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A new class of Shear Thickening Fluids (STF) is incorporated aramid fibers. The STF is a combination of nanosilica and calcium carbonate nanocrystals, combined with polyethylene glycol. The STF assimilation process into aramid fibers has been accomplished through a combination of ultrasonic dispersion and airbrush, especially developed for this study. Two types of ammunition were considered, i.e. 9mm Full Metal Jacket (FMJ) and .357 Magnum Jacketed Soft Point (JSP). The results demonstrated an enhancement close to 25% in ballistic penetration resistance, due combined performance of aramid fabrics impregnated with STF and the epoxy system. Furthermore, considering only the addition of STF to the aramid fabrics through the improved dispersion technique, an increase on performance close to 41% in ballistic performance was achieved. A normalized equation was proposed, which allows a comparative study between the effect of using non Newtonian fluids and the chest cavity trauma made by high speed projectiles. |
