Effective properties and dynamic response of a sandwich panel made of two face sheets and auxetic core are analyzed in this study by computer simulations. The inner composite layer is made of a cellular auxetic structure immersed in a filler material of a given Poisson's ratio (filler material fills the voids in structure). Each cell is composed of an auxetic structure (re‐entrant honeycomb or rotating square), i.e., exhibiting negative Poisson's ratio without any filler. Influence of filler material on the effective properties of the sandwich panel is investigated. The proposed structure shows interesting structural characteristics and dynamic properties. Our results clearly show that it is possible to create auxetic sandwich panels made of two solid materials with positive Poisson's ratio. This is even possible if the filler material is nearly incompressible, but can move in out‐of‐plane direction. Moreover, effective Young's modulus of such sandwich panels becomes very large if the Poisson's ratio of the filler material tends to −1.

A sandwich-structured composite is a special class of composite materials that is fabricated by attaching two thin but stiff layers to a lightweight but thick core. Composites analyzed in this paper consist of two different materials: auxetic and structural steel. The optimization criterion is minimum compliance for the load case where the frame's top boundary is downward loaded. Outer layers are made of steel while the middle layer is twophase solid material composite. Only the middle layer is optimized by means of minimization of the objective function defined as the internal strain energy. In the first part of this paper we study the application of the solid isotropic material with penalization (SIMP) model to find the optimal distribution of a given amount of materials in sandwich-structured composite. In the second part we propose a multilayered composite structure in which internal layers surfaces are wavy. In both cases the total energy strain is analyzed.

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