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CMF bulletproof body armor

  1. Apr 9, 2016 #1

    jim mcnamara

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    Staff: Mentor

    http://phys.org/news/2016-04-metal-foam-obliterates-bullets.html
    The CMF armor on collision literally converts the projectile into small particles, spraying out.
    This is interesting and definitely not my area.

    Watch the attached video.
    Questions:
    1. the particles resulting from the hit have to have kinetic energy, if some particles are redirected to unprotected area (example: projectile hits high, just above the top of the sternum, redirect up into the lower jaw), are they a problem?

    2. Impulse from the collision should push the armor back into the wearer of the armor.
    Correct? There should be some negative consequences to the wearer at the point of impact.

    Assumption:
    There is no free lunch, if you ameliorate one issue, in this case severe or fatal wounds, then there there has to be some trade off. Please correct me.
     
  2. jcsd
  3. Apr 9, 2016 #2
    #1. As a body armor suit, tests would have to be conducted. Best secondary means of protection might be of such as a type of flexible ski mask covering over the head, neck, upper chest of perhaps similar or same material but of lessor depth, to accept debris from a hit. I presume there is no way to ever certify a 100% full protection.
    #2. Sure, an impact would hurt and bruise. I don't see any way around that , if there is to be mobility for the user. Maybe they could design an armor suit like the more rigid kind for a knight, so as to reduce localized trauma ( correct medical term escapes me right now ) - though that model might not be so user friendly.

    Just throwing out some thoughts on the subject.
     
  4. Apr 9, 2016 #3
  5. Mar 7, 2017 #4
    If you are using the most common hard armor that the military uses it is made of a ceramic plate that acts as a sacrificial layer. The plate breaks and the round stays mostly intact but it looses all of it's energy. Most metal plate armors have the same issue of bullets spalling upon impact. These fragments can cause injury and harm to the individual wearing the armor. Having a secondary armor patch attached to the face would be very uncomfortable for the wearer and would add another layer of cost to either the person, company, or government. Armor production companies like www.ar500armor.com usually add an anti-spalling coating to the strike face of the armor. This is usually a plastic coating similar in composition to Line-X http://www.linex.com/protective-coatings/security-and-defense this captures the bullet fragments so that you don't experience any secondary injuries.
    As far as the impact felt when the bullet hits there are a few things that help out. Most military style body armors use a back layer of Kevlar like material, this is usually rated for Level III-A which would stop handgun rounds by itself. Soft armor stops rounds by dissipating the energy and since most handgun rounds are not pointed like rifle rounds you just need to slow them down enough to not penetrate your skin. This layer also acts as a shock absorber for the more high energy rounds that you need hard armor to stop. Some individuals also elect to add a third layer behind the soft armor and that would be what is known as a trauma pad. This is a pad that is made of layers of non-newtonian fluid and padding. It further mitigates the shock of bullet impact on the wearer, more info here http://www.ar500armor.com/ar500-armor-trauma-pad-10-x-12-asc.html
    I personally would cannibalize multiple different types of armor for my personal use (if I had the money to do this). I would use a combo of the following:
    1-CMF plates with Line-X anti-spalling coating, front+back+2 sides
    2-Carbon nanotube soft armor https://ctznarmor.com/product/shtf-tactical-xpc/
    3-Trauma pad
    4-Plate carrier with slots for all 4 plates http://www.blackhawk.com/Products/P...rriers/S-T-R-I-K-E-Cutaway-Plate-Carrier.aspx

    I hope this helps answer some of your questions.
     
  6. Mar 20, 2017 #5
    Here is a video of some cheaper armor stopping the same bullet fired (Tungsten-Core M2AP) from the same cartridge (30-06). You can see behind the plate that there are significant impact forces from the bullet. However, it stopped the bullet.


    Also, those metal fragments that you see coming from the bullet are not coming from the armor-penetrating component. The armor-penetrating component is actually a tungsten steel core that is contained inside of the bullet. What you see in the video is merely copper jacketing that will spall like that on any hard body armor. I'd like to see the condition of the tungsten steel core itself. I find that they rarely deform and I doubt that this one did either. I don't doubt that it stopped, but it probably did not deform.

    H
     
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