Combat Helmet Liner

TDA Research Inc. will develop a brand-new design for a lightweight liner to be worn underneath a regular combat helmet, complementing the latter, offering enhanced protection against blast and concussive forces.  We will use a new multilayered design, where each layer carries out its own set of functions.  The outer layer of the helmet liner will be made of EPDM rubber and will absorb the majority of the shockwave energy. Moreover, the EPDM rubber layer will be reinforced with Shear Thickening Fluids (also known as liquid armor). Shear Thickening Fluids (STFs) are dense colloidal suspensions that exhibit abrupt increases in viscosity with increasing shear rate, which is reversible when the load is removed. This feature makes STFs the materials of choice for protective gear/armor reinforcements. Even the application of a very thin coating (~1 mil) of STF on a piece of fabric makes it very hard to cut or stab through. However, our goal is for the STF to provide an additional energy absorption mechanism through the motion of the nanoparticles. The STF and EPDM rubber will act synergistically to dissipate and absorb the shockwave energy. The rear layer will be made of a soft polyurethane foam, which will complete the dissipation and absorption of the shockwave energy, providing a complete protection against trauma to the brain. An optional intermediate polyethylene plastic layer will be a potential constraint layer between the two soft layers protecting them from excessive vibrational deformations and absorbing/dissipating additional energy. All the layers will be bonded together into a single structure with a common commercial adhesive.