Study on the out-of-plane mechanical properties of foam-filled paper honeycomb

In this study, a quasi-static compression experiment system was employed to investigate the enhancing mechanism for polyurethane foam filling on the mechanical properties of paper honeycomb structures. Based on the comparative analysis of single-cell and honeycomb plate samples, it is revealed that cell side length, wall thickness, foam strength, and interfacial bonding force exert synergistic regulatory effects on out-of-plane load-carrying capacity. Experimental results indicate that reducing the cell side length and increasing the wall thickness can significantly improve the structural properties, while the peak stress, plateau stress, and energy absorption of foam-filled paper honeycomb increases by 25% to 450% compared with those of unfilled honeycomb. Notably, the cooperative load-bearing capacity exceeds the simple superposition effect of foam and bare honeycomb. Finally, a predictive model for the plateau force of foam-filled paper honeycomb is proposed, with experimental verification errors below 10%. This model provides a theoretical framework for optimal design of lightweight composite honeycomb structures.