Bio-Inspired Lattice Exhibiting Strain-Rate Insensitive Energy Absorption under Multi-Angle Dynamic Impact

Lattice structures are promising for lightweight impact protection, yet conventional BCC and FCC designs remain prone to vertex stress concentration, localized collapse, and unstable performance across strain rates and impact angles. Drawing inspiration from deep-sea glass sponges, this study introduces a vertex-modified BCC (VMBCC) lattice that shifts corner connections and integrates a triaxial cross-support to reconfigure load-transfer paths. 316L VMBCC, BCC, and FCC lattices of comparable relative density were fabricated via selective laser melting and evaluated through drop-weight axial impact tests, multi-angle responses were obtained through validated finite element models. The VMBCC lattice forms a global diagonal deformation band rather than localized shear or layer-wise collapse, yielding markedly enhanced performance. Under axial impact, its specific plateau stress increases by 51.04% and 80.65%, and its specific energy absorption by 50.00% and 76.84%, compared with BCC and FCC lattices. Across strain rates from 238 to 1428 s -1 , the VMBCC maintains its deformation mode and achieves SEA up to 16.11 J/g, demonstrating clear strain-rate-insensitive energy absorption. Finite element analysis further confirms its superior performance under oblique loading. These findings establish a robust bio-inspired lattice architecture delivering stable, high-efficiency energy absorption under diverse dynamic impact conditions.