Radial inertia effect analysis of UHPC impact test based on SHPB

To discuss the radial inertia effect of UHPC impact test using SHPB, the numerical simulation and analysis using the software LS-DYNA are conducted by varying the specimen diameter, length-diameter ratio and constant strain rate loading. The dynamic damage behavior of UHPC material is fitted by optimizing the parameters of Karagozian-Case-Concrete (KCC) damage model in LS-DYNA. An impact model of UHPC is established and calibrated by SHPB experiments. The parameters of different UHPC specimens with or without pulse shaper were analyzed, and their effects on the radial inertia effect in SHPB test were discussed. The results show that: (1) to realize one-dimensional stress wave during the loading and stress equilibrium of specimen, the diameter of UHPC specimen is suggested to be 0.90−0.95 times the bar diameter; (2) the limited effect of aspect ratio of UHPC specimen on the stress equilibrium is observed, so the aspect ratio of UHPC specimen is suggested to be 0.35−0.45 for satisfying the uniformity of steel fiber distribution in fabrication and ensuring one-dimensional stress wave propagation; (3) the constant strain rate loading is an important prerequisite for eliminating the radial inertia effect of UHPC materials in SHPB impact test.