Bending and benchmark of zero Poisson’s ratio cellular structures

This work describes the bending performance of a zero Poisson’s ratio (ZPR) cellular structure made from the tessellation of hexagons and thin plates. This particular ZPR configuration allows achieving large out-of-plane deformations and tailored in-plane and out-of-plane mechanical properties. We present a series of analytical models, finite element simulations and experimental tests to evaluate the bending capability of these cellular structures. A comparison of the out-of-plane bending behavior of six different types of cellular topologies with the same relative density of the ZPR honeycomb has also been carried out by using three-point bending tests. Further parametric analyses have also been performed to determine the dependence of the equivalent bending modulus versus the geometric parameters that define the ZPR honeycomb. The novel ZPR lattices show the highest bending compliance at large strains, and highly tailorable mechanical properties for the design of composite structures for airframe morphing applications.