Inspiration from Nature: Additively Manufactured Multi-Layer Bio-Inspired Sandwich Structures with Varied Cell Geometries and Configurations under Out-of-Plane Compressive Load

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 percent, while energy absorption rose by 13 percent in circular cores and 6 percent in hexagonal cores, with SAE gains of 10 and 5 percent, respectively. Increasing intercell spacing from 2.0 to 2.5 mm improved energy absorption by 12 percent in circular cores and 14 percent in hexagonal cores, with SAE increases of 5 and 7 percent. Alternating corrugation orientation further enhanced performance, raising energy absorption by 20 percent in circular cores and 22 percent 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.