This user-friendly origami reimagines the emergency shelter

This user-friendly origami reimagines the emergency shelter

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He continued: “Many times, these things were built, but then they were left behind or destroyed.”

“This is a bridge between the mechanical principles (geometric shapes) of origami, and actually extends all the way to large structures. That is very rare.” Ann CichtersHe is an assistant professor of civil engineering at the University of Illinois-Urbana-Champaign, and he was not involved in this research. Sychterz specializes in the design of deployable shelters. She said: “These are essential steps for this work to truly enter real life.”

Bertoldi pointed out that we already have a famous deployable shelter: camping tents. Lightweight, compact tents make it easier for the backpack to travel through the wilderness. But it takes time to assemble a person into a closed space. You have to link the metal strips, pass them through the narrow holes in the fabric, and then fix them all in place.Set up a rebar-based structure a lot of Need more time and energy. The ideal emergency shelter can be quickly established when needed, but needs to be quickly dropped elsewhere.

Origami expandables alone suffer from similar problems. Going from 2D to 3D needs to tend to every fold. “The tricky part before origami is that you usually need to actuate each hinge, so actuation is really troublesome,” Bertoldi said.

The team used plastic sheets or cardboard to cover the face of the residence, but the magic of origami happened on the hinges. The face will not bend, so some effort must be made. The hinge can be a double-sided tape attached to a laser-cut cardboard, or a line that is mechanically scribed into a plastic sheet. This allows the structure to bend around itself for inflation and deflation. In order to make all the hinges swing into place automatically, her team decided that maybe they could use air pressure to inflate all the folds at once.

However, blowing air into an inflatable object is more like compressing a spring and then assembling a building. It is not bistable. Bertoldi said: “You compress it and deform it. However, once the load is removed, it will bounce back.” In other words, you can use the force exerted by air pressure to deform a stack of folded cardboard and turn it into An inflatable tent, but then you get stuck to ensure that air enters it, which of course excludes the possibility of opening the door.

Stability is about minimizing excess energy: a ball parked in a valley is more stable than a half ball on a steep hill. Bistability refers to designing a structure so that its energy barrier or locking it into an inflated or deflated state requires just the right amount of energy. The barrier must not be too high, otherwise it will not be possible to expand. But the obstacle can’t be too low, because a gust of wind will make it collapse: “It will tilt back and deflate,” Bertodi said.

She continued: “You need to design its energy barrier carefully.” “That’s most of the engineering design.”

Bertoldi’s team designed the structure using triangular faces. The energy barrier of each structure depends on how they shape these triangles, how they connect the geometry, and its building materials. First, they performed calculations, and then hand-made physical prototypes shaped like bows and explosions, repaired them with different building materials, and found the best location for the energy barrier. “It took us three years to really get to the bottom to figure out the geometric analysis and experimental part-how to build it,” Bertoldi said. Every decision from crease angle to panel material to hinge structure adds a variable that requires trial and error. “There are many failures. Many, many.”

Inflate (accelerate) the medium prototype of the emergency origami shelter.

Courtesy of David Melancon

Eventually, something was clicked. Literally.When pulling the folded structure to expand it, Bertodi recalled: “At a certain point, you will hear Click on. She compares this feeling to the feeling you get from the quick bracelets of the 1990s: “This is something you can really feel with your hands.” “

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