Sandwich composites containing thermoplastic core structures manufactured by 3D printing for defense industry applications

This paper investigates the effect of material type, shape and cell size of cores on impact energy absorption properties. For this purpose, thermoplastic cores were prepared by 3D printing and compared with commercially available composites containing aluminum and aramid cores. The impact energy absorption properties were evaluated using “falling arrowhead” impact puncture tests. Obtained results showed that composites containing thermoplastic cores had significantly higher impact energy absorption compared to reference composites. Structures with a small cell area, especially those with a rectangular shape and parallel cell arrangement, performed the best. In contrast, composites with aramid and aluminum cores, despite their lower weight, had worse impact properties. It was also shown that increased energy absorption by thermoplastic structures was associated with higher composite weight, which may be an important factor in applications requiring optimization of mass and impact-ballistic resistance.