Shape Memory in Crumpled Thin Sheets

Abstract

Despite the seemingly trivial nature of crumpled paper, the crease structure produced in crumpled thin sheets represents a complex and intriguing disordered system. The bistability of the creases and nodes formed through crumpling allow for high shapeability in crumpled thin sheets. Here we experimentally study the retention of shape information in crumpled sheets, focusing on the factors that create and describe disordered crease networks. We follow the evolution of shape retention in repetitively crumpled elastoplastic sheets and show that shape memory is affected by both the number of crumples and the depth of crumple. We also show that the state variable for the total length of all creases in a crumpled sheet is insufficient to explain shape memory. Finally, we propose a variable to describe crease density that captures variances in shape memory for shallower depths of crumple and lays the groundwork for future work in the mechanisms and development of disordered crease networks.