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Airbag questions

  1. Jan 19, 2006 #1
    I was wondering if a modified airbag could serve as a lessener to an explosion?

    If you were trying to protect a safe from an explosion, could an airbag correctly "shaped" divert the initial blast and pressure waves enough to make any difference? would the location of the blast play a decisive role?

    I realize that the inflation system is itself built using explosive components, so I'm not sure if this idea would make the situation better or worse...

    Any thoughts??
  2. jcsd
  3. Jan 19, 2006 #2


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    If you have some matter flying at you at some enormous velocity (let's say gas and shrapnel), it carries momentum.

    If you can manage to accelerate an equal weight of matter to an equivalent velocity, in the opposite direction so that it collides with the incoming matter, the momenta of both would cancel and you would "divert" the incoming explosion.

    If you can detect the approaching explosive debris or shock front ahead of time, and then gently accelerate your counter-mass to an equivalent velocity, you can safely prevent damage.

    Instead of being hit with shrapnel and suffering a very large force over a very small time, you're using another controlled explosion to accelerate counter-mass with a milder force spread over a longer time. This milder force may be "survivable."

    - Warren
  4. Jan 19, 2006 #3
    Yeah, that's basically what I was thinking. One of my concerns was that if the airbag failed to deploy, the inflationary fuel would only make matters much worse. But I am not sure that the airbag inflator is big enough to make much of a difference. Thanks!
  5. Jan 19, 2006 #4


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    Some tanks use active armor - a bomb that explodes outward meets with a shell that is inbound, taking away its momentum. Same idea.
  6. Jan 20, 2006 #5


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    Like Russ mentioned, the "active armor" is used on many of the best tanks.


    and the next page at the bottom of that page:


    It seems the explosive is of most benefit to disrupt shaped charges (like a bazooka or panzer-faust) where the warhead is shaped to focus the hot gases into a stream that melts right through inches of steel armor.

    With kinetic energy shrapnel though, not much can really be done aside from sheer thickness. In space, a flec of paint traveling at 25,000MPH is going to penetrate about anything man-made with ease. A loose bolt that fell off an old space craft is even more scary. So a self-sealing spacecraft that can stop the airleak after the projectile makes it through is a secondary defense to a primary projectile that is best avoided.
  7. Jan 21, 2006 #6
    Awesome - except for the space thing, that seems a little troubling :eek: . The reactive armor designs really seem like they're designed to provide a higher survivability rate, but unfortunately it doesn't seem likely to allow for much mobility after the explosion (in the case of a mine) to allow the soldiers to get the heck out once they've been hit initially. Thanks for the insights.
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