Materials with negative Poisson ratios are known to have high shear rigidities – a useful property for many types of structural and functional materials. To improve upon relatively low Young’s modulus of existing auxetics, one may consider embedding such components in an elastic material...

Exact formulation for calculating effective elastic moduli of an isotropic two-phase disordered composite with ellipsoidal or elliptic inclusions are given in the mean-field approximation, which yields simple analytic expansions of effective Poisson ratio and Young's modulus to second order in...