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The military may be turning to one of the sea’s most indestructible materials to make the next generation of helmets and body armor.

A research team from the Massachusetts Institute of Technology have explored using the superior strength of conch shells and reproducing that in engineered materials that could be used to provide customized protective headgear and body armor.

Conch shells have a unique configuration based on three different levels of hierarchy in the material’s internal structure that make it hard for tiny cracks to spread and enlarge. According to MIT graduate student Grace Gu, the structure of conch shells makes it 10 times tougher than nacre, commonly known as mother of pearl.

The researchers developed 3D printing technology with precisely controlled structures with exactly the same geometry as used in computer simulations.

“In the past, a lot of testing [of protective materials] was static testing,” Gu said in a statement. “But a lot of applications for military uses or sports involve highly dynamic loading,”

The material was tested in a drop tower that enabled the researchers to observe exactly how cracks appeared and spread or didn’t spread in the first instants after an impact. They also tested all three levels of structure with variations of the material with different levels of hierarchy.

The higher levels of hierarchy were introduced by incorporating smaller length-scale features into the composite, similar to the actual conch shell. The lower-level structures were significantly weaker than the highest levels, which consisted of the cross-lamellar features of natural conch shells.

The conch-like material proved to be 85 percent better at preventing crack expansion than the strongest base material and 70 percent better than a traditional fiber composite arrangement.

The researchers said each helmet could be tailored or personalized and the computer could optimize based on a scan of a person skull.

The study was published in Advanced Materials.

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