文摘
Compared with triangular, square and Kagome honeycombs, hexagonal honeycomb has superior heat dissipation capabilities, but its lower in-plane stiffness hinders its multifunctional applications. Regarding this problem, in this paper we propose a multifunctional hierarchical honeycomb (MHH) with negative Poisson¡¯s ratio (NPR) sub-structures. This MHH is constructed by replacing the solid cell walls of the original regular hexagonal honeycomb (ORHH) with two kinds of equal mass NPR honeycombs, the anisotropic re-entrant honeycomb or the isotropic chiral honeycomb. Based on the Euler beam theory, formulas for the Young¡¯s moduli of these two kinds of MHH structures are derived. Results show that by appropriately adjusting the geometrical parameters both the re-entrant honeycomb (when the cell-wall thickness-to-length ratio of the ORHH is less than 0.045) and the chiral honeycomb (when the cell-wall thickness-to-length ratio of the ORHH is less than 0.75) can greatly tune the in-plane stiffness of the MHH structure. The presented theory could thus be used in designing new tailorable hierarchical honeycomb structures for multifunctional applications.