University of Michigan flat-pack system with a uniformly thick structure can carry large loads and achieve multiple shapes and functions
The centuries-old practice of folding paper to create geometric versions of objects and animals has been a constant source of wonder, but efforts to design real life foldable origami-inspired structures have faltered because they are unable to support large loads.
Researchers at the University of Michigan claim to have cracked this conundrum by developing a modular structure with uniformly thick lockable panels, which can be adapted to different shapes and functions.
The lightweight system, explained in a paper published in the science journal Nature, could be used to build bridges, shelters, stages for live events, or even structures for space; a prototype 4m-long pedestrian bridge was able to support five people.
Evgueni Filipov, an associate professor of civil and environmental engineering, said: ‘These origami-inspired systems offer new philosophies for how we design and envision our built environment … they can enable adaptable buildings where floor plans, or the entire building, are reshaped, reconfigured and added-on for new use cases. The concept also enables de-constructability and long-term re-use of the same basic origami building blocks.’
Michigan researchers set out to tackle the challenge of existing origami structures being either foldable but too thin to carry large loads, or able to support large loads but not foldable. In addition, common solutions for civil applications tend to have a single kinematic path – chain of links – and therefore cannot be adapted into multiple configurations.
The origami ‘vertex’ MUTOIS (Modular and Uniformly Thick Origami-Inspired Structure) developed by the team comprises triangle-shaped panels of uniform thickness connected by rotational hinges. Once folds are locked into position, the system effectively transfers compression and tension forces without producing unwanted moments at connection points. Researchers say this contrasts with panels with non-uniform thickness, which can generate axial forces, resulting in moments that limit load-carrying performance.
The system can be configured to have any number of units in a longitudinal direction and either one, two, three or four in a horizontal direction, allowing the formation of structures with different aspect ratios, such as columns, trusses, and walls.
In tests, a prototype 4m-long origami bridge was able to support five people with little deformation, and a 1m-long column was capable of carrying over two tons of force. Uniform thickness also enabled improved bending capacity.
According to researchers, panels can be produced in a range of different materials and can have open or closed sides to fulfil different functions. For example, the pedestrian bridge uses solid panels at the base for comfortable walking and truss panels on the sides for efficient load-carrying.
Deploying the structure would involve locking the hinges and lifting the structure at specific locations by crane, which, say researchers, makes it suitable for civil applications because it avoids the use of special actuators, which increase construction cost.
Ongoing R&D will aim to explore the potential of ‘higher-order vertices’ with more links and the behaviours of more specialised connectors, such as self-latching connectors used in mechanical engineering, which could improve load-carrying performance and speed up assembly.
‘There is a need to explore how we can integrate these origami-inspired structures within building infrastructure and architecture,’ said Filipov. ‘It is unlikely we can use origami principles to design and construct an entire building, but for certain applications, such as walls, ceilings and facades, the deployability, modularity and adaptability of origami designs could be particularly useful.’