MECHANICAL PROPERTIES OF MULTI-ARC CONCAVE HONEYCOMB STRUCTURE WITH ADJUSTABLE POISSON'S RATIO

A new type of multi-arc concave cell with adjustable Poisson's ratio is proposed. The structures of positive Poisson's ratio, zero Poisson's ratio and negative Poisson's ratio can be designed by adjusting the arc angle. The analytical expressions of the equivalent Poisson's ratio and the equivalent elastic modulus are obtained by using the energy method, and the results are in good agreement with the finite element results. Based on the proposed new cellular structure, the impact deformation failure behavior and the energy absorption per unit mass of positive Poisson's ratio structure, zero Poisson's ratio structure and negative Poisson's ratio structure under low-speed and high-speed impact are discussed by numerical method. It is found that under low-speed impact, the local deformations of the three Poisson's ratio (positive/zero/negative) structures are different. During high-speed impact, the inertia effect makes the local deformation concentrated at the impact end, and the cell deformation modes of the three Poisson's ratio (positive/zero/negative) structures are different. The negative Poisson's ratio structure shows excellent energy absorption regardless of low-speed or high- speed impact. With the increase of wall thickness, the energy absorption effect of the structure is significantly enhanced.