Help: "Bulletproof" Vest Questions!

[RstyShcklfrd]

Okay, let me start with why I'm asking this. I'm having to write a mock research proposal for one of my classes and am needing some of this information to supplement my paper. Basically what I need to know is why rifle rounds pierce through kevlar, as opposed to say a 9mm bullet. I have being googling this for a while, and have yet to find any definite answers to my question. I want to know whether or not it's the actual kinetic energy of the rounds that allow it to pierce through kevlar, or if it is the shape. If anyone has any real life experience with this or links to experimental data it would be greatly appreciated.

 

[Texan2]

Rifle 3000+fps
Handgun 1000fps

 

[RstyShcklfrd]

So you're saying that the energy of the round is what is piercing the kevlar? If that were the case then one can make the assumption that if a material were developed that could effectively absorb and disperse the energy then rifle rounds would be less likely to pierce body armor?

 

[RetArmySgt]

The rifle rounds are travailing too fast for the Kevlar to dissipate its energy.

 

[RetArmySgt]

So you're saying that the energy of the round is what is piercing the kevlar? If that were the case then one can make the assumption that if a material were developed that could effectively absorb and disperse the energy then rifle rounds would be less likely to pierce body armor?

There are several types of armor out there that can stop rifles rounds. Usually it is in the form of plates added to a Kevlar vest.

 

[RstyShcklfrd]

There are several types of armor out there that can stop rifles rounds. Usually it is in the form of plates added to a Kevlar vest.

I knew that, and this is where the topic of my paper comes into play. I just wanted to make sure that the most significant part of penetration of body armor is due to the energy of the bullet, and not that a 5.56 round is sharper than a 9mm.

 

[Texan2]

It is not soley one or the other. There is body armor that can stop rifle rounds as well.

 

[RstyShcklfrd]

Let me try to clarify.

Kevlar cannot stop rifle rounds due to the energy of the rounds(Which is what I'm asking). If say, Kevlar were draped over a material that COULD effectively absorb and disperse the energy, theoretically, could it stop the rifle rounds?

 

[Younggun]

I imagine that if it were the shape of the bullet it would pass through the kevlar without tearing the fibers and only spreading them. So Goin with energy.

Kinda funny that a broadhead arrow would probably go right through also.

 

[RstyShcklfrd]

Fantastic. This is what I was hoping for.

 

[M. Sage]

It's size vs energy to some degree. Smaller diameters are going to focus the force down on a smaller area, making it more likely that the bullet will go through the armor. Of course, it's still going to hurt you, even if it does get stopped.

Construction of the bullet can also have an effect - kevlar is going to have trouble stopping bullets made of solid brass, for example. Unjacketed lead is going to be much easier to stop because it will deform more on impact.

Yes, you can layer kevlar up to the point that it's rifle-resistant, but it would be stupid thick.

 

[M. Sage]

This page has a bit of info. BulletProofME.com Body Armor - Quick Answers to FAQs Turns out they're located in Austin.

 

[RstyShcklfrd]

Well the idea of my paper is focused on the development of a material that can absorb high levels of energy while maintaining flexibility. What I'm thinking is if you had some layers of Kevlar on top of this material, a bullet would hit it and not penetrate due to the material absorbing all of the kinetic energy. This is just an undergraduate level chemistry course, so it doesn't have to be TOO entirely realistic.

 

[M. Sage]

Well the idea of my paper is focused on the development of a material that can absorb high levels of energy while maintaining flexibility. What I'm thinking is if you had some layers of Kevlar on top of this material, a bullet would hit it and not penetrate due to the material absorbing all of the kinetic energy. This is just an undergraduate level chemistry course, so it doesn't have to be TOO entirely realistic.

Oh, they already developed that. I'll have to find it. It's a treatment that can be applied to any fabric. The molecules align and it becomes rigid when you apply a high amount of force to the stuff. Let me look for it...

 

[M. Sage]

Here you go: Liquid Armor: Science Videos - Science News - ScienCentral

 

[RstyShcklfrd]

My material is way different. I'm using aerogels. Aerogels will absorb kinetic energy and collapse. A significant part of the kinetic energy would not be transfered to the user, so they wouldn't feel that shock resulting in less harm ex. broken ribs, bruising, etc.

 

[M. Sage]

More like a trauma plate? BulletProofME.com Body Armor - Accessories for Concealable Vests

 

[M. Sage]

More interesting stuff on that nano armor thingy. Shear Thickening Fluid (STF) Fabric:Images and Videos

 

[M. Sage]

Question: Is an aerogel really that suitable? I thought they were brittle... Something that can absorb the impact and spring back to take another hit seems more appropriate. What was that gel-like stuff they developed a few years ago? They were dropping light bulbs and eggs off a roof onto the stuff to demo it...

 

[RstyShcklfrd]

Question: Is an aerogel really that suitable? I thought they were brittle... Something that can absorb the impact and spring back to take another hit seems more appropriate. What was that gel-like stuff they developed a few years ago? They were dropping light bulbs and eggs off a roof onto the stuff to demo it...

You're right, but aerogels can absorb lots of energy with respect to their weight. This is just an assignment for my inorganic chemistry class where we are suppose to write a research proposal. The chemistry behind it doesn't have to be 100% possible. My idea was that a combination of kevlar along with my proposed aerogel would make for better body armor when compared to layers and layers of kevlar with a ceramic plate. If the aerogel was able to absorb a significant portion of the energy, the user wouldn't be harmed as badly when hit by the bullet. Also, if the aerogel was able to replace the need for heavy ceramic plates and excessive layers of kevlar, flexibility would be increased and weight would be decreased.

And as for "something that can absorb the impact and spring back to take another hit", I believe ceramic plates would not be able to withstand multiple hits from rifle rounds either. But if the user can take a shot from a bullet without being knocked down, they would be able to respond faster.

Just an idea though. Lol