Self-similar hierarchical honeycombs in two different fractal layouts: A comparative study of the in-plane crushing behaviors.

This paper provides a new avenue for the development of cellular structures. By mimicking the chemical structural formula of the TpPB-Fe coordination polymer, a new self-similar hierarchical honeycomb was proposed. With respect to the existing self-similar hierarchical honeycomb in the literature which was constructed by replacing every three-edge vertex of the regular hexagonal honeycomb with a smaller hexagon, the new one is created by setting the fractal position at the midpoint of the cell walls of the regular hexagonal honeycomb. What I am really curious about is the difference in mechanical properties between the two self-similar hierarchical honeycombs. Finite element (FE) model was first built and validated by comparing against the existing theoretical data. Subsequently, the in-plane crushing behaviors of the honeycombs under different impact velocities were fully investigated by FE simulations. The deformation modes, plateau stress as well as the energy absorption capability of the honeycombs were studied. Different macroscopic and microscopic deformation patterns between the two hierarchical honeycombs were observed. The plateau stress of the new hierarchical honeycomb is higher than that of both the existing counterpart and the basic regular hexagonal one. Under low- and medium-velocity impact loading, the new honeycomb with low fractal ratio (α) has superior energy absorption capability with respect to the existing counterpart and the basic regular hexagonal one. However, the new honeycomb will lose its advantage in energy absorption when the fractal ratio or the impact velocity is large. • A new self-similar hierarchical honeycomb was proposed. • In-plane crushing behaviors of both the new and the existing self-similar hierarchical honeycombs were studied. • Correlations among the deformation, stress and energy absorption of the hierarchical honeycombs were discussed. [ABSTRACT FROM AUTHOR]