Modulation of multi-directional auxeticity in hybrid origami metamaterials

A novel origami metamaterial with programmable multi-directional auxeticity is proposed by hybridizing the concept of re-entrant honeycomb with the Miura pattern. Normal Miura-based origami metamaterials have been widely shown to exhibit negative in-plane Poisson's ratio. However, negative out-of-plane Poisson's ratio cannot be realized in these set of materials, essentially limiting their capability for prospective applications in many multi-functional devices and systems. Here we propose a hybrid Miura-based metamaterial that can show both in-plane and out-of-plane negative Poisson's ratios. More interestingly, we are able to program the Poisson's ratios to have mild to extreme auxeticity and map their mutual interaction as a function of the microstructural configuration. Besides the single-layer meta-sheets, we have shown that a class of multi-layer stacked metamaterial with uniform and graded configurations can be developed to achieve multi-objective functional goals. Theoretical and experimental analyses are combined in this paper to demonstrate the concepts of modulating multi-directional Poisson's ratios. The fundamental mechanics of the proposed origami based metamaterial being scale-independent, this novel class of deployable hybrid materials can be directly transferred for application in a range of milli-, micro-, and nanometer-size systems, essentially opening avenues for the design of energy absorbers, sensors, actuators, medical stents, catalysis, drug delivery systems, adaptive wings for next-generation of aircrafts and other deployable mechanical and electronic systems at multiple length-scales.