Tunable Auxetic Mechanical Metamaterials with “Arch‐Shaped” Units

Abstract

Rationally designed artificial materials providing unusual mechanical properties are attracting continuous interests due to the wide technological applications such as metamaterials for flexible electron and biomedical devices. A variety of natural biological tissues exhibit “J‐shaped” stress–strain behavior, so a challenge and interesting subject is to offer protection to electronics from a certain strain that may induce potential device failures. In the current letter, a novel porous auxetic metamaterial with “J‐shaped” stress–strain curve is designed and a method for tuning Poisson's ratio and stress–strain curve is illustrated. Experimental tests, numerical simulations, and analytical modeling are implemented to quantify the evolution of the Poisson's ratio and stress–strain curve, revealing the underlying mechanisms responsible for the unusual behavior. The structure simultaneously shows elastic wave bandgaps at certain frequency, which can finally extend to three‐dimension. The designed structural metamaterial has potential for applications in tissue engineering, bio‐medical devices, and comfortable integration of stretchable electronics with biological tissues, it also provides a new routine to design architected metamaterial systems exhibiting desired properties.