Cambridge, Mass. (CBS DC) — A new transparent armor inspired by the shells of a sea creature could provide protection for U.S. troops on the battlefield.
Researchers at the Massachusetts Institute of Technology have uncovered a lightweight and optically clear shell from the Placuna placenta mollusk that could be used as tough armor against bullets and other high-speed projectile threats to soldiers’ eyes and faces in combat.
Published in the journal Nature Materials on Mar. 30, MIT researchers Christine Ortiz and colleague Ling Li have detailed research of a “windowpane” oyster’s shell that uses long diamond-shaped crystals that can dissipate energy from penetrating forces nearly ten times better than calcite-based rocks such as limestone and chalk.
The researchers look to combine the strength of the shell structure with the transparent crystals that would not be as bulky as traditional armor such as Kevlar.
“We have long studied natural exoskeletons as inspiration for the development of advanced engineered protective systems,” study author Christine Ortiz, a materials scientist at the Massachusetts Institute of Technology, told Live Science. “About five years ago we started searching for natural armor systems, which were also optically clear,” Ortiz said. Transparent armor could serve in “soldier eye or face protection, windows and windshields, blast shields and combat vehicles.”
The researchers examined how the seashells’ diamond-shaped crystals join together to deflect penetration, yet are clear enough to read through.
Previous studies analyzed how mollusk and other shells could create armor, but the new MIT findings “is the first thorough study of a natural armor that resists mechanical penetration but is also optically clear,” Ortiz told Live Science. “We wanted to find out how the material resists penetration but also preserves this unique optical property.”
Microscopic denting showed that the mollusk shell deformed through a process called “twinning,” in which ceramic-like “crystals of calcite that were mirror images of each other formed around the penetration zone,” Live Science reports. This “twinning” process assisted in localizing damage and contained cracks from spreading throughout the shell.
The researchers look to combine the process of “twinning” and the shell’s structure to provide armor that could resist multiple hits.
“The findings in this work may provide design principles for synthetic engineering of lightweight structural materials with efficient energy dissipation,” Ortiz said. “We are continuing to study other armored species that exhibit semitransparent properties and intend to create a library of biological design principles.”