On the effect of the poisson’s ratio on samples subjected to shearing

Abstract

The effect of shearing on finite-sized auxetic and non-auxetic samples was examined through finite element simulations. It was shown that when shear was applied in a manner representative of a common shear-testing setup, which is not dissimilar to the situation encountered in sports applications, auxetics manifested very different characteristics compared to their non-auxetic counterparts; with very pronounced edge effects. These included extensive lateral expansion of the samples and the formation of non-insignificant concave creases on their exposed lateral faces. It was shown that these creases became even more pronounced when the samples were subjected to combined shear and compressive loads and need to be taken into consideration when assessing the suitability, or otherwise, of auxetics for practical applications where shear loading may be present to a certain extent.

Auxetics and FEA: Modern Materials Driven by Modern Simulation Methods

“…Another limitation of FEA is that the quality of the simulations typically relies on the properties of the intrinsic materials. In some cases, these are not easy to define and the material properties are unmeasured (as is the case with the simulations of systems made from hypothetical auxetic materials, e.g., [13,93]) or are entered in an over simplified way, such as by assuming that the material is behaving linearly, thereby mitigating against high computational costs. Such assumptions may reduce the applicability and accuracy of the simulated characteristics, which calls for further validation.…”

“…Moreover, FEA offers the advantage that it is not limited to the conventional test parameters and can accurately and reliably simulate real-life scenarios even with unconventional parameters, such as an isotropic negative Poisson's ratio. This is particularly useful in the field of auxetics to study the behaviour of these unconventional materials in practical applications (e.g., shearing [93] or pressing [13]). Despite the lack of real materials with such properties, FEA enables us to anticipate their behaviour.…”