The in-plane non-linear compression of regular honeycombs

Abstract

A theoretical analysis is made of the in-plane uniaxial compression of regular honeycombs made from a range of materials. Both the elastic and elastic-plastic responses are considered, as a function of the honeycomb density, for strains until the faces touch. The stress–strain relationship and lateral expansion are predicted for loading in the symmetry axis directions, for deformation modes with and without vertex rotation. For an elastic honeycomb, compressed parallel to one set of faces, a buckling mode with vertex rotation gives the lower stress, for strains exceeding 10% in honeycombs with single thickness vertical faces, and 15% strain for double-thickness faces. If the material yields, or other forms of non-linearity occur, there can be strain softening, which leads to strain localisation. Deformation mechanisms are linked to the material response and the honeycomb density, and are compared with experiments on polymeric honeycombs.