Additively manufactured bioinspired multilayer sandwich structures with varied core configurations under out-of-plane compression.

In this research, novel bio-inspired multilayer sandwich panels were fabricated by Multi Jet fusion and evaluated under quasi-static out-of-plane compression to examine the influence of core topology, cell size, intercell spacing, and layer orientation. The rhombic and hexagonal cores exhibited superior performance, with absorbed energies of 440.46 J and 363.96 J, respectively, and specific absorbed energies (SAE) of 4.50 J/g and 4.18 J/g. In contrast, the square and circular cores absorbed less energy, 264 J and 270 J, with SAE of 3.83 J/g and 3.60 J/g, respectively. Reducing the inscribed diameter from 2.0 to 1.5 mm increased peak load by between 10 and 15%, while energy absorption rose by 13% in circular cores and 6% in hexagonal cores, with SAE gains of 10 and 5%, respectively. Increasing intercell spacing from 2.0 to 2.5 mm improved energy absorption by 12% in circular cores and 14% in hexagonal cores, with SAE increases of 5 and 7%. Alternating corrugation orientation further enhanced performance, raising energy absorption by 20% in circular cores and 22% in hexagonal cores. In general, energy absorption was governed by progressive failure mechanisms including yielding, buckling, delamination, and cracking. These insights bridge additive manufacturing and bio-inspired design with structural engineering by linking core topology and geometry to measurable gains in peak load, absorbed energy, and specific absorbed energy.