Wrinkling, Folding and Crumpling of Thin Sheets – Narayanan Menon

Date: Thu. April 10th, 2008, 4:15 pm-5:15 pm
Location: Rockefeller 301

Under the action of external forces, thin sheets tend to bend out of plane rather than stretch. For weak forcing, this leads to the distinctive wrinkling instabilities that you see on your skin. When more strongly confined, sheets crumple, and condense stress into a network of ridges which confer rigidity on the bulk material. At even stronger forcing, ridges develop into plastic creases which lead to complex time-dependent mechanical properties. I will describe experiments that study various aspects of this progression of features, concentrating on the wrinkling patterns seen in ultra-thin polymeric sheets.