Slashdot Mirror
Flexible Body Armor
dotmax writes "One item to pop out of the Turin Winter Olympics is the use of flexible body armor. Similar to silly putty, this shear rate material is flexible under normal load and hardens under impact. Sounds expensive, but could offer some great alternatives for traditional hard shelled impact gear in active sports and military applications."
Looks like they use a Non-Newtonian fluid, that's the type of material that has these properties.
This was one of the cooler demonstration in my HS chemistry class, the teacher made up a big batch of water + corn starch, and was playing with it like mud, squishing it around and whatnot. Then he beat the hell out of it, and it just sat there and didn't splash, it looked (and sounded) like it was a solid sheet. It was odd to see something that was very dynamic under low force, but static under high force.
It's like a seatbelt, if you yank it hard it locks up, but if you pull gently it will extend.
...and frankly, this flexible armor sounds great. The reason you want some kind of protection is that you (sometimes in speed events, very often in slalom) run into gates (the plastic poles stuck in the snow that you have to turn around) with various parts of your body. Since you are going fast, and you are wearing a thin aerodynamic racing suit, it hurts like hell. So, if you don't feel like getting hurt, you strap on some plastic shin and arm guards, sort of like an Ancient Greek warrior with his greaves. Anyway, these plastic guards really are not the ideal solution. They chafe (since you are strapping them on tight, and the muscles and skin under the straps are constantly moving). They limit your motions quite a bit. They are, frankly, uncomfortable. And if you are doing speed events, they kill your aerodynamics.
So, as far as I am concerned, flexible armor is totally the way to go. Hopefully FIS won't ban it.
But I don't quite follow. The grandparent poster was skeptical about the value of flexible armor over parts that should never bend. If your shin is bending significantly, your shin's probably broken.
Close your left hand over your right lower arm. Now turn move your hand left and right, up and down, flex the muscles... that thing moves a lot. The shin likewise has muscles and two bones in it. Apparently the sporters like this flexible thing better than rigid protectors, so it seems to help.
Why the poster calls this "body armor" i'm not sure though, according to TFA this is purely about shin and arm protection, the areas that get into contact with the sticks during slalom skiing.
I believe posters are recognized by their sig. So I made one.
John Brunner's "Stand On Zanzibar", 1968 Hugo Award winner. The item was called "karatands". A soft glove-like material until hardening on impact.
This is a truly oustanding book that should be digested by geeks everywhere. The political and social points are even more relevant today that 30+ years ago.
Well PopSci also had an article about it (the print version, it should be on the web version in a few days). Apparently they are putting it into helmets it allows for a flexable beanie type hat to become a hardhat when nessesary. According to the article it wouldn't be good enough for a motocycle helmet but would be perfect for speeds skating for example.
It isn't primarily the hardness but the stiffness that prevents blunt impact injury in armor design. The impulse is distributed over a wide area so that the peak force is less than the threshold for bruising. Crumpling is used in secondary foam in helmets (which does not contact the wearer directly). In helmets, the outer shell, the resilient inner foam and the skull provide the force-spreading function. Crumpling is not relevant to armor design since the purpose is not to absorb the energy but to distribute it, and crumpling material would be far too bulky for ski armor anyway.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
These suits provide protective padding for RACERS so they don't suffer bruises or breaks when the hit the gates. These suits are NOT for crashes.
I am a competitive alpine ski racer. Watch the slalom (SL) events in the Olympics and you will see that every athlete wears hard protective equipment on his poles (to protect his hands), his shins, and usually on his head. This is because the tightest, shortest, fastest line down the course involves literally running over the gate. The athlete generally "cross-blocks" the gate, meaning his feet are on the correct side of the pole and angled outward, while his body is upright with the pole directly in his path; he simultaneously hits the gate with the protector on the front of his pole ("pole guards") and his shin guards. Furthermore, he's wearing a lycra speed suit that's got padding in several key areas including the front of the forearms, the back of the thighs, the deltoid area of the upper back, and the bicep area of the upper arm. This is to provide protection for when the athlete performs an "inside clear" instead of a cross-block, or if he loses his rhythm or something else that causes him to hit a gate where he's not wearing molded plastic armor.
Or you could have just read the article.
Intercarve Networks, LLC