3D-printed trabecular-bone bio-inspired beams for lightweight structural applications

This study examines the flexural behaviour of 3D-printed trabecular-bone-inspired beams for lightweight structural applications and clarifies the structural role of internal bone-like topology under three-point bending. Two trabecular families (B1 and B2), each with three pore-density configurations (S, M and L), were fabricated by fused filament fabrication using ASA and Vibers PLA (VPLA). Twenty-four beams, including one repeat specimen per configuration, were tested under monotonic quasi-static three-point bending and supported by geometrically nonlinear elastic finite element analyses. The key novelty lies in the combined experimental-numerical comparison of two trabecular architectures across pore density and filament type while keeping the external beam envelope constant. The results show that topology strongly governs the global response. Small-pore beams provide the highest initial stiffness, while the B2 architecture generally improves stiffness retention and load redistribution relative to B1. The highest stiffness was measured for B2-S-VPLA (122,190 N/m), and the B2-VPLA series also exhibited favourable stiffness-to-mass ratios and more gradual post-peak softening. The FE models reproduced the initial stiffness ranking and located peak stresses at strut junctions and pore edges, consistent with observed crack-initiation regions. These findings show that trabecular bone-inspired webs can provide lightweight, damage-tolerant beam concepts and that bio-based VPLA can be a viable alternative to ASA for such printed structural components.