Characterization of 3D-Printed Bio-Inspired Structural Cores Under Static and Dynamic Loading

Sandwich structures are increasingly employed in high-performance applications due to their excellent strength-to-weight ratio. However, their mechanical reliability often depends on the structural core, which remains susceptible to failure under shear and flexural loads. Additive manufacturing (AM) enables the design and fabrication of complex, bio-inspired core architectures, such as those derived from Voronoi tessellations, which can potentially enhance energy absorption and mechanical performance. This study investigates the mechanical behavior of PLA-based cellular cores, produced via Fused Filament Fabrication (FFF), under quasi-static and intermediate strain rates (up to 33 s−1). Two infill geometries were compared: a standard cubic pattern and an open Voronoi-based structure inspired by biological morphologies. The results demonstrate strain-rate sensitivity in both configurations, characterized by increased stiffness and peak stress at higher loading rates. While the Voronoi structure exhibited lower maximum strength compared to the cubic pattern, it demonstrated a more gradual post-peak softening, indicating potentially superior energy dissipation capabilities. These findings support the potential of bio-inspired, additively manufactured structures in energy-absorbing applications.