Elastic Jamming – A new concept to make penetration resistant yet flexible composites

R. Selvaganapathy, D. Farouzi
McMaster University, Hamilton, Canada

Keywords: Puncture Resistance, Ballistics, Flexible Body Armor

We have developed a new concept called elastic jamming wherein high density of hard nanoparticles packed in a elastomeric matrix can jam when impinged with a sudden compressive force such as from a needle or a bullet and cause dissipation of that force over a wider area. The solid state nature of this composite makes is ideal for integration with gloves, clothing and fabrics to make them penetration resistant. The elastic matrix makes the material flexible to tensile forces. We have developed new composite designs is developed to improve penetration resistance of textiles against hypodermic needle, spike penetrator, and ballistic threats using a high concentration of nano-sized and micron-sized hard particles in elastomeric mixtures. Normalized penetration resistance of high-density polyethylene (HDPE) fabric against 21G hypodermic needle increased up to 190%. Additionally, this material can be integrated with cotton fabrics to increase their resistance from 1-2 N to >10 N against 25G hypodermic needle. Recently, we are investigating multilayer laminated composites of this material for ballistic protection. Preliminary results show that the laminates can stop 9 mm ammunition with minimal backface signature while still maintaining their flexibility. This work provides new insight for the design of flexible body protection.