Elastic properties of a material composed of alternating layers of negative and positive Poissonʹs ratio

The theory of elasticity predicts a variety of phenomena associated with solids that possess a negative Poissonʹs ratio. The fabrication of metamaterials with a ‘designed’ microstructure that exhibit a Poissonʹs ratio approaching the thermodynamic limits of 1/2 and −1 increases the likelihood of realising these phenomena for applications. In this work, we investigate the properties of a layered composite, with alternating layers of materials with negative and positive Poissonʹs ratio approaching the thermodynamic limits. Using the finite element method to simulate uniaxial loading and indentation of a free standing composite, we observed an increase in the resistance to mechanical deformation above the average value of the two materials. Even though the greatest increase in stiffness is gained as the thermodynamic limits are approached, a significant amount of added stiffness can be attained, provided that the Youngʹs modulus of the negative Poissonʹs ratio material is not less than that of the positive Poissonʹs ratio material.