Forget about Kevlar: Liquid Body Armor Hardens on Impact | Hacker News Reader

Forget about Kevlar: Liquid Body Armor Hardens on Impact

news.discovery.com

48 pointsvoodoochilo21 comments

Non-Newtonian fluidics is at work here [0].

If you want to try it at home, mix cornstash with water (roughly 2 to 1) and create an Oobleck [1]. Guaranteed success with kids (and adults who remained young at heart).

[0] http://en.wikipedia.org/wiki/Non-newtonian_fluid

[1] http://en.wikipedia.org/wiki/Non-newtonian_fluid#Oobleck , http://www.google.fr/url?sa=t&rct=j&q=&esrc=s... , http://www.google.fr/url?sa=t&rct=j&q=&esrc=s... , http://www.google.fr/url?sa=t&rct=j&q=&esrc=s...

"Cornstarch in water" was my first thought when reading this title, thanks to 7th grade science class.

Same here, but thanks to Mythbusters in my case.

Another example of a non-newtonian fluid (Except, in this case, shear-thinning instead of shear-thickening) would be ketchup.

It explains some kitchen accidents...

* Tilts the bottle

It doesn't come out.

* Taps the bottom

Still nothing.

* Tap tap tap...

Nope.

* TAP!

Ketchup ocean in my plate...

Good... the slow blade penetrates the shield... but look down. We'd have joined each other in death. However, you did seem to finally get in the mood.

For the Dune reference! :)

I don't think kevlar protects against blades either

It's actually quite old, the idea of using liquids as a body armor. The problem with implementation was the weight of the liquids.

From this article, it has appeared that the problem was solved, since they mention that is a lot lighter and provides more freedom of movement.

http://news.discovery.com/tech/winter-olympics-body-armor.ht...

Being used for skiers and mentions its use in body armor at the time (2010). I'm pretty sure I read an earlier article than that one as well, perhaps from 2006 or so but I can't find it.

I can't tell from this new article if they've improved the fluid, or the method of application to kevlar is the novel part.

I have a few-years-old pair of d3o motorcycling gloves; from the company that made the skier armor. It's not interwoven with kevlar, and I haven't "tested" it; but they have been around for quite a while.

Maybe you're thinking of D3o (http://www.d3o.com/), which has been around since 2005 or so.

first i saw about non newtonian liquids was a british science entertainment show.

and about a year afterwards they began talking about using the same as armour. just stuck in my mind as the kids show came first.

from 2003. http://www.youtube.com/watch?v=JkS1ymQ73oc&feature=relat...

from 2004. http://www.technovelgy.com/ct/science-fiction-news.asp?newsn...

Question: If it hardens when it is disturbed, does it mean that it hardens if the wearer runs, for example? This would mean you still can't properly armor joints...

I think the more force (or acceleration?) it undergoes the more it hardens. So hopefully running wouldn't affect it, but a fast moving projectile would.

Have a good day.

500+MPH impacts are vary different than simple joint movements. Think of it like this, if you slowly move your hand though water you don't feel any resistance, jump off a bridge and hit it at 100MPH and the stuff might as well be concrete.

Shear thickening fluids have a non-linear relationship between shear rate and shear stress. Schematically, it's the green line in this graph [1]. By choosing your material carefully, you can minimize shear stress at 'running' speeds, and then sharply ramp it up to protect against faster projectiles.

[1] http://en.wikipedia.org/wiki/File:Shear_rate_vs._Shear_stres...

Thanks for all the answers everyone, I get it now :)

The article does not show what the name of this new product is that I can find.

D3o has been out for a while and some of the videos are really impressive.

https://en.wikipedia.org/wiki/D3o

Reminds me of the armor in Dune.

I remember a Larry Niven fan in high school excitedly explaining the concept of armor that hardens on impact. http://www.technovelgy.com/ct/content.asp?Bnum=927

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