Fluid-filled helmet liner concept for protection against blast-induced traumatic brain injury

Abstract

Due to changes in modem warfare threats, as well as advances in body armor, soldier survivability in combat has increased, but blast-induced Traumatic Brain Injury (TBI) has become a prevalent injury in the battlefield. Often referred to as the "signature wound" of the current U.S. conflicts, blast-induced TBI is not a very well understood injury. In an effort to gain more insight on blast mechanisms and TBI, and to increase protection against this injury, our study investigates the development and exploration of a new Advanced Combat Helmet (ACH) liner for the modem day soldier. The key component of the liner explored in this work is the addition of channels within foam that contain fluid or fluid-like materials. To support this goal, this thesis explores the response of these filler materials in a 2D sandwich structure at a range of pressures believed to be in the range of the occurrence of mild TBI, the most common TBI diagnosis among soldiers. Filler materials explored in this work are glass beads and glycerin. Experiments were performed at Purdue University and the University of Nebraska at Lincoln, using two different shock tube setups to produce incident blast waves. Peak transmitted pressure was used to assess filler materials' blast mitigation abilities, and any nonlinear behavior was explored over the range of incident pressures tested. Results indicate a nonlinear effect in the mitigation of blasts by solid foam and glass beads. These materials respond linearly to applied pressures at 15, 30, and 45 psi, but digress from linear behavior at 60 psi applied pressure. It was also determined that there is a significant advantage to using sandwiches with glass beads compared to solid foam at 60 psi applied pressure, but at 15 psi, 30 psi, and 45 psi, there is no significant difference among all three materials explored.