Handout 1 - Clemson University

Development of a Helmet Liner for Protection Against Blast
Abstract
Induced Trauma
by
George Alexander Christou
Submitted to the Department of Aeronautics and Astronautics
on January 29, 2010, in partial fulfillment of the
requirements for the Degree of Master of Science in
Aeronautics and Astronautics
Traumatic brain injuries caused by shock waves attracted have increased medical and
scientific attention to the due large percentage of combat troops that have sustained
such injuries in recent conflict theatres. To this day, the knowledge in the fields of
causes, effects and identification of traumatic brain injury is limited. The use of
advanced body armor has decreased the number of fatalities from fragments observed
in previous military operations, resulting in the increase of non-fatal brain injuries from
shock waves.
The purpose of this project is the advancement of the knowledge the field in of
shock wave mitigation strategies and the development of helmet a liner for protection
against blast trauma. induced The proposed helmet liner design is based on the
introduction of solid and fluid filler materials channels inside opened in the interior of a
foam liner order to in enhance the attenuation of incoming shock waves. Primary
investigated attenuation mechanisms include acoustic impedance mismatches between
the filler and foam material interfaces, viscous effects of fluid fillers, porosity
particle size of solid filler materials. Specific goals of this research project include the
and
reduction of the peak pressure and pressure gradient of the transmitted wave through
the helmet liner and the enhancement of the
incoming shock wave.
spatial distribution of the energy of the
This research effort employed both shock tube experiments and numerical
in order to investigate the effectiveness of the proposed helmet liner design.
studies
Quantitative have results shown that the use of high density filler materials result in
higher attenuation levels than low density materials comparing while to solid foam