A novel foldable structure design method offers significant potential for applications in soft robotics, flexible electronics, and deployable space structures.
From DNA and proteins to artificial structures inspired by origami, folding inspires scientific exploration.
From the natural folding of DNA and proteins to artificial foldable structures inspired by origami, the folding of slender structures provides fertile ground for scientific exploration. Traditional foldable structures typically offer a single folding mode, which has limitations. Continuous folding processes are slow, while abrupt folding caused by elastic snapping involves strong vibrations. Achieving tunable folding behaviour and performance in a single structure has always been challenging.
Dr Mingchao Liu from the University of Birmingham and Dr Weicheng Huang from Newcastle University have proposed a groundbreaking foldable structure design method to address this challenge in their research, titled "Integration of kinks and creases enables tunable folding in meta-ribbon," which was recently published in Matter.
Their method, which introduces in-plane kinks and out-of-plane creases into elastic strips to create a tunable foldable structure called a meta-ribbon, enables transitions between continuous and snapping folding modes, a feature not found in traditional foldable structures.
Together with collaborators Dr Tian Yu from the Southern University of Science and Technology, Professor K. Jimmy Hsia from Nanyang Technological University and Professor Sigrid Adriaenssens from Princeton University, the research systematically studied the nonlinear folding process of annular elastic ribbons through discrete models, theoretical analysis, and physical experiments. The group found that in-plane kinks and out-of-plane creases cause continuous and abrupt snapping folding governed by supercritical and subcritical bifurcation. Integrating kinks and creases into the same strip allows for tunable folding behaviour, transitioning from continuous to snapping, or vice versa, by strategically engineering the in-plane and out-of-plane angles guided by the constructed energy map. Dynamic analysis showed continuous folding avoids vibrations, while abrupt snapping folding does not.
Furthermore, the study revealed that due to breaking rotational symmetry during angle changes, meta-ribbons formed buckled structures with multiple stable states. A meta-ribbon with eight in-plane/out-of-plane creases exhibited three stable states, and displacement loading could achieve transitions between these states. This method offers new possibilities for creating adaptable structures.
Dr Mingchao Liu commented: "This innovation opens new pathways for creating adaptive foldable structures with wide-ranging applications, from robotics to space technology. The research demonstrates the proposed method's effectiveness, laying a solid foundation for developing functional structures, from fundamental physical mechanism analysis to novel intelligent structure design and practical engineering applications."
Assistant Professor
Staff profile for Dr Mingchao Liu, University of Birmingham
