Mechanical behavior of anti-trichiral honeycombs under lateral crushing

The mechanical properties of anti-trichial honeycombs under quasi-static compression with large deformation are studied by both experiments and theoretical analysis. It is shown that the cells' collapse of the anti-trichiral honeycombs dominated by both the ligaments' rotation around the plastic hinges and the rotation of cylinders. The theoretical analytical models are established to predict both the NPR and the crushing stress of the anti-trichiral honeycombs. The analytical predictions show good agreement with the experimental results. It is shown that the crushing stress of the honeycomb decreases with the ligament's length ratio L/r, but increases with the wall thickness. As for the honeycomb's Poisson's ratio, it increases with the ligaments' length ratio and decreases with the honeycomb's deformation, while the wall thickness has no influence on it. The anti-trichiral honeycomb exhibits NPR effect only when the ligament's length ratio less than 5.5. However, when the ligaments' length ratio is more than 10, the anti-trichiral honeycomb shows positive Poisson's ratio during the whole compression. When the ligaments' length ratio is in the range of 5.5 through 10, the anti-trichiral honeycomb appears NPR under small deformation, but positive Poisson's ratio under large deformation. These light up a refer to the design of the anti-trichiral honeycombs.