Exotic mechanical properties enabled by countersnapping instabilities

From an umbrella flipping inside out during a gust of wind to a slender stick bowing when compressed, mechanical instabilities are often seen as undesirable. However, they can also be leveraged, as illustrated by the snapping-based prey capture strategies of the Venus flytrap and mantis shrimp. Inspired by these observations, researchers have started to harness such nonlinear effects to design materials with exotic and programmable functions. Here, we expand this repertoire by experimentally demonstrating countersnapping, where a combination of geometrically nonlinear building blocks cooperate to suddenly contract when increasingly tensioned. We demonstrate that this behavior unlocks exotic mechanical and dynamical behavior, potentially useful for metamaterials, sensors, and smart structures.