Augmented snap-through instability of folded strips

TL;DR

This paper investigates how adding a single crease to folded strips enhances their snap-through behavior, increasing energy release and speed, with potential applications in soft robotics.

Contribution

It reveals that a single crease significantly alters snap-through dynamics, enabling control over energy release and speed in folded ribbons, supported by experiments, simulations, and theory.

Findings

Folded ribbons release more energy than unfolded strips.

Introducing a crease increases snapping speed.

Theoretical and numerical models explain the phenomena.

Abstract

Bistability and snap-through instabilities are central to various mechanisms in nature and engineering, enabling rapid movement and large shape changes with minimal energy input. These phenomena are easily demonstrated by bending a piece of paper into an arch and rotating its edges until snapping occurs. In this Letter, we show that introducing a single crease 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.