Synergistic enhancement of load-bearing and energy-absorbing performance in additively manufactured lattice structures through modifications to conventional unit cells

Abstract

The unit cell configuration of lattice structures critically influences their load-bearing and energy absorption performance. In this study, three novel lattice structures were developed by modifying the conventional FBCCZ unit cell through reversing, combining, and turning strategies. The designed lattices were fabricated via laser powder bed fusion (LPBF) using Ti-6Al-4V powder, and the mechanical properties, energy absorption capacity, and deformation behaviors were systematically investigated through quasi-static compression tests and finite element simulations. The results demonstrate that the three modified lattices exhibit superior performance over the conventional FBCCZ structure in terms of fracture strain, specific yield strength, specific ultimate strength, specific energy absorption, and energy absorption efficiency, thereby validating the efficacy of unit cell modifications in enhancing lattice performance. Notably, the CFBCCZ and TFBCCZ lattices significantly outperform both the FBCCZ and RFBCCZ lattice structures in load-bearing and energy absorption. While TFBCCZ shows marginally higher specific elastic modulus and energy absorption efficiency than CFBCCZ, the latter achieves superior energy absorption due to its highest ultimate strength and densification strain. Finite element simulations further reveal that the modified lattices, through optimized redistribution and adjustment of internal nodes and struts, effectively alleviate stress concentration during loading. This structural modification enhances the structural integrity and deformation stability under external loads, enabling a synergistic enhancement of load-bearing capacity and energy absorption performance.