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Foldable structures are widely used in engineering because they can transform from compact flat sheets into larger three-dimensional forms. But most existing designs face a tradeoff: structures that are smooth and curved tend to remain soft and unstable, while rigid load-bearing systems usually rely on angular, faceted geometries that limit adaptability and comfort.
Researchers have now developed a new origami-inspired structure designed to overcome that limitation. Using a specialized crease pattern combined with adjustable internal cables, the system can transform flat sheets into smooth curved shells that switch between flexible and rigid states without changing materials or overall shape.
The design is based on what researchers describe as a “doubly curved” origami shell. Unlike conventional origami structures that form sharp geometric folds, the new pattern combines curved and straight crease lines to create continuous surfaces resembling spheres, toruses, or vase-like forms. According to TechXplore, the geometry is calculated using differential geometry models and numerical optimization techniques that determine exactly how the sheet must fold to achieve the desired 3D shape.
Once folded, the structure can be mechanically tuned using embedded tendon-like cables threaded through key points in the shell. Tightening the cables increases stiffness and allows the structure to resist twisting and bending forces, while loosening them returns the system to a softer, more flexible state. Importantly, the transition happens without altering the structure’s geometry or replacing components.
Researchers physically built the structures by laser-cutting and folding paperboard sheets before integrating the internal tensioning cables. Simulations and mechanical analysis confirmed that the folding motions remained feasible and that the resulting surfaces preserved smooth curvature while supporting load-bearing behavior.
From a defense and aerospace perspective, reconfigurable load-bearing structures could support deployable shelters, adaptive robotics, compact transport systems, or lightweight space structures that need to remain flexible during deployment but rigid during operation. The ability to tune stiffness through geometry alone may also reduce reliance on heavier mechanical systems or complex smart materials.
The work reflects a broader trend in metamaterials research, where geometry itself becomes a functional engineering tool rather than simply a structural feature. By combining mathematical modeling with physical folding mechanics, the approach points toward future structures that can dynamically adapt shape and rigidity depending on operational needs.
The research was published here.
