Experimental realization of tunable Poisson's ratio in deployable origami metamaterials

TL;DR

This paper presents an innovative experimental setup to measure and demonstrate tunable Poisson's ratio in 2D origami metamaterials, confirming theoretical predictions and enabling exploration of their dynamic and static properties.

Contribution

The study introduces a novel experimental method with a Saint-Venant fixture for accurate Poisson's ratio measurement in deployable origami tessellations, validating tunability and sign switching capabilities.

Findings

Poisson's ratio sign can switch in Morph origami.

The setup accurately measures tunable Poisson's ratios.

Experimental results agree with theory and simulations.

Abstract

Origami metamaterials are known to display highly tunable Poisson's ratio values depending on their folded state. Most studies on the Poisson effects in deployable origami tessellations are restricted to theory and simulation. Experimental realization of the desired Poisson effects in origami metamaterials requires special attention to the boundary conditions to enable deployable nonlinear deformations that give rise to tunability. In this work, we present a novel experimental setup suitable to study the Poisson effects in 2D origami tessellations that undergo simultaneous deformations in both the applied and transverse directions. The setup comprises a gripping mechanism, which we call a Saint-Venant fixture, to eliminate Saint-Venant end effects during uniaxial testing experiment. Using this setup, we conduct Poisson's ratio measurements of the Morph origami pattern whose configuration space combines features of the Miura-ori and Eggbox parent patterns. We experimentally observe the Poisson's ratio sign switching capability of the Morph pattern, along with its ability to display either completely positive or completely negative values of Poisson's ratio by virtue of topological transformations. To demonstrate the versatility of the novel setup we also perform experiments on the standard Miura-ori and the standard Eggbox patterns. Our results demonstrate the agreement between the theory, the simulations, and the experiments on the Poisson's ratio measurement and its tunability in origami metamaterials. The proposed experimental technique can be adopted for investigating other tunable properties of origami metamaterials in static and in dynamic regimes, such as finite-strain Poisson's ratios, elastic thermal expansion, and wave propagation control.