body armor and blunt force trauma

Discussion in 'Off-topic' started by gunsmoker, Jan 4, 2011.

  1. gunsmoker

    gunsmoker Lawyer and Gun Activist

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    In the movies, people who get shot while wearing soft body armor fall down, but then get up after a brief period and they're good as new.

    In the news reports, officers who get shot while wearing body armor are usually treated for injuries, but not life threatening ones.

    Here's an article where a 16 year old kid was the catcher in a baseball game. A baseball hit him in the chest, but his chest was protected by a pad.
    The boy died.
    http://www.cnn.com/2010/US/12/08/new.jersey.baseball.death/index.html?iref=obinsiteFrom what I can find online, a baseball thrown at 95 mph will generate about 90 foot-pounds of energy. This puts it on the same level with a .22LR or maybe some mild .32 acp and .32 revolver rounds.

    The point is that even though most of the time blunt force trauma is not fatal when you're hit with a light weight object moving fast, it sometimes can be. Keep that in mind when wearing body armor. Keep that in mind also if somebody is about to punch you or strike you with something or throw a rock at you.
     
  2. mygunstoo

    mygunstoo Active Member

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    Eventhough there is no penetration of the projectile into the flesh, the shock wave "cone" at impact can cause tissue damage. At chest level, the baseball impact can send fragments of bones to the heart/lungs.
     

  3. SongDogSniper

    SongDogSniper New Member

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    OTOH.....

    Vest Saves Ohio Police Officer Shot in Chest

    ASHTABULA, Ohio -- Police in Millcreek Township, Pa., captured the 20-year-old man Monday night suspected of shooting Ashtabula Police Lt. Rodney Blaney at about 11 a.m. that day.

    Blaney, a five-year veteran of the police force, was shot once in the chest after stopping two men in a suspicious vehicle in the 900 block of West 38th Street, between Ann and West avenues. As Blaney exited his vehicle, Miguel A. Alsina Jr. came out of the car and started firing a handgun at Blaney, Ashtabula police Lt. John Koski said.

    "(Blaney) took a hit, but he was wearing his (bulletproof) vest," Koski said. "He was able to return fire."

    Full story here....
     
  4. cliffhanger

    cliffhanger Active Member

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    It doesn't have to cause physical damage (bone fragments). It just has to hit at the right (wrong) time in the heart beat. http://en.wikipedia.org/wiki/Commotio_cordis. It appears to kill 2 or 3 kids each year in Little League Baseball...

    Cliffhanger
     
  5. MrMorden

    MrMorden New Member

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    The "chest hit death" thing is typically *not* caused by tissue damage, but is rather a reaction of the heart to the impact at a specific point in its rhythm. From wikipedia:

    Commotio cordis (Latin, "agitation of the heart") is a disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart (the precordial region), at a critical time during the cycle of a heart beat. It is a form of ventricular fibrillation, not mechanical damage to the heart muscle or surrounding organs, and not the result of heart disease. The fatality rate is about 65%. It can sometimes, but not always, be reversed by defibrillation.
     
  6. vooduchikn

    vooduchikn New Member

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    Body armor is good stuff. It keeps (hopefully) the bullet from penetrating flesh which ultimately causes bleeding (loss of blood pressure), heart failure and ultimately death.

    The vest will not stop F=MA. You will get hurt, experience pain, broken bones, collapsed lungs, and maybe even death depending on where the impact is. The fatdaddy ceramic plate still has to transfer the energy it takes from a round somewhere. Guess what, its you if you are wearing it. Lets not forget that a knife stabs through Kevlar like a toothpick through some well smoked ribs.

    A baseball, soccer ball, or a beer bottle all adhere to this simple logic.

    Gunsmoker has brought up a very good topic. Are our youth really tossing fastballs hard enough to kill or is the protection we are giving are kids enough?

    Either way, makes you think as a parent when your kid is in little league.
     
  7. kestak

    kestak New Member

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    95 miles per hour is about 140 feet per seconds.

    A baseball weight around 5.25 ounces. It is 2300 grains.

    The ft.lbs energy is 164.

    22LR has about 117 ft.lbs
    45ACP has about 400 ft.lbs.
    44 magnum has about 1000 ft.lbs :mrgreen:
     
  8. vooduchikn

    vooduchikn New Member

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    Thanks for doing the math kestak. I was only trying to make a simple point.

    Body armor will not save you if the impact is in the right place. Know a guy that died from internal bleeding after suffering a GS at ~30 yards with several 7.62x54 rounds just below his ribcage, impact ruptured his spleen, split his liver and the doc pulled his last pieces of his previous meal out out of his windpipe trying to save him. Impact broke most of his ribs on his right side along with his sternum. Stopped his heart as well. Doc got his motor back up and running, but he expired due to internal bleeding before he could get the attention he needed on the flight back to homeplate.

    2 rounds were later recovered from his vest. Neither penetrated his body, both were opened up.
     
  9. kestak

    kestak New Member

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    Greetings,

    A long time ago, when I was doing Yoseikan Karate-do, after we prove our worthiness and we were in a highly advanced "grade" (post-Black belt), we got thought lethal hits. Of course, we already knew some of them because our senseis told us where to avoid to hit while doing competition or combat.

    Anyway.... After that training, it made me realize how the human body is fragile and how many weak points we have:
    - hit to sternum
    - third left rib breaks very easily
    - front throat little bone (adam's apple??? in english)
    - all the back of the neck but especially the big bumb at the base of the skull
    - hit to carothide arteries
    - Hit to the nose up (not like in the movies with the side of the hand of course, tou have 90% chances to miss the hit and I won't tell you how... :cantsay: )
    etc....
     
  10. EJR914

    EJR914 Cheezburger Operator

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    Ceramic Plates.....
     
  11. NTA

    NTA Well-Known Member

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    In movies:
    "Don't worry, its just a flesh wound !"
     
  12. kestak

    kestak New Member

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    Greetings,

    I am kind of disappointed that no one brought the surface of impact... Don't we have a few physicians here????

    We tend to look at only the total energy transferred from the projectile to the body. There is another variable that is the surface of the area hit that will cause a different kind of damage.

    You can do a little exercise at home. Take a pen and fill up a bucket of water. One end is flat, the other one is sharp. Let fall the pen into the water from the same eight and notice how the shock wave is different for each ends. The flat end produces bigger waves.

    "Bigger waves" will produce more trauma damage on the body (Excluding the penetration) because there is a bigger displacement. You are not talking more energy. It is the same weight and same speed, hence same energy. Some people who want to look smart, were writing about hydrostatic shock... :sly: There is no such thing in the human body. We have too much solid matter. It is more a matter wave shock we are experiencing literally destroying the bio cells cohesion in two ways: the cells walls and the cells cohesion glued together.

    There is no doubt trauma pads save lives because they stop the penetration and they prevent the waves on the body (what soft armour does not, in fact, they make the small bullet acts like a baseball). I think the next step in soft armours will really be to eliminate the big waves effect by changing the frequency and make them small waves or absorbing the energy and creating the waves into the soft armour tissue itself. Maybe it will be changing the "chain"-like tissue to "scales"-like tissue. Studies showed that the knights wearing scales armours withstood better blunt trauma than those wearing rings armours.

    Thank you
    P.S.: I know that the dragon skin armour was a flop. I am not talking about the same thing here.
     
  13. gunsmoker

    gunsmoker Lawyer and Gun Activist

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    I shot my 29.5 year old Point Blank level IIA vest E23C7633-B7BA-4569-AAF2-E6F397828C9E.jpeg 532BA9EA-A963-404F-BE55-A09BDA73AF0A.jpeg last weekend.

    It stopped all the slugs I threw at it. 9mm FMJ fired from Glock 19. .45 ACP 200-gr. JHP from a Colt Commander. And a .357 magnum 140-gr. lead round nose that was fired from so close it left powder burns the vest.


    But the backface deformation (akso called "backface signature) was significant. That 9 mm caused a three-quarter inch dent in the huge block of red Georgia clay which I had set the vest panel against for that shot .

    I decided to use something softer, more flexible, and energy absorbing for the next two test shots. I chose two boxes of cereal, brand new full sealed in the package.

    The 45 tore a huge hole in one side of the first cereal box even though it did not penetrate the vest . The impact shockwave went through the vest and into the cereal box, pulverizing it.

    Ditto for the 357 magnum, which did even more damage and turned about 1/4 of the cereal into a fine powder .
     
  14. Craftsman

    Craftsman Well-Known Member

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    Modern body armor exists to stop point penetration of high velocity projectiles AND to spread the impact load across time and distance. The wider the impact surface, the less damage, same for spreading the impact energy across more time. The concept of distributing energy across a longer time base is much the same for automobile racing safety equipment. Survivable doesn't mean unhurt. To extend what I said in the other thread, degradation may not mean catastrophic failure, but it could erode the safety margin where there is statistical likelihood of "failure". Failure in this context means sustaining a lethal or life-altering injury from an attack that was originally within the equipment's rated capacity.
     
  15. gunsmoker

    gunsmoker Lawyer and Gun Activist

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    yes, and I don't have any way of measuring backface signature or backface deformation the way the National Institute of Justice has promulgated their testing standards for body armor manufacturers.

    The manufactures of these kinds of vests have to build a big square box filled with modeling clay (non-hardening modeling clay) probably about 100 pounds of it; I think the box is 1 m² and a minimum of 4 inches thick. Very expensive to buy that much clay!

    A vest will fail the test for a certain caliber if a hit to the test panel placed up against the clay box causes a dent in the clay that is 2 inches or more deep.

    I do not think that my vest would fail that test based on the dents and cracks that were made in the newspaper from 1999 and based on the damage to the natural Georgia clay and the cereal boxes in 2018. But that's just a guess .

    I am guessing the 357 magnum would have caused a dent in the clay backer material to a depth of about 1.5 inches (the length of a .38 special live round).

    I have shot this kind of non-hardening modeling clay before with air guns and 22 rimfire bullets. But I've only used at the most 2 pounds of it at a time. But I do know the stuff is pretty dense and the more that you have in a solid block the harder it is to push that material out of the way to make a cavity.