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Chain mail-inspired fabric supports 50 times its own weight

Posted: News,   : 2021-08-14 02:37:45 pm
By: : Pascaline NYIRABUHORO

Engineers at California Institute of Technology (Caltech) and the Nanyang Technological University (NTU) in Singapore teamed up to develop a chain mail-inspired fabric that transforms from a fluid malleable material into a solid protective material when under pressure, a press statement reveals. The material could be used for a host of potentially life changing applications, including as smart fabric for exoskeletons, for a cast that becomes more or less rigid when needed to facilitate the healing of an injury, and as a deployable bridge that could be thrown over an obstacle and stiffened so that people can walk across with ease. The team set out "to create a fabric that goes from soft and foldable to rigid and load-bearing in a controllable way," said Chiara Daraio, a corresponding author on the team's study, which is published in the journal Nature. The researchers developed the material via a combination of trial and error with different material types and computer simulations of the different patterns and their properties. They compare the tough state of their material to the way a pack of rice can be extremely hard when vacuum sealed – once opened, however, it flows out of the bag like a fluid. The key to the team's material was controlling this process.

Below is a demonstration of the soft, unjammed material being struck by a metal ball.

Testing the impact resistance of the material when unjammed (soft). Photo credit: Caltech.

Testing the impact resistance of the material when jammed (rigid). Photo credit: Caltech.

When stiffened, the material has the potential to act as a sturdy bridge. Photo credit: Caltech.

Here is the same material, struck by the same ball but in its jammed state – it is clearly more impact-resistant and much sturdier.

The material developed by the group of international researchers is composed of hundreds of 3D-printed hollow, 8-sided triangular shapes that can be made out of plastic or aluminum. By jamming these triangular shapes together using a plastic vacuum casing, the team was able to demonstrate that their material could support a load more than 50 times the fabrics' own weight. "These fabrics have potential applications in smart wearable equipment: when unjammed, they are lightweight, compliant, and comfortable to wear; after the jamming transition, they become a supportive and protective layer on the wearer's body," said Caltech postdoctoral researcher Yifan Wang, who is now an assistant professor at NTU. The researchers also say they could run a cable through a lightweight roll of the material that's been suspended over a river or gorge, and then tighten the cables to jam the pieces together and make them tough. "Think of these cables like the drawstrings on a hoodie," Wang said. Small strips of the chain mail-like material could also be used as a form of back support or as a load-bearing strip for exoskeleton users, or to improve haptic feedback technologies for virtual reality sets. The material, therefore, could play a large role in military, medical, and even home electronics innovations of the future.

This article originally appeared in Interesting Engineering of Aug 13, 2021.


Nature. (2021.08.11). The smart chain mail fabric that can stiffen on demand. YouTube URL:watch?v=S2n9VJrra3g.

Wang Y, Li L, Hofmann D, Andrade JE, Daraio C. 2021. Structured fabrics with tunable mechanical properties. Nature. 596, 238–243. DOI:10.1038/s41586-021-03698-7.

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