CSAAW Workshop Special Guest Speaker will talk on paper crumpling dynamics

When describing the dynamics of a sheet of paper being crumpled one may be tempted to only take the elastic response of the thin sheet into account and consider only those deformations which minimize the elastic energy of the crumpled sheet. However, most materials yield and deform plastically, leaving permanent scars in the thin sheet. Indeed, the simple process of crumpling a sheet of paper with our hands results in a complex network of interconnected permanent creases of many sizes and orientations, along which the sheet preferentially bends. Thereby, history dependence is introduced into the system. I will present an experimental study of the dynamics of crumpling. Specifically, we investigate how a crease network evolves when a thin elastoplastic sheet is repeatedly crumpled, opened up and then re-crumpled. Is there a maximally crumpled state after which the sheet can be crumpled without further plastic deformations, or do creases and defects keep accumulating forever? Surprisingly, we find that much of the complex dynamics of the crease patterns can be captured using one simple global measure, which is independent of the crumpling history.