A systematic numerical and experimental study into the mechanical properties of five honeycombs

Honeycombs are engineered cellular materials that often show superior specific strength, stiffness and energy absorption compared to solid materials. As a consequence they have found numerous applications across engineering fields. The development of additive manufacturing (AM) technologies has initiated an abundance of studies into novel honeycombs as historic manufacturing constraints are lifted. Investigations have been focused on improving or tailoring a given property but very few have focused on isotropy, and little has been done to bring together different patterns under the same manufacturing and experimental conditions. In this study, AM has been used to manufacture nominally identical honeycombs based on differing unit cells, in a range of orientations and densities. Elastic and plastic properties for the hexagon, triangle, square, re-entrant and double-V honeycombs have been obtained through mechanical testing. The elastic properties of these honeycombs have been modelled for all possible in-plane loading directions using minimal computational resources. The effect of orientation and density has been presented, confirming the level of in-plane isotropy for dense honeycombs with regards to Young's modulus, Poisson's ratio, yield strength and compressive strength. Insights have also been gained into how these properties vary with relative density. These results provide a basis for comparison with future work on honeycombs.