Auxetic mechanical metamaterials with diamond and elliptically shaped perforations

Mechanical metamaterials are systems which derive their mechanical properties from their structure rather than their intrinsic material composition. In this work, we investigate a class of highly anisotropic mechanical metamaterials designed by the introduction of diamond and elliptically shaped perforations which possess the ability to show auxetic behaviour. By the use of finite element simulations, we show how these highly tuneable systems have the potential to exhibit a large range of Poisson’s ratios, ranging from highly positive to giant negative values, simply by altering the geometric parameters and orientation of the perforations. The anomalous properties of these systems have also been shown to be retained over significant tensile strain ranges, highlighting the vast potential applicability and functionality of these mechanical metamaterials.