Experimental and numerical studies on novel stiffener-enhanced steel-concrete-steel sandwich panels subjected to impact loading

In this study, a new stiffener-enhanced steel-concrete-steel (SESCS) sandwich panel was proposed with the aim of improving the impact resistance of the traditional steel-concrete-steel (SCS) sandwich panel. The drop-weight impact tests on the SESCS sandwich panels were conducted to obtain their failure modes, impact force and displacement responses. The effects of concrete core thickness, steel plate thickness, presence of stiffeners, and drop height on the dynamic responses of SESCS sandwich panels were experimentally revealed. All the tested panels exhibited the combined failure mode of global flexure and local indentation, and the SESCS sandwich panel demonstrated improved impact resistance. As compared to the SCS sandwich panel without stiffeners, the peak impact force and post-peak mean force of the SESCS sandwich panel were enhanced by 41.56% and 31.7%, respectively, while the maximum displacement was reduced by 30.21%. In addition, the impact resistance of the SESCS sandwich panel was found to be improved by increasing the thickness of steel plate and concrete core. The Finite Element (FE) models of the SESCS sandwich panels under impact loading were developed and validated with the experimental results. The FE analyses were subsequently conducted to reveal the damage evolution of concrete core during impact, and the concrete core exhibited punching shear failure at the impact zone and flexural failure at the free side of the panel, respectively. Furthermore, parametric studies were conducted to investigate the influences of impact velocity, hammer mass, impact energy and momentum of the hammer on the impact responses of SESCS sandwich panels. •A new stiffener-enhanced steel-concrete-steel (SESCS) panel was proposed for impact resisting.•The behaviors of the SESCS panel under impact loading were studied through impact tests and FE simulations.•The SESCS panel exhibited superior impact resistance comparing with the traditional SCS panel.•The influences of variant parameters on the impact performances of the SESCS panels were studied.