Competition between in-plane buckling and bending collapses in nanohoneycombs

The classical hexagonal honeycomb theory for the uniaxial loading case, developed by Gibson and Ashby, considers buckling of the cell walls parallel to one symmetry axis. In general, buckling may also occur in the cell walls inclined with respect to the two symmetry axes. Therefore, in this letter, under the uniaxial loading conditions, we derive the critical stresses of buckling and bending collapses of nanohoneycombs, for which the surface effect is included. Furthermore, the competition between the two failure modes is studied. The present theory could be used to design new nanoporous materials,e.g., scaffolds for the regenerative medicine or energy-absorption materials.