Origami is a delicate, intricate art form. In the eyes of University of Maine researchers and engineers, though, the ancient art of paper folding may be more than aesthetically pleasing — it can provide the structural basis for easy-to-deploy foldable shelters that can be used for disaster relief, temporary housing and more.
Deployable shelters need to be sturdy, easy to transport and simple to set up, whether they are used by soldiers or in emergency camps. Like origami, a foldable shelter is all about the act of folding. Varying the location of fold lines and vertices can create a multitude of patterns that fold into different shapes, from triangles to trapezoids.
Collapsible structures are usually thicker and stiffer than the thin paper used in origami. Partially or fully folding panels in these structures requires careful consideration of the hinge — how strong they are, how easy they are to rotate about their hinge lines without deforming during the transition process and whether they interfere with the other folding panels of the structure.
University of Maine mechanical engineering professor Masoud Rais-Rohani and graduate student Anthony Verzoni used mathematical and computer modeling to test the deployment of their origami-inspired shelter design concepts to make sure they were easy to set up, where the roof could actually be lifted by unfolding the walls. The engineers considered a number of variables, including how much force was required to unfold the shelter to a standing position, how having thicker walls would impact the shelter; and how the weight and composition of the panels would factor into deployment.
“The need for rapidly deployable shelters typically comes with quick delivery and setup requirements to accommodate urgent relief efforts,” Verzoni says. “Our preliminary focus was to utilize the principles of origami to create shelter systems that fold into compact shapes and unfold into large volumes that can house several individuals for various applications, all while limiting the required effort involved with deployment.”
Their models showed that it is possible to accommodate compound folding patterns in the flat-foldable, thick-walled, origami-inspired shelter. However, the load put on the structure to unfold it depends on where it is applied, and varies significantly during the transition process.
“We are essentially taking a mechanical system or mechanism and transforming it into a functional structure. Maximizing connectivity among the panels is a key design feature of these origami-inspired shelter concepts that would allow a room-size shelter to be set up in just a few minutes,” says Rais-Rohani.
The results reveal the importance of analyzing the full mechanics of opening and closing a foldable structure. The models will also inform future design decisions affecting the size, shape and erection load for similar shelters. Future research will look at the use of passive and active mechanical-assist systems to make deployment faster and easier, as well as ways to optimize the structure for use in both humanitarian and military applications.
“I hope our study will lead to a mass production and distribution of such deployable shelters for humanitarian relief around the world,” says Rais-Rohani.
The study appears in the December 2022 issue of Engineering Structures; it was published online in October 2022.