Mechanical property of re-entrant anti-trichiral honeycombs under large deformation

The quasi-static mechanical properties of re-entrant anti-trichiral honeycombs made from ABS polymer are studied by both experiments and theoretical analysis. The experimental results show that the deformation of honeycomb is dominated by the bending of ligaments, the rotation of ligaments around the plastic hinges and the rigid rotation of cylinders. Based on the deformation mechanism of the cell structures exhibiting in experiments, the collapse process of the honeycomb is divided into several stages. Theoretical formulas are deduced to predict the crushing stress of the re-entrant anti-trichiral honeycombs in each stage, which are functions of the honeycomb's global strain, the cells' geometry parameters and the properties of the base material. The analytical predictions are in good agreement with the experimental results. It is revealed that the crushing stress of the honeycomb increases with the global strain and the cell-wall thickness while decreases with the ligament-length ratio. An optimal value of the cylinders' radius is found which will result in the maximum load-carrying capacity of the honeycomb. The present work is supposed to shed light on the design and fabrication of re-entrant anti-trichiral honeycombs.