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Technologists have harnessed the power of an ‘intelligent’ liquid that hardens when struck – and it promises to be a radical advance in body armour, giving frontline soldiers better protection against bullets and much more mobility in the harshest operating environments
Flexible friend on the front line
BAE Systems engineers are developing radical new 'Liquid Armour' that combines with more traditional protective materials such as Kevlar to give soldiers high levels of protection but much greater freedom of movement.
This innovative engineering technique takes advantage of the distinctive properties of ‘shear-thickening’ fluids, whose particles collide when disturbed, and can even lock together to form a solid barrier.
Kevlar armour is stiff, uncomfortable and can impede movement. Used to cover the torso it can be hot and heavy to wear, contributing to fatigue, particularly in extreme operating environments such as Afghanistan. But Kevlar combined with a counter-intuitive liquid can produce body armour that is 45% thinner, without any safety compromise.
The liquid armour technology is part of a project to create future body armour that gives soldiers greater ballistic protection and ease of movement in combat situations.
Stewart Penney, Head of Business Development for Design and Materials Technologies at BAE Systems, said:
“The technology is best explained by the example of stirring water with a spoon. In water you feel little resistance to the spoon, whereas with ‘liquid armour’, 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 traditional Kevlar is struck by a bullet, the impact area is small and shows a significant ‘dent’. It can save a soldier from death, but still causes considerable pain. When liquid armour is struck by a bullet the force is spread over a wider area and the depth of penetration is less because the reduced flow of the fluids restricts the motion of the fabric, dispersing the energy over a wider area. As a result, the material is less likely to distort than standard body armour – and after impact the liquid armour returns to a flexible form.
Trials conducted at BAE Systems’ Advanced Technology Centre have demonstrated the liquid armour’s properties. There are plans to further develop the liquid armour to create a lightweight version of the material and incorporate it into body armour systems.
And the team is looking at how the technology could be used in other sectors - there is business potential for a version that could be of interest to police forces and ambulance crews.
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