Augmented snap-through instability of folded strips

Abstract

Bistability and snap-through instabilities are central to various mechanisms in nature and engineering, enabling rapid movement and significant shape changes with minimal energy input. These phenomena are readily demonstrated by bending an elastic strip into an arch and rotating its edges until snapping occurs. In this article, we show that introducing a fold in such a strip significantly alters its snapping properties. In particular, folded ribbons release much more energy than the regular, unfolded case, leading to faster snapping speeds. Through numerical simulations and theory, we rationalize our experimental observations. We leverage our findings to program the snapping behavior of folded ribbons, demonstrating how our results could find practical applications, e.g., in soft robotics.