Self-Folding Metasheets: The Optimal Pattern of Strain of Miura-Ori Folded State

Abstract

Self-folding origami has emerged as a tool to make functional objects in material science. The common idea is to pattern a sheet with creases and activate them to have the object fold spontaneously into a desired configuration. This article shows that collinear quadrilateral metasheets are able to fold into the Miura-Ori configuration, if we only impose strain on part of their creases. In this study, we define and determine the optimal pattern of strain (OPS) on a collinear quadrilateral metasheet, that is the pattern of minimum "functional" creases with which the self-folding metasheet can fold into Miura-Ori state stably. By comparing the energy evolution along the folding pathway of each possible folded state under OPS, we conclude that the energy predominance of the desired Miura-Ori pathway during the initial period of time accounts for why the OPS works. Furthermore, we measure the projected force of the OPS on the intial flat metasheet and give insights on how to determine the OPS using only local information of the initial flat state.