1 Chiral Metamaterial Predicted by Granular Micromechanics: Verified with 2 1D Example Synthesized using Additive Manufacturing 3 4 5 Anil Misra1*, Nima Nejadsadeghi 2, Michele De Angelo 1,3, Luca Placidi 4 6 7 8 1Civil, Environmental and Architectural Engineering Department, 9 University of Kansas, 1530 W. 15th Street, Learned Hall, Lawrence, KS 66045-7609. 10 2Mechanical Engineering Department, 11 University of Kansas, 1530 W. 15th Street, Learned Hall, Lawrence, KS 66045-7609. 12 3Dipartimento di Ingegneria Civile, Edile-Architettura e Ambientale, Università degli Studi 13 dellAquila, Via Giovanni Gronchi 18 - Zona industriale di Pile, 67100 LAquila, Italy 14 3International Telematic University Uninettuno, 15 C. so Vittorio Emanuele II 39, 00186 Rome, Italy 16 *corresponding author: Ph: (785) 864-1750, Fax: (785) 864-5631, Email:
[email protected] 17 18 19 20 21 22 23 Continuum Mechanics and Thermodynamics 24 25 26 27 28 Abstract 29 Granular micromechanics approach (GMA) provides a predictive theory for granular material 30 behavior by connecting the grain-scale interactions to continuum models. Here we have used 31 GMA to predict the closed-form expressions for elastic constants of macro-scale chiral granular 32 metamaterial. It is shown that for macro-scale chirality, the grain-pair interactions must include 33 coupling between normal and tangential deformations. We have designed such a grain-pair 34 connection for physical realization and quantified with FE model. The verification of the 35 prediction is then performed using a physical model of 1D bead string obtained by 3D printing. 36 The behavior is also verified using a discrete model of 1D bead string.