Chiral Metamaterial Predicted by Granular Micromechanics: Verified with 1D Example Synthesized using Additive Manufacturing

Granular micromechanics approach (GMA) provides a predictive theory for granular material behavior by connecting the grain-scale interactions to continuum models. Here we have used GMA to predict the closed-form expressions for elastic constants of macro-scale chiral granular metamaterial. It is shown that for macro-scale chirality, the grain-pair interactions must include coupling between normal and tangential deformations. We have designed such a grain-pair connection for physical realization and quantified with FE model. The verification of the prediction is then performed using a physical model of 1D bead string obtained by 3D printing. The behavior is also verified using a discrete model of 1D bead string.