The re-entrant hexagonal honeycomb structure exhibits an excellent negative Poisson’s ratio effect and has been widely applied in impact protection and energy absorption systems. However, its high porosity often leads to insufficient overall stiffness and unstable deformation, thereby limiting its energy absorption efficiency. To address these issues, this study proposes a novel Overlapping Re-entrant Hexagonal Configuration (ORHC). The ORHC is constructed by embedding re-entrant regular hexagonal cells within a concave hexagonal framework, where overlapping and interlaced geometric arrangements enable synergistic support and load transfer among the cells. This design significantly enhances the structural stiffness and stability without substantially increasing the mass.Through quasi-static compression experiments and finite element analyses, the mechanical response and energy absorption characteristics of the ORHC were systematically investigated. The results indicate that the ORHC exhibits a distinct dual-plateau stress behavior during compression, demonstrating superior buckling resistance and energy absorption capability, with a specific energy absorption markedly higher than that of conventional re-entrant honeycombs. Further analysis reveals that the overlapping configuration along the Y-direction achieves optimal load transfer continuity and local stability, effectively mitigating stress concentrations and delaying structural failure. In addition, the parametric study shows that increasing the side length of the embedded re-entrant hexagonal cells enhances the energy absorption capacity under high-density conditions, whereas the absorption efficiency decreases under constant-mass constraints.Overall, the proposed re-entrant overlapping-interlaced design achieves an effective balance between lightweight characteristics and high energy absorption performance, offering new insights and theoretical guidance for the topological optimization of advanced protective structures and energy-absorbing metamaterials
Xie et al. (Fri,) studied this question.