Scientists at a Polish company that produce body armor systems are working to implement a non-Newtonian liquid in their products.
The liquid is called Shear-Thickening Fluid (STF). STF does not conform to the model of Newtonian liquids, such as water, in which the force required to move the fluid faster must increase exponentially, and its resistance to flow changes according to temperature. Instead STF hardens upon impact at any temperature, providing protection from penetration by high-speed projectiles and additionally dispersing energy over a larger area.
“This viscosity increases thanks to the subordination of the particles in the liquid structure, therefore they form a barrier against an external penetrating factor,” said Karolina Olszewska, who performed tests on the STF for Moratex.
The exact composition of the STF is known only to Moratex and its inventors at the Military Institute of Armament Technology in Warsaw, but ballistic tests proved its resistance to a wide range of projectiles.
“We needed to find, design a liquid that functions both with projectiles hitting at the velocity of 450 meters per second and higher. We have succeeded,” said Deputy Director for Research at the Moratex institute, Marcin Struszczyk.
Struszczyk said the liquid’s stopping capability, combined with the lower indentation of its surface, provides a higher safety level for the user compared with traditional, mostly Kevlar-based, solutions.
“If a protective vest is fitted to the body, then a four centimeter deep deflection may cause injury to the sternum, sternum fracture, myocardial infarction, lethal damage to the spleen,” Struszczyk said.
“Thanks to the properties of the liquid, thanks to the proper formation of the insert, we eliminate one hundred percent of this threat because we have reduced the deflection from four centimeters to one centimeter.”
When hit by a high-speed projectile, a wide area of the STF hardens instantly, causing the usually massive energy to be dispersed away from the wearer’s internal organs.
Implementing the solution in body armor required designing special inserts, but the company says those are lighter than standard ballistic inserts and broader range of movement for their users in the police and military.
“The point is for them not to interfere, not change the way of movement, operation of such the product by the user, and at the same time increase their motor skills, increase effectiveness of their decision process and increase their possibilities during the mission at hand,” Struszczyk said.
The laboratory is also working on a magnetorheological fluid, which they hope can be also applied in their products.
According to the researchers, both liquids can find applications beyond body armor, such as in the production of professional sports inserts, and even entire outfits. Another use could be in car bumpers or road protective barriers.