Composite Helmet Liner to Mitigate Blast Shockwave Energy and Reduce Traumatic Brain Injuries

Abstract

A composite material for mitigating blast shockwave energy, comprising a rubber compound layer impregnated with a shear thickening fluid. The layered composite material comprises a first layer of soft foam, a second layer of hard foam, a third layer of thermoset or thermoplastic compound, and a fourth layer of the rubber compound. The layered composite material does not comprise any fibers or yarns. The layers are bound together and have a total height of less than 0.85 inches. It attenuates up to 80% of an incident blast shockwave impulse and up to 61% of an incident blast shockwave pressure for an incident blast shockwave of 50 psi. A helmet liner made of the layered composite material and capable of fitting a helmet such there are no gaps between the user's head and the helmet during use. The helmet liner may be a flat headband that folds into a helmet's edges.

What is claimed is: 
     
         1 . A layered composite material for mitigating blast shockwave energy, the layered composite material comprising:
 a) a first layer comprising a soft foam;   b) a second layer comprising a hard foam;   c) a third layer comprising a thermoset or thermoplastic compound; and,   d) a fourth layer comprising a rubber compound, wherein the rubber compound does not comprise any fibers or yarns;   wherein, the first layer is bound to the second layer, the second layer is bound to the third layer, and the third layer is bound to the fourth layer;   wherein, the rubber compound is impregnated with a shear thickening fluid, wherein the shear thickening fluid comprises a silica aerogel and an organic glycol;   wherein, the layered composite material has a height less than 0.85 inches; and,   wherein, the layered composite material attenuates at least 62% of an incident blast shockwave impulse for an incident blast shockwave with an incident blast pressure of 50 psi.   
     
     
         2 . The layered composite material as in  claim 1 , wherein the rubber compound comprises 15-25 wt % silica aerogel. 
     
     
         3 . The layered composite material as in  claim 1 , wherein the rubber compound is ethylene propylene diene monomer. 
     
     
         4 . The layered composite material as in  claim 1 , wherein the layered composite material attenuates at least 79% of an incident blast shockwave impulse for an incident blast shockwave with an incident blast pressure of 50 psi. 
     
     
         5 . The layered composite material as in  claim 4 , wherein the layered composite material attenuates at least 79% of an incident blast shockwave impulse and at least 61% of an incident blast shockwave pressure for an incident blast shockwave with an incident blast pressure of 50 psi. 
     
     
         6 . The layered composite material as in  claim 1 , wherein the first layer, the second layer, the third layer, and the fourth layer are arranged such that the fourth layer contacts an incoming shockwave before the third layer, the third layer contacts an incoming shockwave before the second layer, and the second layer contacts an incoming shockwave before the first layer. 
     
     
         7 . The layered composite material as in  claim 1 , wherein the fourth layer has a height of 0.0625-0.125 inches. 
     
     
         8 . A helmet liner for mitigating blast shockwave energy, the helmet liner comprising:
 a) a first layer comprising a soft foam;   b) a second layer comprising a hard foam;   c) a third layer comprising a thermoset or thermoplastic compound; and,   d) a fourth layer comprising a rubber compound, wherein the rubber compound does not comprise any fibers or yarns;   wherein, the first layer is bound to the second layer, the second layer is bound to the third layer, and the third layer is bound to the fourth layer;   wherein, the rubber compound is impregnated with a shear thickening fluid, wherein the shear thickening fluid comprises a silica aerogel and an organic glycol;   wherein, the helmet liner has a height less than 0.85 inches;   wherein, the helmet liner attenuates at least 62% of an incident blast shockwave impulse for an incident blast shockwave with an incident blast pressure of 50 psi; and,   wherein, the helmet liner fits in a helmet such that the first layer contacts a user's head and the fourth layer contacts the helmet such that there are no gaps between the user's head and the helmet during use.   
     
     
         9 . The helmet liner as in  claim 8 , wherein the rubber compound comprises 15-25 wt % silica aerogel. 
     
     
         10 . The helmet liner as in  claim 8 , wherein the rubber compound is ethylene propylene diene monomer. 
     
     
         11 . The helmet liner as in  claim 8 , wherein the helmet liner attenuates at least 79% of an incident blast shockwave impulse for an incident blast shockwave with an incident blast pressure of 50 psi. 
     
     
         12 . The helmet liner as in  claim 8 , wherein the helmet liner attenuates at least 79% of an incident blast shockwave impulse and at least 61% of an incident blast shockwave pressure, wherein the incident blast shockwave has an incident blast pressure of 50 psi. 
     
     
         13 . The helmet liner as in  claim 8 , wherein the fourth layer has a height of 0.0625-0.125 inches. 
     
     
         14 . The helmet liner as in  claim 8 , wherein the helmet liner is a headband, and wherein the headband fits in a helmet's inner edges such that there are no gaps between the user's head and the helmet during use. 
     
     
         15 . The helmet liner as in  claim 14 , wherein the helmet liner further comprises at least one cut in the headband such that the headband lies flat when not in use, and wherein the headband can be folded into the helmet's inner edges such that there are no gaps between the user's head and the helmet during use. 
     
     
         16 . The helmet liner as in  claim 14 , wherein the helmet liner can be reused more than 1 time. 
     
     
         17 . A method for attenuating blast shockwave pressure and impulse, the method comprising the steps:
 a) providing a rubber compound;   b) impregnating the rubber compound with a shear thickening fluid, wherein the shear thickening fluid comprises a silica aerogel and an organic glycol;   c) forming a protective rubber layer with the rubber compound with a height of 0.0625-0.5 inches; and   d) using the protective rubber layer as a barrier for an incoming blast shockwave; and,   wherein, the rubber compound and the protective rubber layer do not comprise any fibers or yarns.   
     
     
         18 . The method as in  claim 17 , further comprising the steps:
 e) providing a soft foam layer;   f) providing a hard foam layer;   g) providing a thermoset or thermoplastic layer;   h) binding the protective rubber layer to the thermoset or thermoplastic layer, the thermoset or thermoplastic layer to the hard foam layer, and the hard foam layer to the soft foam layer and forming a layered composite liner; and,   i) orienting the layered composite liner such that the protective rubber layer receives an incoming blast shockwave before the thermoset or thermoplastic layer, the thermoset or thermoplastic layer receives an incoming blast shockwave before the hard foam layer, and the hard foam layer receives an incoming blast shockwave before the soft foam layer.   
     
     
         19 . The method as in  claim 18 , further comprising the step:
 j) attenuating at least 79% of an incident blast shockwave impulse and at least 61% of an incident blast shockwave pressure for an incident blast shockwave with an incident blast pressure of 50 psi.   
     
     
         20 . The method as in  claim 18 , wherein the rubber compound is ethylene propylene diene monomer.