| Wed August 22nd 2018 16:00 – 17:00 ZH286 | Seminar | The deformation of floating, elastic sheets: Finn Box |
Details:Floating, elastic sheets are ubiquitous in nature, and their deformation is of interest over a range of scales. At very large scales, floating ice sheets are often used in cold regions as construction platforms for transport routes, airfields and offshore oil exploration sites.Whereas, at the other end of the length-scale spectrum, the material properties of ultra-thin polymer films can be determined from the readily observable wrinkle patterns that form when floating films are subject to a localized force either from the capillary pressure of a fluid droplet or an imposed displacement from an indenter. In both cases, the applied load is supported by a combination of the stresses within the sheet and the hydrostatic pressure in the liquid. In this talk, I will highlight the physical features that distinguish small scales from large scales and will discuss which material we feel when we poke a sheet that coats a liquid layer. I will then describe an experimental investigation of impact of a sphere onto an ultra-thin, floating elastic sheet and, in doing so, explore features of dynamic wrinkling that are qualitatively different to those seen in quasi-static wrinkling experiments. In particular, our experiment shows that the wrinkles coarsen dynamically, rather than exhibiting the refinement that is expected quasi-statically; a difference which is due to the inhibiting effect of the inertia of the underlying fluid. | ||
