Self-locking degree-4 vertex origami structures

• Published in: Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences Vol. 472; no. 2195; p. 20160682
• Main Authors: Fang, Hongbin, Li, Suyi, Wang, K. W.
• Format: Journal Article
• Language: English
• Published: England The Royal Society 01.11.2016
• Subjects: Facet-Binding; Mechanical Metamaterial; Piecewise Stiffness; Programmable Structures; mechanical metamaterial; facet-binding; programmable structures; piecewise stiffness
• ISSN: 1364-5021; 1471-2946
• DOI: 10.1098/rspa.2016.0682

A generic degree-4 vertex (4-vertex) origami possesses one continuous degree-of-freedom for rigid folding, and this folding process can be stopped when two of its facets bind together. Such facet-binding will induce self-locking so that the overall structure stays at a pre-specified configuration without additional locking elements or actuators. Self-locking offers many promising properties, such as programmable deformation ranges and piecewise stiffness jumps, that could significantly advance many adaptive structural systems. However, despite its excellent potential, the origami self-locking features have not been well studied, understood, and used. To advance the state of the art, this research conducts a comprehensive investigation on the principles of achieving and harnessing self-locking in 4-vertex origami structures. Especially, for the first time, this study expands the 4-vertex structure construction from single-component to dual-component designs and investigates their self-locking behaviours. By exploiting various tessellation designs, this research discovers that the dual-component designs offer the origami structures with extraordinary attributes that the single-component structures do not have, which include the existence of flat-folded locking planes, programmable locking points and deformability. Finally, proof-of-concept experiments investigate how self-locking can effectively induce piecewise stiffness jumps. The results of this research provide new scientific knowledge and a systematic framework for the design, analysis and utilization of self-locking origami structures for many potential engineering applications.