Programmable Hierarchical Kirigami Through Controlling Local Cuts

Abstract

Kirigami, through introducing cuts into a thin sheet, can greatly improve the stretchability of structures and also generate complex patterns, showing potentials in various applications. Interestingly, even with the same cutting pattern, the mechanical response of kirigami metamaterials can exhibit significant differences depending on the cutting angles in respect to the loading direction. In this work, we investigate the structural deformation of kirigami metamaterials with square domains and varied cutting angles of 0° and 45°. We further introduce a second level of cutting on the basis of the first cutting pattern. By combining experiments and finite element simulations, it is found that, compared to the commonly used 0° cuts, the two-level kirigami metamaterials with 45° cuts exhibit a unique alternating arrangement phenomenon of expanded/unexpanded states in the loading process, which also results in distinct stress–strain response. Through tuning the cutting patterns of metamaterials with 45° cuts, precise control of the rotation of the kirigami unit is realized, leading to kirigami metamaterials with encryption properties. The current work demonstrates the programmability of structural deformation in hierarchical kirigami metamaterials through controlling the local cutting modes.