Bistable auxetics

A bistable auxetic metamaterial (BAM) subject to tension


Auxetic materials become thicker rather than thinner when stretched, exhibiting an unusual negative
Poisson’s ratio well suited for designing shape transforming metamaterials. Many auxetic designs,
however, are often monostable and cannot maintain the transformed shape upon load removal. Our research involves a class of switchable architected materials exhibiting simultaneous auxeticity and structural bistability by using kirigami. The material concept is experimentally realized by perforating various cut motifs into a sheet, thus creating a network of rotating units connected with compliant hinges. The metamaterial performance is then assessed through mechanical testing and accurately predicted by a coherent set of finite element simulations.

Relevant publications

Shang X, Liu L, Rafsanjani A, Pasini D, Durable Bistable Auxetics Made of Rigid SolidsJournal of Materials Research – Focus Issue: Architected Materials, Vol. 33 (3), pp. 300-308, 2018. 

Rafsanjani A, Pasini D, Bistable Auxetic Mechanical Metamaterials Inspired by Ancient Geometric MotifsExtreme Mechanics Letters, Vol 9(2), 291-296 2016.