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Equally probable positive and negative Poisson's ratios in disordered planar systems.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Verstreken, Christophe M 
Chalut, Kevin J 
Blumenfeld, Raphael 

Abstract

Auxetic materials, characterised by a negative Poisson's ratio, have properties that are different from most conventional materials. These are a result of the constraints on the kinematics of the material's basic structural components, and have important technological implications. Models of these materials have been studied extensively, but theoretical descriptions have remained largely limited to materials with an ordered microstructure. Here we investigate whether negative Poisson's ratios can arise spontaneously in disordered systems. To this end, we develop a quantitative description of the structure in systems of connected basic elements, which enables us to analyse the local and global responses to small external tensile forces. We find that the Poisson's ratios in these disordered systems are equally likely to be positive or negative on both the element and system scales. Separating the strain into translational, rotational and expansive components, we find that the translational strains of neighbouring basic structural elements are positively correlated, while their rotations are negatively correlated. There is no correlation in this type of system between the local auxeticity and local structural characteristics. Our results suggest that auxeticity is more common in disordered structures than the ubiquity of positive Poisson's ratios in macroscopic materials would suggest.

Description

Keywords

0912 Materials Engineering

Journal Title

Soft Matter

Conference Name

Journal ISSN

1744-683X
1744-6848

Volume Title

14

Publisher

Royal Society of Chemistry (RSC)
Sponsorship
Medical Research Council (MC_PC_12009)
This work was supported by the Engineering and Physical Sciences Research Council (C. M. V.), and the UK Medical Research Council and Wellcome Trust (K. J. C.).