Mechanical properties of re-entrant chiral anisotropic honeycomb

Abstract

In this paper, we proposed a honeycomb structure with enhanced anisotropy in the orthogonal direction with a re-entrant chiral hybrid deformation mechanism. The analytical formulas for the equivalent Poisson's ratio and normalized Young's modulus were derived based on the theory of the Timoshenko beam under small static deformations and verified by experiments and finite element simulations. Parametric analysis demonstrated the extreme anisotropy of this structure in the orthogonal direction, achieving a Poisson's ratio −10 or lower in one direction, while remaining nearly zero in the other direction. This property allowed the structure to be designed into a tubular stent that remained stable along its axial length when subjected to a compressive load in the radial direction. However, the stent underwent significant contraction in the radial direction when a compressive load was applied along the axial direction. This stent is expected to have biomedical applications to solve problems associated with cardiovascular obstruction, esophageal obstruction, and airway stenosis.