Compression performance of a bio-inspired locally densified aluminum honeycomb structure

Abstract

Inspired by cuttlebone and spruce wood microstructures, a novel aluminum honeycomb structure with periodic S-shaped and I-shaped densified bands was developed by compressing the hexagonal cells in localized areas of regular aluminum honeycomb. The structure demonstrated excellent energy absorption performance. Quasi-static compression tests were first conducted to investigate the failure mechanisms and energy absorption characteristics of locally densified aluminum honeycomb panels and cylindrical shells under axial loads, assessing the effectiveness of local densification in enhancing energy absorption. Based on the experimental results, the deformation mechanism and load transfer paths of the locally densified honeycomb were analyzed. Finite element simulations were then employed to systematically explore the effects of geometric parameters, including cell wall thickness, cell size, and thickness-to-diameter ratio, on the energy absorption performance of the densified aluminum honeycomb cylindrical shells. The results showed that compared to regular honeycomb panels and cylindrical shells, the locally densified structures significantly improved absorbed energy, specific energy absorption, mean crushing force and crush force efficiency. The absorbed and specific energy absorption of the densified cylindrical shell increased by up to 76.50 % and 25.64 %, respectively. Cell wall thickness had the greatest impact on energy absorption, with a 203.57 % increase in specific energy absorption achieved by increasing wall thickness. Excellent energy absorption performance is achieved by a simple fabrication process alone. These findings provide effective strategies for optimizing the energy absorption performance of thin-walled structures and offer valuable insights for the design and development of energy absorption systems.