Experimental Investigation of the Post-Fire Impact Resistance and Energy-Absorbing Characteristics of Polyethylene Cored Lightweight Metal Sandwich Panels

To investigate the effect of different fire loading time and stitching methods on the post-fire impact resistance of the polyethylene cored sandwich panels, quasi-static perforation, and low-velocity impact tests were conducted after real fire tests. The temperature distribution, deformation, failure behavior, load-carrying capacity, and energy absorption capacity of the panels were explored and compared. The effects of key parameters such as the stitching method, fire time, and impact energy on the load versus displacement curves and energy absorption were discussed in detail. In addition, a theoretical model was developed to predict the plastic strain of sandwich panels under the low-velocity impact, and the results showed that when the height of the falling hammer is constant, the depression value of the upper surface center point (${\delta _1}$delta 1) and the depression value of the lower surface center point (${\delta _2}$delta 2) are both linearly related to ${1 \over {\sqrt {{{({T_m} - {T_r})}<^>n} - {{\left({T - {T_r}} \right)}<^>n}} }}$1(Tm-Tr)n-T-Trn.