Impact performance of steel-RULHDCC double-layer sandwich panels subjected to repeated impact loads

Steel-concrete-steel (SCS) sandwich composite can make the full use of the excellent tensile strength of steel and compressive strength of concrete, leading to excellent impact resistance of the sandwich structure. To further improve the impact performance, on the material side, the study added rubber powder into the ultra-lightweight high-ductility cement composite (ULHDCC) to develop the rubberized ULHDCC, i. e., RULHDCC; and on the structural side, the study utilized hybrid shear connectors and double-layer sandwich. The drop-weight impact test reveals that the sandwich panel shows an obvious punching failure mode under repeated impact loads. The parametric study reveals that adopting double-layer structure and hybrid shear connectors can reduce the impact damage degree of the structure. Increasing the spacing of shear connectors and the content of rubber can increase the energy absorption ability of the structure. The numerical simulation using LS-DYNA was conducted in the study. It was proposed to simulate the repeated impact in the way of defining multiple drop hammers with different initial heights falling at the same time. The numerical simulation can well predict the failure and dynamic responses of the sandwich subjected to impacts. © 2023 Science Press. All rights reserved.