Idea: Kevlar gunshot injuries solution

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In summary, the conversation discussed the possibility of using solid substances that harden proportionally with kinetic energy to create flexible yet protective body armor. Non-Newtonian fluids were suggested as a potential solution, but it was noted that they may not be able to withstand the energy of bullet impacts in a wearable form. Other materials, such as Hadfield steel and backing materials like rubber or gel, were also mentioned but may not be practical due to weight or cost. The conversation concluded with anecdotal experiences of using various materials to reinforce body armor.
  • #1
AtotehZ
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Hey guys,

When you are shot with a gun you get hurt even if you're wearing kevlar. In some cases you even break ribs or puncture a lung.

Are there no solid substances out there that hardens proportionally with the kinetic energy that is applied?

If that was woven into the vest it wouldn't impair movement since the kinetic energy applied to the fabric is relatively low with regular movement, but a bullet would make it harden and prevent the full force of the impact from affecting a small area on the body.

Wouldn't this be possible?
 
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  • #2
Hardness is a complicated property that is dependent on many factors, such as elasticity, plasticity, brittleness, and toughness. See a more in depth article here: http://en.wikipedia.org/wiki/Hardness

To add to that, stopping a bullet takes more than just hardness, and body armor must be carefully designed so that the force and energy of the impact is spread out over a large enough area to avoid causing the armor to shatter/fail or the wearer from taking severe injury. Some very hard materials are simply too brittle and would shatter instead of deforming, which would only pose more of a hazard to the wearer. In addition, the weight and bulk of the armor is a very high point of consideration. Metal plates several inches thick would provide ample protection from small arms and rifle fire, but would be far too heavy and bulky to wear.

Needless to say, research in improving body armor is ongoing.
 
  • #3
1. There are attempts at using shear thickening materials (non-Newtonian fluids) as a body armor.

2. No matter how hard the body armor is, conservation of kinetic energy and momentum of the projectile/bullet means you will be - at best - heavily shaken. That always hurts.
 
  • #4
AtotehZ said:
Are there no solid substances out there that hardens proportionally with the kinetic energy that is applied?

If that was woven into the vest it wouldn't impair movement since the kinetic energy applied to the fabric is relatively low with regular movement, but a bullet would make it harden and prevent the full force of the impact from affecting a small area on the body.

Wouldn't this be possible?

Welcome to PF AtotehZ

As stated by Drakkith and Borek's posts, you are looking for Non-Newtonian fluids and there are attempts to make armor with these just that most cannot withstand the Energies of the smallest handgun bullets in a wearable form and size.

Gelatin is "close" to a Non-Newtonian and you could search the abuse a 5lbs Gummy-bear gets on Youtube (I think it's posted by Taofledermaus). But for a full torso armor it would weight too much.

Hadfield Steel hardens under stress, although there is no definite proportionality to it and it does not make it bulletproof in thin-sheet form. British Brodie Helmets were made of it and were good enough for shrapnel shells. Of course it is not flexible as this property is probably what you are looking for.

Vests are backed against deformation with rubber, plastic composites, titanium or ceramics and depending on how they are build they can be flexible. See Dragon armor and Scale armor. As far as I know only the vests which offer low-grade protection against handgun rounds are left without backing.
 
  • #5
Lok said:
Welcome to PF AtotehZ

As stated by Drakkith and Borek's posts, you are looking for Non-Newtonian fluids and there are attempts to make armor with these just that most cannot withstand the Energies of the smallest handgun bullets in a wearable form and size.

Gelatin is "close" to a Non-Newtonian and you could search the abuse a 5lbs Gummy-bear gets on Youtube (I think it's posted by Taofledermaus). But for a full torso armor it would weight too much.

Hadfield Steel hardens under stress, although there is no definite proportionality to it and it does not make it bulletproof in thin-sheet form. British Brodie Helmets were made of it and were good enough for shrapnel shells. Of course it is not flexible as this property is probably what you are looking for.

Vests are backed against deformation with rubber, plastic composites, titanium or ceramics and depending on how they are build they can be flexible. See Dragon armor and Scale armor. As far as I know only the vests which offer low-grade protection against handgun rounds are left without backing.

Thanks,

Those were the vests I had in mind. Some investigators wear these very thin vests. My point was exactly as Drakkith mentions, to make the energy dissipate over a larger area because of the hardening property, but preserve maximum movement and thinness. What I had in mind was backing of thin kevlar with something like a non-Newtonian substance.
 
  • #6
AtotehZ said:
Those were the vests I had in mind. Some investigators wear these very thin vests. My point was exactly as Drakkith mentions, to make the energy dissipate over a larger area because of the hardening property, but preserve maximum movement and thinness. What I had in mind was backing of thin kevlar with something like a non-Newtonian substance.

Non-Newtoinian fluids are as they are called fluids, the main characteristic of these is low to insignificant mechanical properties. You will need a thick amount to get an effect.

It is easier to just distance the non-backed vest form the body by soft spacers (PU rubberized foam), or why not with inflated bicycle tire tubes. Thus the Kevlar absorbs more of the energy before reaching the body by forcing the bullet to pull a lot of fabric with it until it touches the body. Like the Japanese Horo (arrow catcher).
 
  • #7
Stretch Armstrong in your pocket

When I was a young Marine, we played around with shooting at body armor with different objects behind the vest. We were always surprised at what worked and didn't work. Like using a fire ax to get through bullet-proof glass...worked the best.

With body armor, there was a difference, of course, between flak jackets and actual bullet-proof vests. Metal plates in front of the vests worked best, but the weight and lack of flexibility were unpleasant. Different types of rubber, gel soles, etc... were played with. As I recall, we had a lot of success with several different types of Stretch Armstrong toys.

If you recall, you could slowly squish and stretch a Stretch Armstrong doll if you did so slowly. If you tried to do so rapidly or quickly, the material acted very rigid and hard. Maybe we could get Mattel to make a Stretch Armstrong body armor vest liner? Or give a bunch of Stretch Armstrong dolls to the troops to carry in their pockets. Might relieve a lot of the boredom also.
 
  • #8
Distance the non-backed vest from the body

Lok said:
Non-Newtoinian fluids are as they are called fluids, the main characteristic of these is low to insignificant mechanical properties. You will need a thick amount to get an effect.

It is easier to just distance the non-backed vest form the body by soft spacers (PU rubberized foam), or why not with inflated bicycle tire tubes. Thus the Kevlar absorbs more of the energy before reaching the body by forcing the bullet to pull a lot of fabric with it until it touches the body. Like the Japanese Horo (arrow catcher).

NOTE: In the early days when the military did not supply bullet-proof jackets, some of the guys purchased their own, and would wear this over the flak jacket. Several guys got shot and had real good results. This would confirm your thought about distance the non-backed vest from the body.
 
  • #9
Just a guess here, wouldn't u make the armor break in only the parts you want to fail; like if you could weave thin, semi-brittle steal or aluminum cable that is meant to shatter, into the Kevlar. or maybe thin ceramic tiles.
 
  • #10
BigDogDaddyD said:
NOTE: In the early days when the military did not supply bullet-proof jackets, some of the guys purchased their own, and would wear this over the flak jacket. Several guys got shot and had real good results. This would confirm your thought about distance the non-backed vest from the body.

I remember the USMC M1955 vests the marines had on the ship in the 70's, we had a few for the ships security alert force.

I think the fluid is called STF but you still need some sort of trauma plate to spread the force from a bullet.
http://www.ccm.udel.edu/STF/media.html [Broken]
 
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  • #11
BigDogDaddyD said:
This would confirm your thought about distance the non-backed vest from the body.
I see the problem as being the spreading of bullet energy. The energy of impact radiates in a widening cone from the point of impact, which would suggest you must intercept the bullet as far from the body as possible to spread that energy over as wide an area as possible.

A Kevlar vest concentrates the remaining bullet energy by wrapping the bullet in a tight Kevlar conical well. That energy needs time to fall through tension in the Kevlar before remnant point energy reaches the body.
 
  • #12
Look at the law of impulse

Someone in the above replies talked about distance between the body and the outsite of the Kevlar vest. Remember there is the so called impulse, defined as the product of velocity and mass of the bullet, which is equal to the produced force by time during bullet impact. Studying this equation, you will see, the shorter the impact time the larger the impact force to the body of the person is. This means, if there is zero way to decelerate the bullet speed, the force to the person would get infinit high. This gives the answer to your idea of having a hard vest: it will shock the person the more the harder the protection vest is. To reduce this shock impact to the person, you need to have a minimum decelerating way for the bullet. By the way, the working force at impact can be calculated by measuring the duration of impact, when you know the bullet weight and speed.
 
  • #13
AtotehZ said:
Hey guys,

When you are shot with a gun you get hurt even if you're wearing kevlar. In some cases you even break ribs or puncture a lung.

Are there no solid substances out there that hardens proportionally with the kinetic energy that is applied?

If that was woven into the vest it wouldn't impair movement since the kinetic energy applied to the fabric is relatively low with regular movement, but a bullet would make it harden and prevent the full force of the impact from affecting a small area on the body.

Wouldn't this be possible?

A link from a few years ago.

That one's liquid, not solid. Not sure how much this really matters, seems like IED's were always more on your mind when I was in. AK rounds made plates even iffy as far as survival went, but I do remember one guy getting shot in the back. Broke his back but he didn't die.
 
  • #14
Student100 said:
A link from a few years ago.

That one's liquid, not solid. Not sure how much this really matters, seems like IED's were always more on your mind when I was in. AK rounds made plates even iffy as far as survival went, but I do remember one guy getting shot in the back. Broke his back but he didn't die.

Nice link and great concept, yet after 2 years I did not hear of a positive result.

The main problem is with the so called "locking" of the ST-fluids particles, it will never compare in strength to bonding, as for a liquid to be liquid you need low molecular mass or low inter-molecular attraction. Even if you interlock the particles they will be either too small to add up or too "slippery" and in both cases their yield strength will not amount to much.

Let's try some articles:
http://trj.sagepub.com/content/82/6/542.full.pdf+html
http://link.springer.com/article/10.1023/A:1024424200221#page-1
While STF does decrease penetration depth, it seems to be due to added weight rather than STF properties. In the second article we can observe that 4 layers of kevlar with STF weigh as much as 16 layers of kevlar (although 16 leyers were not tested) and penetration depth was mostly due to added weight. 4 layers can prevent full penetration yet to decrease depth added mass helps.
 
  • #15
"Student100" you got it: "...broke his back..."
As above explained from "ovacs", you need do have decelerating distance for the bullet to be stoped. Here is an example: bullet speed 500m/s and bullet weight 1gr and 2ms stopping time, then the resulting beat to person is 250kg, engough to kill.
By the way, forget all the different kind of liquids which are discussed above. We are working with loose fibres and may come up soon with remarkable results.
 
  • #16
A good link on a STF (not the best but good enough) shot.


vs.


Warning, a 5lb Gummy bear was hurt during the making of the second video.
Enjoy.
 

1. What is Kevlar and how does it work to prevent gunshot injuries?

Kevlar is a strong and durable synthetic material that is commonly used in bulletproof vests and other protective gear. It is made up of long-chain polymer molecules that are arranged in a strong and flexible pattern. When a bullet hits Kevlar, the energy from the impact is dispersed over a large area, preventing the bullet from penetrating the material and causing injury.

2. How effective is Kevlar in preventing gunshot injuries?

Kevlar is highly effective in preventing gunshot injuries. It is able to stop bullets from most handguns and small firearms, and can even provide protection against some high-powered rifles. However, it is important to note that the effectiveness of Kevlar can vary depending on the type of bullet and the velocity at which it is fired.

3. Can Kevlar be used to prevent injuries from other types of weapons?

While Kevlar is primarily known for its use in preventing gunshot injuries, it can also provide protection against other types of weapons, such as knives and shrapnel. However, the level of protection may vary depending on the force and angle of the impact.

4. Are there any limitations or drawbacks to using Kevlar for preventing gunshot injuries?

One of the main limitations of Kevlar is that it is only effective against projectiles that are traveling at high speeds. This means that it may not provide adequate protection against low-velocity weapons, such as pellet guns. Additionally, Kevlar is not completely bulletproof and can still be penetrated by certain types of bullets, especially at close range.

5. Is Kevlar the only solution for preventing gunshot injuries?

Kevlar is one of the most widely used solutions for preventing gunshot injuries, but it is not the only one. There are other materials and technologies that can also provide protection against bullets, such as ceramic armor and liquid armor. Additionally, there are other strategies for reducing gun violence, such as implementing stricter gun control laws and promoting non-violent conflict resolution.

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