Computational design of two-phase auxetic structures

Optimization of structures with complex shapes is a big challenge for computational physics. Results of numerical calculations show that composite or sandwich panel structures have a great influence on their effective properties. This article presents numerical results of optimization of sandwich panel properties. Calculations were provided for a three-layer sandwich two-phase composite. Optimization techniques were used for minimization of the effective Poisson's ratio of the core. The resultant composite structure exhibits a negative Poisson's ratio (NPR), although all its constituents are characterized by positive values of the Poisson's ratio. The structure of the composite is completely filled with solid materials, hence no voids appear within its whole volume. To find a solution, the finite-element method combined with an optimization algorithm MMA (method of moving asymptotes) was used. For the purpose of analysis, the material parameters were written by means of the shape interpolation SIMP (solid isotropic material with penalization) scheme. (C) 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim