Exploring the dependencies of Poisson's ratio in auxetic structures

Abstract Auxetic materials are mostly known for their negative Poisson's ratio, a parameter used to describe the deformation behavior of structures. This ratio serves a similar role as a material constant, detailing behavior on a microscopic scale. However, the deformation behavior of complex auxetic structures cannot be described completely using the classical Poisson's ratio approach. While it may suffice to describe auxetic behavior in foams or crystals, it fails for larger scales like the auxetic lattice structures, discussed in this study. To address this limitation, an extension to the classical Poisson's ratio is proposed to better describe the behavior of such structures. The developed method shows the different dependencies, namely the directional dependency, the frequency dependency and the position dependency of auxetic unit cells.