Viscoelastic kirigami plates

Kirigami, the art of cutting papers, has been proven as a practical outline to fabricate flexible mechanical metamaterials with complex patterns of instability. In the absence of a well-controlled activation scheme, kirigami metamaterials may deform randomly into various 3D shapes while stretched. Here, we show how viscoelasticity can effectively control the direction of buckling and, therefore, the modes of buckling in such flat materials. Our approach enables reliable switching between various modes in response to the applied strain-rate. Our experimental study confirms the practicality of producing such “viscoelastic kirigami plates” using conventional additive manufacturing techniques. Furthermore, we show that phase-transformation via relaxation can be harnessed to conduct mechanical waves and dynamic pattern evolution in pre-stretched kirigami plates. Additionally, we developed a 1D dimensionless model that explains the requirement of soliton waves in the continuum limit. Our approach can serve as a basis for designing metamaterials with well-controlled and dynamic functionalities that inherit their properties from their viscoelastic kirigami backbone.