Development of a helmet liner for protection against blast induced trauma
Name
639232389-MIT.pdf
Description
Full printable version
Size
32.98 MB
Format
Adobe PDF
Checksum (MD5)
59fe0d604357788db24f34e24d24d017
Author(s)
Christou, George Alexander
Advisor(s)
Laurence R. Young.
Date Issued
2010
Publisher
Massachusetts Institute of Technology
Abstract
Traumatic brain injuries caused by shock waves have attracted increased medical and scientific attention due to the 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 in the field of shock wave mitigation strategies and the development of a helmet liner for protection against blast induced trauma. The proposed helmet liner design is based on the introduction of solid and fluid filler materials inside channels opened in the interior of a foam liner in order to 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 and particle size of solid filler materials. Specific goals of this research project include the reduction of the peak pressure and pressure gradient of the transmitted wave through the helmet liner and the enhancement of the spatial distribution of the energy of the incoming shock wave.
(cont.)This research effort employed both shock tube experiments and numerical studies in order to investigate the effectiveness of the proposed helmet liner design. Quantitative results have shown that the use of high density filler materials result in higher attenuation levels than low density materials while comparing to solid foam control samples. The peak transmitted overpressure and pressure gradient were significantly reduced with the use of high density materials while the duration of the positive phase was increased. This response resulted in lower overall impulse values of the transmitted wave. The use of high density filler materials also results in superior frequency distribution.
Description
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 211-215).
Subjects
Aeronautics and Astronautics.
MIT Department
Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
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