating the parameters of the Karagozian and Case concrete (KCC) model in LS-DYNA software. An impact analysis model of UHPC using SHPB technology is established and calibrated by the test results. A parametric study is performed to estimate the influences of the diameter and aspect ratio (AR) of the UHPC specimen, and the strain rate on the lateral inertia effect in the SHPB testing. The numerical simulation results show that: (1) the impact analysis model can predict the test results of UHPC specimens using the SHPB technique with reasonable accuracy; (2) to reduce the lateral inertia effect, the suggested diameter and AR of the UHPC specimen is 0.9–0.95 times the diameter of the bar, and 0.35–0.45 at a 100 s−1 strain rate or lower, respectively; (3) the lateral inertia effect of UHPC in the SHPB testing is more noticeable with an increase in strain rate, and the diameter of the UHPC specimen is recommended to be 0.95 times the diameter of the bar, as the strain rate is higher than 100 s−1.