# AUXETIC MATERIAL DESIGN THROUGH STRUCTURAL OPTIMIZATION APPROACH

## Palavras-chave:

Parametric optimization, Auxetic structure, Negative Poisson’s ratio, Metamaterial## Resumo

Unlike conventional materials, an auxetic material has negative Poisson’s ratio, that is, it

increases the size of its cross-section when is under traction and decrease when is compressed. The

auxetic structural behavior can provide many benefits, since the structural material may acquire

notable mechanical properties, such as increased resistance to impact. Due to this improved impact

absorption capacity, the auxetic materials have great potential for use in the aerospace structures. In

this work, parametric optimization has been applied to develop a re-entrant structure (periodic cell)

that simulates the behavior of the auxetic material microstructure. Thus, the auxetic behavior arises

from the mechanism deformation of geometric configuration of the re-entrant structure. The main

motivation of this work is to contributes with a more systematic methodology to design of the auxetic

structures, make it independent of the designer expertise. Some 3D re-entrant auxetic structures of the

literature are adopted as initial design domain and a parametric optimization is carried out to obtain

optimized dimensional configurations for the geometry of the auxetic structure. Dimensional

parameters of the domain, such as angles, wall thickness, height, and width, are considered as design

variables in the optimization problem, in which the objective function is formulated to maximize de

behavior of the auxetic structure (negative Poisson’s ratio). Computational simulations of finite

element models are carried out to evaluate the optimized auxetic structures.