  In nature, materials such as ferroelastics and multiferroics can switch their
microstructure in response to external stimuli, and this reconfiguration causes
a simultaneous modulation of its material properties. Rapid prototyping
technologies have enabled origami and kirigami-inspired architected materials
to provide a means for designing shape-shifting structures, and here we show
how multistable structures inspired by kirigami provide novel design criteria
for preparing mechanical metamaterials with tunable properties. By changing the
geometry of kirigami unit cells, we obtain multistable kirigami lattice
structures endowed with a bistable snap-through mechanism. We demonstrate the
precise control of material stiffness, along with the ability to tune this
property in situ by locally and reversibly switching the unit cell
configurations. We anticipate these mechanical metamaterials will provide a
platform to achieve in situ tunable electrical, optical, and mechanical
properties for a variety of applications in multifunctional materials,
two-dimensional materials, and soft robotics.
