{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/58280"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/58280","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Development of a helmet liner for protection against blast induced trauma","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.","abstract_html":"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.","abstract_has_math":false,"creators":["Christou, George Alexander"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.","school":null,"contributors":[],"advisors":["Laurence R. Young."],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010","date_published":"2010","updated_at":"2026-07-22T22:22:16Z","subjects":["Aeronautics and Astronautics."],"languages":["eng"],"rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/58280","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Laurence R. 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They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/58280"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["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)."]},{"key":"dc:description.abstract","label":"Abstract","values":["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."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.M."]},{"key":"dc:title","label":"Title","values":["Development of a helmet liner for protection against blast induced trauma"]}]}],"canonical_facts":{"dc:contributor.advisor":["Laurence R. Young."],"dc:contributor.department":["Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics."],"dc:contributor.other":["Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics."],"dc:creator":["Christou, George Alexander"],"dc:date.accessioned":["2010-09-02T17:21:02Z"],"dc:date.available":["2010-09-02T17:21:02Z"],"dc:date.issued":["2010"],"dc: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)."],"dc:description.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."],"dc:description.degree":["S.M."],"dc:identifier.uri":["http://hdl.handle.net/1721.1/58280"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Aeronautics and Astronautics."],"dc:title":["Development of a helmet liner for protection against blast induced trauma"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:22:16Z"}