Heuristic molecular modelling of quasi-isotropic auxetic metamaterials under large deformations

A two-dimensional molecular model is presented for the elastic non-linear modelling and design of meta-materials. The fundamental unit-cell, based on a heuristic molecule (HM) approach, composed atoms that interact through centred non-centred spring-based bonds. kinematics formulation allows to consider large displacements finite strains while specific topology HM can be parametrized modify shape rigid size frame indifferent provides remarkable quasi-isotropic response both deviatoric volumetric deformation modes. At macro-scale, relationship with different continuum materials given standard isotropic Cauchy up an Cosserat solid. Evidence interest as calculation tool provided by studying auxetic subjected non-homogeneous field, well foams under deformations. Aside numerical agreement, it highlighted how tailoring effective approximate geometric effects occur at finer scales foams. In perspective, we address exotic mechanical properties HM, together assumed physical-driven framework, foster engineering application new