Finite Element Modelling of Different 2D Re Entrant Structures of Auxetic Materials

Abstract

Auxetic materials exhibit a unique characteristics when subjected to uniaxial loading. Various structures have been used to model these materials. Among most important auxetic structures, re-entrant structures are of interest in this present study. These structures have different shapes in which are known as lozenge grids, sinusoidal ligaments, square grids, double arrowhead, and structurally hexagonal re-entrant honeycomb could be named. In this paper, finite element approach for the abovementioned structures was employed to obtain basic mechanical properties including Poisson's ratio and elastic modulus. The study aims at investigating the effect of cross sectional geometry on mechanical properties. For each structure, three different cross sectional geometries were numerically examined. It is evident that mechanical properties of the material could be controlled by changing the geometry of the cross section. The primary outcome of the study is the design guideline on the effect of cross sectional geometry on mechanical properties of auxetic structures. In the present study, finite element technique has been employed in modelling these structures to represent the characteristic of the auxetic re-entrant structures. Five different shapes of 2D re-entrant structures have been considered to examine the influence of cross sectional geometry on the mechanical properties. It is evident that mechanical properties of auxetic material are controllable, thus facilitating the fabrication technique used in preparing samples in the laboratory.