72th Annual Meeting of the APS Division of Fluid Dynamics (November 23, 2019 — November 26, 2019)

V0027: The fast & the flexible: dynamic buckling of slender structures induced by the bursting of a soap film

  • Finn Box, Mathematical Institute, University of Oxford
  • Ousmane Kodio, Mathematical Institute, University of Oxford
  • Doireann O'Kiely, Mathematical Institute, University of Oxford
  • Alain Goriely, Mathematical Institute, University of Oxford
  • Dominic Vella, Mathematical Institute, University of Oxford
DOI: https://doi.org/10.1103/APS.DFD.2019.GFM.V0027

In this video we explore the fast buckling of flexible elastic structures. We float elastic bands in a soap film, harnessing the surface tension of the soap film to impart a tension on the band. Initially, elastic bands are held in equilibrium, with soap film on both sides. But, after bursting the outer soap film the surface tension of the inner soap film causes the elastic band to collapse. Here the surface tension mimics an external pressurization, so the system is analogous to a thin-walled elastic cylinder subject to an externally applied pressure — a subject of considerable engineering interest. For example, if thin-walled pipes in a boiler or vacuum tank were to rapidly lose internal pressurisation, they may collapse in a similar way. At a much larger scale, if a submarine were to spring a leak and rapidly collapse under the hydrostatic pressure of the surrounding fluid, it could also buckle dynamically as it collapses in on itself. Our results do not provide a means of preventing collapse, but instead show that different buckling patterns can be achieved by modifying the rate of loading. This provides a new route to selecting different morphologies, or failure modes, in a particular system.

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