AbstractThe present study conducts experimental, numerical, and analytical investigations of the responses of double-layer steel-rubberized ultra-lightweight cement composite (RULCC)-steel sandwich panels subjected to concentrated impact loading. Seven full-scale steel-concrete-steel (SCS) panels are designed and fabricated with different numbers of concrete layers, degree of composite action, type of shear connectors, and proportion of added rubber powder. The influences of these design parameters on failure mode and response behavior are quantified and discussed. Advanced finite element (FE) simulation is performed in LS-DYNA software to extract more information on the strains, stresses, and energy absorption of the panel during impact. Finally, a single-degree-of-freedom (SDOF) model and a two-degree-of-freedom (TDOF) model are developed to predict displacement-time and load-time responses of the double-layer SCS panels based on the quasi-static load-displacement relationship also proposed here. Comparisons with test results demonstrate that the SDOF model overpredicts peak deformation of the panel if the hammer weight is much greater than the effective panel weight. In contrast, both the FE and TDOF models provide a much more accurate prediction of the impact responses of double-layer SCS panels, including peak impact force, peak deformation, and residual deformation.