Low velocity impact study of polyurethane foam in‐situ foamed honeycomb sandwich structure

Abstract To enhance the impact resistance of aluminum honeycomb sandwich structure, the honeycomb was foamed in situ using polyurethane foam (PU). Experimental and numerical studies were conducted on the drop weight impact response of empty honeycomb sandwich structure (SH) and PU‐reinforced honeycomb sandwich structure (SHP), and scanning electron microscope (SEM) was conducted to acquire impacted areas, and the peak load was theoretically predicted. The results showed that PU with a filling density of 140 kg/m 3 not only enhanced the peak load of the honeycomb sandwich structure by 12.83% and its stiffness by 26.7%, but also accelerated energy absorption and transfer, thereby effectively reducing the indent diameter of the front face sheet by 31.99% and its maximum deflection by 10.27%. Compared to the PU with a density of 60 kg/m 3 , the one with a density of 140 kg/m 3 exhibited a better enhancement in its impact resistance. Both the increase in impact energy and the enlargement of the punch radius highlighted the advantages of the SHP in enhancing the impact resistance. Highlights The manufacturing process of SHP was described. The impact response on SHP was studied experimentally and numerically. SHP enhanced the impact resistance and accelerated energy transfer. The peak load of SHP was theoretically predicted. The increase in impact energy and punch radius highlighted the advantages of SHP.