Stability of periodic porous structures

Abstract

In this chapter we focus on the mechanics of two-dimensional periodic elastomeric cellular structures and present numerical techniques for investigating their finite deformations. We then use them to show that in an elastic matrix with a periodic array of pores instabilities with wavelengths that are of the order of the size of the microstructure can be triggered. Interestingly, these instabilities can be utilized to design a novel class of responsive materials. Possible applications include materials with unusual properties such as negative Poisson's ratio, phononic and photonic switches and colorful and reconfigurable displays.

Designing recipes for auxetic behaviour of 2-d lattices

“…We find that through manipulation of the beam thickness and the length of the central section considered, the short wavelength deformation mode can be accessed at a lower critical load than the long wavelength mode. In contrast to methods based on Bloch-wave analysis [18][19][20][21], we present an analytical model for this finite sized lattice, including boundary effects, and show good agreement between our model and finite element simulations. This approach to calculating the buckling load of the lattice gives us an efficient method for the exploration of the design space.…”