On the mechanical behavior of additively manufactured asymmetric honeycombs

From a design perspective, there are four decisions that need to be made when integrating cellular materials such as lattices and honeycombs into a structure: selection of the unit cell type, distribution of the size of the cells across the structure, optimization of individual cell walls/struts and junction thicknesses, and finally, integration of the cellular material with the outer form of the larger structure it is a part of. In this paper, we explore an alternative approach to designing cellular materials, borrowing concepts of symmetry from mathematics and the arts to manipulate 2-dimensional square honeycombs of uniform thickness, starting from a regular, periodic square, gradually varying symmetry and the number of shapes to create a range of forms. We report results of compression testing of specimens made with the Fused Deposition Modeling process, and study the effective specific properties of the honeycombs with regard to their peak stress at failure, densification strain and energy absorption. We report weak to no correlation to the first two of these, but demonstrate how asymmetry and negative space may be leveraged to formulate design principles for energy absorption.