The purpose of Kevlar is not just to stop the bullet but also to dissipate the bullet’s energy so that it doesn’t cause as much damage. In order to test Kevlar’s ability to dissipate energy, I had to shoot at gel with Kevlar in front of it and compare against gel without Kevlar. I can take the difference in energy to see how much the Kevlar helps, and even compare different numbers of layers.
The equipment is the same as in the previous
test only with the addition of the sheets of Kevlar 29 style 735.
Figure 11. Kevlar layers placed between box and shield.
The procedure is almost exactly the same as before the only difference being the addition of Kevlar. The tests will include increasing increments of four layers of Kevlar (4, 8, 12, etc) in front of the gel.
Figure 12. Eight (8) layers of Kevlar clipped together.
The percentage of energy dissipated (KEd) will found by the equation
KEd = {[(KEk – KEg) / KEk] * 100%}
Where
KEk = ½ mvk2 = minimum energy to break egg in gel with Kevlar
KEg = ½ mvg2 = minimum energy to break egg in gel without Kevlar (See Table 4.)
Results
Table 6. Energy dissipation of 4 layers of Kevlar.
Table 7. Energy dissipation of 8 layers of Kevlar.
Table 8. Energy dissipation of 12 layers of Kevlar.
These tests show that Kevlar not only helps to
stop a projectile, but also does a very good job of dissipating the energy to
keep it from damaging internal organs. The test with four layers of Kevlar
dissipated 54.78% of the energy on impact, the eight layers dissipated 75.84%,
and the twelve layers dissipated 81.68%. This means that when struck by a
projectile like a bullet, most of the energy is spread out protecting vital
organs that could be damaged by the shockwave.
Next : Determining Blunt Trauma