Experimental and analytical studies on a novel steel-PU foam-concrete-tube multilayer energy absorbing panel under impact loading by a cylinder head

A novel steel-polyurethane foam-concrete-tube multilayer energy absorbing panel (SFCTMEAP) was proposed in this paper, and it could be attached to the surface of the protected structure to mitigate impact loading. The impact tests on the SFCTMEAP were performed via using a drop-weight impact test machine. The investigated parameters in the impact tests included the thickness of concrete core as well as thickness and width of the steel tube. All tested specimens exhibited a combined failure mode, consisting of the local indentation of energy absorbing panel and the collapse of polyurethane foam-filled steel tubes. The energy absorbing performance of SFCTMEAP under impact loading was discussed in detail. Additionally, a three-degree-of-freedom model was proposed to obtain the displacement response of the SFCTMEAP, and the analytically-calculated displacement–time histories agreed well with the experimental results.