Simulations of the properties of elongated hexagonal dodecahedron systems

Abstract

This study considers a 3D basic unit-cell proposed for auxetic and non-auxetic foams namely the elongated hexagonal dodecahedron deforming through changes in angle between its ligaments (idealised hinging model). This structure was studied in detail for the potential of exhibiting negative Poisson’s ratio and/or negative compressibility by means of a method based on standard force-field molecular modelling technique, termed as Empirical Modelling Using Dummy Atoms (EMUDA). The mechanical properties obtained from this method were then compared to a previously published analytical model of this structure [Grima J N, Caruana-Gauci R, Attard D, and Gatt R 2012, Proc. Roy. Soc. A 468 3121], and found to be in good agreement with each other. The results showed that this system can exhibit zero Poisson’s ratios in one of its planes and positive or negative Poisson’s ratios in other planes, depending on the geometry of the model. It was also shown that under certain conditions, negative linear and/or area compressibility was also exhibited.