As part of a project to create future body armor offering soldiers greater ballistics protection and ease of movement, scientists and engineers at BAE Systems have developed a liquid which hardens when struck. The technology, dubbed “liquid armor” by its developers, harnesses the unique properties of shear thickening or dilatant fluids that "lock" together when subjected to a force and is designed to enhance the existing energy absorbing properties of material structures like Kevlar.
Ceramic based armor plates used in current body armor systems to cover large areas of the torso are heavy and bulky, restricting movement and contributing to fatigue, particularly in harsh environments like Afghanistan. The liquid armor is designed to offer troops increased protection with reduced mass, wider area cover, greater maneuverability and easy integration with other systems. To this end, BAE says it can be integrated into standard Kevlar body armor to offer superior freedom of motion and a reduction in overall thickness of up to 45 percent.
“The technology is best explained by the example of stirring water with a spoon,” says Stewart Penney, Head of Business Development for Design and Materials Technologies at BAE Systems. “In water you feel little resistance to the spoon. Whereas with ‘liquid armor’, you would feel significant resistance as the elements in the fluid lock together. The faster you stir, the harder it gets, so when a projectile impacts the material at speed, it hardens very quickly and absorbs the impact energy.”
When integrated with Kevlar, the reduced flow of the fluids in the liquid armor restricts the motion of the fabric yarns in relation to each other, resulting in an increase in area over which the impact energy is dispersed. As a result, the material is also far less likely to distort than standard body armor, which generally bends inwards when a bullet strikes, preventing death, but causing considerable pain.
Trials conducted at BAE Systems’ Advanced Technology Centre in Filton have shown the liquid armor allows thinner than standard armor to withstand equivalent levels of forces. An early prototype of the technology has been demonstrated to the UK Ministry of Defence and in the future BAE Systems hope to further develop liquid armor to create a super lightweight version of the material and incorporate the technology into body armor systems.
The team at BAE Systems is considering applications of the technology beyond the military. Penney said: “In addition to increasing the ballistic performance of combat body armor there is potential for developing a version that could be of interest to police forces and ambulance crews.”
We wouldn’t mind getting our hands on BAE Systems’ liquid armor so we can whack our resident armor tester, Loz, with a saucepan and see how it stacks up against d3o’s motorcycle armor that also uses shear thickening material.