Abstract
Abstract
Energy-absorbing structures are critical to modern engineering systems, yet conventional designs often suffer from premature global instability and abrupt load-drop failures under axial compression. Here we report a high-performance bio-inspired topological grid structure designed by abstracting the spatial topological arrangement of pine nut shell sclereids, following a "characterization → biomimicry → simulation → experimentation" workflow. Scanning electron microscopy (SEM) revealed the layered microstructure of pine nut shells, showing the distribution and arrangement of regular and irregular polygonal stone cells. We introduce a Main Feature Structure (MFS) extraction algorithm that converts these biological cells into a set of designable multi-cell geometric configurations. Finite element simulations revealed that the optimized bioinspired topology (PNS-3) achieved a specific strength of 9.74 kg⁻¹ (32.2% above the honeycomb control)and a specific stiffness of 35,771.69 MPa·kg⁻¹·mm⁻¹ (62.1% improvement). Subsequent quasi-static compression tests on 3D-printed specimens demonstrated that PNS-3 attained a mass-specific energy absorption of 0.787 J/g, a 5.62-fold enhancement over the classical honeycomb configuration. This superior performance arises from a characteristic multi-peak progressive deformation mode—enabled by the synergistic interaction of triangular and parallelogram units—which promotes sequential plastic hinge formation, continuous stress redistribution, and suppresses catastrophic global instability. By integrating structural bionics, computational mechanics, and additive manufacturing, this work establishes a systematic design framework for next-generation lightweight energy absorbers with promising applications in automotive crash protection and aerospace energy dissipation.