In-plane dynamic crushing of chiral and anti-chiral honeycombs

The deformation modes and energy absorption properties of chiral and anti-chiral honeycombs with negative Poisson's ratio under in-plane dynamic crushing were studied by means of numerical simulations. The results show that the deformation mode of the chiral family honeycombs at low impact velocities consists of two different stages: the first is the collapse of the ligaments and then is the collapse of the circular nodes. The deformation mode appears as the crushing of circular nodes and ligaments layer by layer at high velocities and a transitional mode with part features of both the low and high velocities modes at moderate velocities. The localized bands transit from the fixed end to the impact end as the impact velocity increases. When the velocity is low or moderate, the chiral family honeycombs display the dynamic auxetic responses. The results provide us a certain understanding of the dynamic behaviors and energy absorption properties of two-dimensional auxetic cellular materials and lay the foundation for understanding the impact behaviors of three-dimensional auxetic foam materials.