Experimental and numerical study on the impact response of the steel-concrete-steel-foam-filled-tube energy absorbing structure

A novel energy absorbing structure is proposed and can be fixed on the front of protected structures to reduce the impact-induced damage. This energy absorbing structure consists of nine polyurethane foam-filled steel tubes (PUFFSTs) and a steel-concrete-steel sandwich panel (SCSSP) and is named steel-concrete-steel-foam-filled-tube energy absorbing structure (SSEAS). The present study investigates the energy dissipation characteristics and dynamic responses of SSEAS through both experimental and numerical analyses. All specimens exhibited the same failure mode, including the collapse of the centre PUFFST and the local indentation of the SCSSP. The investigated parameters contain the thickness and width of the steel tube, thickness of concrete core and the initial momentum of the drop weight. A comprehensive discussion is presented on the impact response and energy dissipation performance. The results indicate that the thinner concrete core would result in larger deformation but shallower local indentation. Additionally, raising the width and thickness of the steel tube would result in higher energy absorbing capacity and larger proportion of energy dissipation of PUFFSTs. The numerical studies also show that higher initial momentum of the drop weight would induce a longer duration and larger energy dissipation of PUFFSTs.