Synergistic collapse design of a multi-feature bioinspired lattice for multifunctional mechanical optimization

Traditional lattice structures often suffer from mechanical performance trade-offs among strength, deformation stability, and energy absorption capacity. To address these limitations, we propose a novel bio-inspired design—the Functionally Graded Layered Circular Face-Centered Cubic (FGLCFCC) lattice—drawing inspiration from the hierarchical microstructure of pomelo peel. This structure integrates vascular bundle-inspired reinforcing domains surrounded by localized gradient transition zones. Together, these bio-inspired features induce a coordinated collapse mechanism, effectively suppressing catastrophic failure and enabling a stable, high-energy-absorbing plateau response. Compared to the traditional FCC lattice, the FGLCFCC structure demonstrates substantial improvements in specific strength (16.4 %), specific energy absorption (21.6 %), and crushing force efficiency (16.3 %) under Z-direction loading. In addition, a parametric study was conducted to evaluate the effects of the gradient deviation coefficient and loading direction on the mechanical response. Results indicate that the structural response varies with the loading direction, where Z-direction loading, aligned with the gradient orientation, facilitates a more uniform collapse process and higher energy efficiency. While individual property enhancements may not be extreme, the FGLCFCC lattice achieves a well-balanced integration of strength, stability, and energy absorption. This highlights the potential of a multi-bio-inspired integration strategy as a robust pathway for designing next-generation high-performance lattice materials.