Back from the dead. Seems like this stuff is making it's way into protection applications... For phones

http://www.thinkgeek.com/gadgets/cellphone/d5cd/

wonder if we'll see it more for moto gear or not

QuoteEnter the iBand, made of a magical non-Newtonian fluid called d30. What's that, you ask? To put it simply, a non-Newtonian fluid isn't held to one standard of viscosity. It does its own thing. d30 is a dilatant, which means its viscosity is stress-dependent. When it's not stressed, it's squishy. But when stressed, the apparent viscosity increases and the substance turns rock solid.

Sounds like a cornstarch-water solution.
http://www.scifun.org/homeexpts/lumpyliquids.htm

It essentially is except IIRC the first versions of it were powdered glass.

Quote from: somegirl on May 27, 2010, 06:17:39 PM
Sounds like a cornstarch-water solution.
http://www.scifun.org/homeexpts/lumpyliquids.htm

yep - we made that stuff with dome green food coloring too in elementary school and called it Oobleck after the stuff from a Dr Seuss book. And it's a great example of a non-Newtonian fluid, just like this d30 stuff. Obviouly not exactly the same since they have managed to mould or set the compound in something they can mould w/o it returning to a goopy fluid.

Either way - I'm still curious about the stuff.

You what I don't get about this? It's the complete opposite to what a helmet does; it becomes stiff when it hits something. Doesn't that just transmit all the force to the object in stead of absorbing it? It's probably great when you hit a sharp rock or something, then it spreads the impact over a larger area, but I don't think it reduces impact.

Quote from: He Man on October 19, 2009, 08:50:24 PM
who needs another video game system? 

That's what I thought 3DO:

Quote from: yuu on May 27, 2010, 12:42:24 PM
Back from the dead. Seems like this stuff is making it's way into protection applications... For phones

http://www.thinkgeek.com/gadgets/cellphone/d5cd/

wonder if we'll see it more for moto gear or not

I once saw this thing on the show Pitch Men before Billy Mays died where they had a material that was amazingly impact absorbing - the demonstration had Billy wrap his hand in what looked like a towl made of this stuff and then they drove over his hand with an SUV - his had was fine. So I always wondered why they didn't go that route for protective gear.

Quote from: IdZer0 on May 28, 2010, 06:03:51 AM
You what I don't get about this? It's the complete opposite to what a helmet does; it becomes stiff when it hits something. Doesn't that just transmit all the force to the object in stead of absorbing it? It's probably great when you hit a sharp rock or something, then it spreads the impact over a larger area, but I don't think it reduces impact.

Nope... it requires energy to realign the structure of the material - don't get something for nothing. So there's some energy absorbed there. Also, I'd expect that the material stiffens, but does not become hard like a helmets shell does. If it remains somewhat 'squishy' it will plastically deform, taking more energy.

Also, keep in mind that one of the tricks to protecting something is spreading the impact forces over a larger surface area. So an energy absorbing, semi-rigid  material would suit that task very well.

We can't reduce impact... that's a fixed amount. You hit something... now Newton is in charge. But, it's what we do with the forces at play taht counts.

I would imagine that the best applications would also include a bit of impact absorbing softer armor underneath.