Comments on: SAFER barriers? http://www.nrfoam.org/closed-cell-foam/safer-barriers/ Wed, 17 Mar 2010 10:13:59 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Mack Man http://www.nrfoam.org/closed-cell-foam/safer-barriers/#comment-943 Mack Man Mon, 09 Nov 2009 23:10:59 +0000 http://www.nrfoam.org/closed-cell-foam/safer-barriers#comment-943 The key element in your question is the dissipation of energy. The SAFER barrier takes the kinetic energy of the of the race car and spreads it over a larger area of the wall as you've stated. The wall is a rigid body, while the barrier a moving one. For the body armor to work it would have to spread the energy over a large area of the body. Kevlar works at least partly due to this reason. However, the body is not a rigid body and likely still subject to some damage. Conceptually a SAFER body armor would somehow need to transfer the blow from a baseball bat to a larger area. This would decrease the localized impact, but could result in a wider injury. I think most people would take a larger bruise over broken bones or internal bleeding though! As a final though, even in the Middle Ages, knights understood the need to prevent penetration of sharp objects into the skin. If you were to take a suit of armor that is stiff enough to withstand the impact, it would still hurt, but be much less of an injury than without. Also, consider the equipment that the catcher and umpires use. The chest protector is flexible, but stiff enough and padded enough that it absorbs some of the impact and distributes the rest over a wider area. Actually that would be a SAFER barrier!<br><b>References : </b><br> The key element in your question is the dissipation of energy. The SAFER barrier takes the kinetic energy of the of the race car and spreads it over a larger area of the wall as you’ve stated. The wall is a rigid body, while the barrier a moving one.

For the body armor to work it would have to spread the energy over a large area of the body. Kevlar works at least partly due to this reason. However, the body is not a rigid body and likely still subject to some damage. Conceptually a SAFER body armor would somehow need to transfer the blow from a baseball bat to a larger area. This would decrease the localized impact, but could result in a wider injury. I think most people would take a larger bruise over broken bones or internal bleeding though!

As a final though, even in the Middle Ages, knights understood the need to prevent penetration of sharp objects into the skin. If you were to take a suit of armor that is stiff enough to withstand the impact, it would still hurt, but be much less of an injury than without.

Also, consider the equipment that the catcher and umpires use. The chest protector is flexible, but stiff enough and padded enough that it absorbs some of the impact and distributes the rest over a wider area. Actually that would be a SAFER barrier!
References :

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