Doctoral Dissertations
Keywords and Phrases
Blast-induced traumatic brain injury (bTBI); combat helmet; free-field blast; overpressure; Schlieren imagery; Underwash effect
Abstract
"Ballistic resistance of military helmet designs is a prioritized feature to protect warfighters from traumatic brain injury. However, injuries from shock-based threats have not been optimized for warfighter protection and have resulted in the prevalence of blast-induced traumatic brain injury (bTBI). Research gaps were identified in understanding the under wash effect using free field blasts and schlieren imagery. Thus, the following were investigated: (1) overpressure changes on a warfighter’s head due to directionality from a blast, (2) shock wave dampening effects of viscoelastic materials in helmets, and (3) geometric effects of a helmet brim design in the reduction of bTBI. Both methods were employed to assess the effects of blast directionality. The viscoelastic material was evaluated using free-field blasts, and the brim designs were assessed using schlieren imagery to visualize the wave flow. Measurements underwent direct and mathematical comparisons using time-pressure waveforms and the root mean square calculations. Results showed that the helmet trapped the shock waves within the cavity, creating regions of high overpressure and prolonging pressure exposure, but peak pressure and impulse were reduced at a 90-degree orientation. The viscoelastic liner was effective in reducing overpressure under the helmet by decreasing helmet cavity volume. However, alterations in the helmet brim design did not affect shock infiltration into the helmet due to the shock diffracting around the brims regardless of the angle employed. Also, shock energy was transmitted through or traveled around added pads rather than impeding flow into the helmet cavity. This dissertation demonstrates the difficulty in restricting shock wave infiltration into the helmet cavity and identifies potential methods for reducing overpressure on a warfighter to reduce the prevalence of bTBI"-- Abstract, p. iv
Advisor(s)
Johnson, Catherine E.
Committee Member(s)
Dogan, Fatih
Xu, Guang
Williams, Kelly
Perry, Kyle A.
Department(s)
Mining Engineering
Degree Name
Ph. D. in Explosives Engineering
Publisher
Missouri University of Science and Technology
Publication Date
Spring 2025
Pagination
xviii, 156 pages
Note about bibliography
Includes_bibliographical_references_(pages 58, 100, 133 and 150-155)
Rights
©2024 Cody JH Thomas , All Rights Reserved
Document Type
Dissertation - Open Access
File Type
text
Language
English
Thesis Number
T 12475
Recommended Citation
Thomas, Cody JH, "Investigation Of Shockwave Behavior To Inform Helmet Design Using Schlieren Imagery And Free-Field Blasts" (2025). Doctoral Dissertations. 3378.
https://scholarsmine.mst.edu/doctoral_dissertations/3378
