Twist-Induced Snapping in a Bent Elastic Rod and Ribbon

Tomohiko G. Sano, Hirofumi Wada

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Snapping of a slender structure is utilized in a wide range of natural and manmade systems, mostly to achieve rapid movement without relying on musclelike elements. Although several mechanisms for elastic energy storage and rapid release have been studied in detail, a general understanding of the approach to design such a kinetic system is a key challenge in mechanics. Here we study a twist-driven buckling and fast flip dynamics of a geometrically constrained ribbon by combining experiments, numerical simulations, and an analytical theory. We identify two distinct types of shape transitions: A narrow ribbon snaps, and a wide ribbon forms a pair of localized helices. We construct a phase diagram and explain the origin of the boundary, which is determined largely by the geometry. We quantify the effects of gravity and clarify the timescale dictating the rapid flipping. Our study reveals the unique role of geometric twist-bend coupling in the fast dynamics of a thin constrained structure, which has implications for a wide range of biophysical and applied physical problems.

Original languageEnglish
Article number114301
JournalPhysical review letters
Issue number11
Publication statusPublished - 2019 Mar 22
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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