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Macroscopic out-of-plane auxetic features of a laminated open-cell structure with in-plane negative Poisson’s ratios induced by bridging beam components

This paper presents the out-of-plane mechanism of a laminated open-cell structure that is exerted by a simple control of the geometric configuration. We propose two types of structural units that are assembled with beam and column members in a tetragonal system, and with the geometric difference between them being the presence of a reinforced beam. For the two unit cells, we develop finite element models according to a homogenization method and analyze the macroscopic linear and nonlinear elastic properties. The numerical results show that the cellular structure, which is bridged by additional beams, exhibits strong auxeticity with high negative values of Poisson’s ratio in the lamination direction, while retaining the in-plane negative Poisson’s ratios. We assess the sensitivity of the linear and nonlinear out-of-plane response to changes in the component geometry. Finally, we discuss the large deformation behaviors of the out-of-plane mechanisms to quantify the amounts of three-dimensional rotations of the internal components.