In-plane stiffness of the anisotropic multifunctional hierarchical honeycombs

The anisotropic hexagonal honeycomb is one of the common honeycombs. To increase its in-plane stiffness greatly, in this paper the anisotropic multifunctional hierarchical honeycomb (AMHH) is proposed. It is constructed by replacing the solid cell walls of the original anisotropic hexagonal honeycomb (OAHH) with the equal mass isotropic substructures, triangular or Kagome honeycombs. Two kinds of AMHH structures are proposed. One corresponds to the OAHH with 120° angles between the jointed cell walls, the other one corresponds to the OAHH with angles between the jointed cell walls different from 120°. Through Euler beam theory, the in-plane stiffness of these two kinds of AMHH is analyzed. Results show that the triangular honeycomb substructures could greatly increase the in-plane stiffness of the AMHH by 1.5 times or even more than 100 times, depending on the thickness-to-length ratio of the oblique cell wall of the OAHH. And the validation of the range for the thickness-to-length ratio of the oblique cell wall, which is related to the density of the OAHH, could reach to 0.1. The present theory could be used for designing new tailorable anisotropic hierarchical honeycomb materials for multifunctional applications.