Directed Instability as a Mechanism for Fabricating Multistable Twisting Microstructure

Abstract

The study of multistable structures, particularly those that can twist, has attracted significant attention in recent years. This ability to transition between multiple stable geometries of these structures has paved the way for advances in diverse applications, such as morphing structures and robot actuation mechanisms. Conventional methods of designing and fabricating these structures often involve complex and resource‐intensive fabrication processes, which restrict their widespread adoption and limit their miniaturization. Here, we present a novel inflatable multistable twisting structure, based on helical folds of an elastic tube. Our fabrication approach utilizes directed mechanical instability as a method for a rapid fabrication, which is readily implemented at various length scales. We developed a theoretical model for the deformation of the bistable helical elements comprising the twisting structure, and compared it to experimental data. Furthermore, we demonstrate our fabrication methodology using a variety of polymers, including medical grade polymers, as well as various inner radii ranging from 5mm to 44μm and thicknesses of the tubes’ walls ranging from 250μm to 19μm .This article is protected by copyright. All rights reserved.