We propose a novel two-dimensional hierarchical auxetic structure consisting of a porous medium in which a homogeneous matrix includes a rank-two set of cuts characterised by different scales. The six-fold symmetry of the perforations makes the medium isotropic in the plane. Remarkably, the mesoscale interaction between the first- and second-level cuts enables the attainment of a value of the Poisson's ratio close to the minimum reachable limit of -1. The effective properties of the hierarchical auxetic structure are determined numerically, considering both a unit cell with periodic boundary conditions and a finite structure containing a large number of repeating cells. Further, results of the numerical study are validated experimentally on a polymeric specimen with appropriately arranged rank-two cuts, tested under uniaxial tension. We envisage that the proposed hierarchical design can be useful in numerous engineering applications exploiting an extreme auxetic effect.
Hierarchical auxetic and isotropic porous medium with extremely negative Poisson's ratio / Morvaridi, M.; Carta, G.; Bosia, F.; Gliozzi, A. S.; Pugno, N. M.; Misseroni, D.; Brun, M.. - In: EXTREME MECHANICS LETTERS. - ISSN 2352-4316. - 48:(2021), p. 101405. [10.1016/j.eml.2021.101405]
|Titolo:||Hierarchical auxetic and isotropic porous medium with extremely negative Poisson's ratio|
|Data di pubblicazione:||2021|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.eml.2021.101405|
|Appare nelle tipologie:||1.1 Articolo in rivista|