The vest, itself is lined with various types of fabrics in
various weaves in layers to spread the impact energy over a larger surface area
and increase the time of the impulse (I = F * t). The most popular fabric is Kevlar 29, a
polymer aramid fiber developed by DuPont and used in high strength
applications. Other materials include Dyneema, Gold Flex, Spectra and the
infamous Dragon Skin. These materials in application can generally stop up to a
pistol round successfully.
The ceramic plates are used as an additional layer of
protection added in as a layer of the vest to protect from high energy rifle
rounds. These plates are composed of either a ceramic (boron carbide or silicon
carbide ceramic) with a spall protection liner on the back.
These two systems combined can prevent serious injuries from
most common small arms and rifle cartridges in the world today. The issue is
that these systems are extremely heavy and currently require tradeoffs between
a higher level of protection and weight and flexibility. Modern ceramic plates
themselves weigh anywhere from 3 to 7 pounds each (Small to Extra Large). With
a full set of plates and a vest, the user will be carrying about 30 pounds of
weight in addition to what else is required to safely work.
Body armor coverage is also an issue. Standard ballistic
plates used for the US Army provide around a 10”x12” area of protection for the
front and rear and 6”x8”. This means that any sort of round directed in any
other area that is more powerful than the fabric will penetrate the armor.
While attachments exist for the groin, shoulders and neck on military grade
vests, these can only provide the level of protection that the fabric can.
Another issue is being bulletproof versus stab-proof. The
initial viewing of this argument may lead to the assumption that if it’s
bulletproof that it must be stab proof. This is not the case because of the
weave of the fabric used. As seen in the following video (http://www.youtube.com/watch?v=rYIWfn2Jz2g&feature=related)
the Kevlar weave “windows” and allows the improvised blade to penetrate with
little resistance. The solution to this is shown is a sheer thickening fluid,
and when applied as seen in the video drastically changes the way that the
Kevlar interacts with the point.
This type of materials development can potentially lead to
lighter, more flexible and more protective body armor for the future.
I saw this article on "HowStuffWorks"
ReplyDeleteThe Kevlar needs to be soaked in these two fluids that allow the vest to be liquid like in movement, until something strikes the vest directly. Shear-Thickening Fluid is the material that helps allow this to happen, the fluid is a colloid, which means that the particles have repelling forces. When a large force acts upon them the repelling forces are overwhelmed and they stick together forming masses called hydroclusters. The other fluid used in body armor is made of silica particles suspended in polyethylene glycol, its a form of nanotechnology because the particles sizes are so small.
Kind of cool how the some of the strongest material for body armor we have is made strong because of liquid.
http://science.howstuffworks.com/liquid-body-armor1.htm
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ReplyDeleteI think this is an interesting topic. I'm sure the US military is developing body armor technology but I'm not sure how many of their inventions and any other info they would actually release to the general public. I'm sure they are very top secret in their development, so it might be hard to present an entirely updated report on this technology, but I could be wrong.
ReplyDeleteIt is interesting that a body armor have the risk of being stabbed through. This example shows the importance of combine different materials. It remains me of the invention of strong glass. It was because a chemist let a solution coated on a container and dropped it by mistake. He find out it is not as easy to break as a glass.
ReplyDelete