A 2D microstructure with auxetic out-of-plane behavior and non-auxetic in-plane behavior. (2nd November 2017)

• Record Type: Journal Article
• Authors: Davini, Cesare; Favata, Antonino; Micheletti, Andrea; Paroni, Roberto
• Is Part Of: Smart materials and structures. Volume 26:Number 12(2017:Dec.)
• Publication Date: 2017-11-02
• Subjects: auxetic behavior -- metamaterials -- bending Poisson coefficient -- synclastic surfaces; Smart materials -- Periodicals; Strucural design -- Periodicals; 620.11
• DOI: 10.1088/1361-665X/aa9091
• Languages: English
• ISSNs: 0964-1726

Abstract

Abstract: Customarily, in-plane auxeticity and synclastic bending behavior (i.e. out-of-plane auxeticity) are not independent, being the latter a manifestation of the former. Basically, this is a feature of three-dimensional bodies. At variance, two-dimensional bodies have more freedom to deform than three-dimensional ones. Here, we exploit this peculiarity and propose a two-dimensional honeycomb microstructure with out-of-plane auxetic behavior opposite to the in-plane one. With a suitable choice of the lattice constitutive parameters, in its continuum description such a structure can achieve the whole range of values for the bending Poisson coefficient, while retaining a membranal Poisson coefficient equal to 1. In particular, this structure can reach the extreme values, −1 and +1, of the bending Poisson coefficient. Analytical calculations are supported by numerical simulations, showing the accuracy of the continuum formulas in predicting the response of the discrete structure.