Shape Selection and Multi-stability in Helical Ribbons

Helical structures, ubiquitous in nature, have inspired design and manufacturing of helical devices with applications in nanoelecromechanical systems, morphing structures, optoelectronics, microrobotics and drug delivery devices. Meanwhile, multi-stable structures have attracted increasing attention for their applications in bio-inspired robots and deployable aerospace components. Here we show that mechanical anisotropy and geometric nonlinearity can lead to novel selection principle of shape and multi-stability in helical ribbons, with table-top experiments performed to demonstrate the working principle. Our work will promote understanding of large deformation and instability of thin objects, and serve as a tool in developing functional structures for broad applications. PACS numbers: 46.25.-y