College project of my dreams

[Hatchett]

So in my university engineering course the class has been divided up into teams and each will design a 8" by 8", less than 1.5" square panel of lightweight composite using a variety of provided materials and whatever materials the class can think up. The finished product will be graded based on, first of all, its ability to withstand a direct hit from a "gas gun" firing a projectile of approximately 16 grams at 180m/s (I worked this out and I believe that's roughly 250 grains at 590fps, so I guess like an anemic .45 Colt or .44 Special load). Secondly it will be graded based on how damaged it is after stopping the hit, how light the material is, and how much it costs to make.

The class is designed to teach the students about composites, so we're supposed to make the panel out of at least two types of material. I believe certain materials like woven kevlar and fiberglass will be provided but probably not much. Other suggestions are fiberglass, ceramic tile, a various types of wood, styrofoam, and rubber. Basically, simple, obtainable, and overall cheap stuff.

The project hasn't been completely spelled out yet, so there may be more specifics, but in the meantime, anyone have any cool ideas? Anyone tried something similar themselves? I'll probably be the only one in the class who can rigorously test his team's prototypes on the shooting range.

 

[Sans Authoritas]

Lexan. Layers. Cut it into squares, (rounded edges), laminate layers together with spray adhesive. .25'' of duct tape around it all. : )

If you can get some boron carbide, well, more power to you.

Leaf spring steel (from the axle suspension) will stop just about anything, too. I popped a piece with a .303 Brit at one at 200 yards once. (Safely angled, of course: do not try at home.) It looked like someone had scuffed it.

-Sans Authoritas

 

[highorder]

Everything you could want is here:

www.mcmaster.com

down at the bottom on the right is the Raw Materials section. You can have kevlar, Dural armor plate, Lexan (polycarbonate), etc. Have fun!

 

[Guitargod1985]

Get some aerogel

 

[Bendutro]

I'm graduating with my BSME in 46 days. I've done wet-layups with carbon-kevlar composites too.

The key is energy dissipation. Aramid fiber is AMAZINGLY tough, not just tensile strength, but all out toughness. Besides material properties, pay very close attention to the resin ratio and orientation angles of your layers.

Sounds like a cool project. What school do you go to and what sector do you want to work in after graduation?

 

[cleardiddion]

Aerogel, I got to see a presentation on that stuff.
The ability to catch particles of astroids in deep space is a feat to behold indeed

 

[bnkrazy]

You need a bulletproof hoodie.

 

[bogie]

Call Solutia (formerly the Monsanto Chemical Group). The word to use is "Saflex."

Or, if you want to get moderately low-tech...

Epoxy aluminum to fiber to aluminum. Or if you wanna get a little odd, sandwich hardened steel between the epoxy layers.

If I had 1.5" thickness to work with, I could stop a .50BMG...

 

[CWL]

Polycarbonate. The commercial name is Lexan but it is just PC.

PC is commonly used to make bullet-proof 'glass', it is also relatively cheap and easy to find.

 

[Conqueror]

get some 1/4" lexan and layer it with kevlar and carbon fiber. Something like:

kevlar-carbon-lexan-carbon-kevlar.

Then layer those panels together to reach your desired thickness.

 

[dtown240]

16 grams. 590 fps......hmmm My first guess is that they're using marbles out of a PVC tube using compressed air or CO2.

Regardless of the projectile, good luck.

 

[Cyclimus]

+1 on www.mcmaster.com - most raw materials are in stock and can ship the day they are ordered.

 

[MrPeter]

If you really want to impress your friends, the cheapest and most easily made bullet proof material that I know of is Pykrete.
You can make it for 100% free, and it has a ton of uses.
You could possibly even make your own Navy out of it!

I can't vouch for how lightweight it will be though.

 

[Funderb]

lexan layers with something shock absorbing between them.
If you can stop the first layer from shattering, unlikely with lexan, the absorbing layers will create a negative elastic impact, thus reducing the shock very very much.