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Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development / DAVID HOWELLS

Swansea University Author: DAVID HOWELLS

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DOI (Published version): 10.23889/SUThesis.68225

Abstract

Primary blast lung injury is a contributor to lethality in both military and civilian life. Mitigation of such injuries is a topic which would benefit from deeper investigations of the mechanism(s) by which these injuries manifest. For this purpose, this study has developed 1D and 3D finite element...

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Published: Swansea, Wales, UK 2024
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Arora, Hari
URI: https://cronfa.swan.ac.uk/Record/cronfa68225
first_indexed 2024-11-25T14:21:41Z
last_indexed 2025-02-11T05:52:23Z
id cronfa68225
recordtype RisThesis
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spelling 2025-02-10T12:10:14.9100002 v2 68225 2024-11-11 Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development 94d6e95cc4a1f27a9faa53d065d938de DAVID HOWELLS DAVID HOWELLS true false 2024-11-11 Primary blast lung injury is a contributor to lethality in both military and civilian life. Mitigation of such injuries is a topic which would benefit from deeper investigations of the mechanism(s) by which these injuries manifest. For this purpose, this study has developed 1D and 3D finite element models alongside physical models of the human thorax to be used in blast simulations and experimental testing respectively. The initial hypothesis was that injury was governed by the action of stress waves within a few milliseconds after loading begins. The threshold of injury scenario outlined in the literature was investigated with consideration for the differences in loading (long-duration and short-duration). A comparison of the 1D and 3D computational models indicated that 1D modelling was insufficient in capturing the requirements for accurately predicting blast injury. Several parameters were explored computationally as metrics for prediction of primary blast lung injury. The conclusion formed was that tensive stress presents the most consistent indicator of injury in both long-duration and short-duration blasts. A value of 8.7kPa was proposed as a threshold value for injury using this parameter. This is substantially lower than the external loads applied. Distributions of all stresses in the 3D computational models were indicative of realistic injury distribution, proven through comparison of the time varying position of stress contours with CT images of PBLI victims. A reduced-scale physical thorax model was constructed following a material characterisation study of PolyJet materials. Experimental blast loading of this model using a shock tube indicating that the external load was representative of the internal loads. Results were inconclusive due to excessive vibrations, however there are indications that reflections scattered by the mediastinum were detected. This first iteration of the model can undergo significant improvements and represents a promising platform for future investigations of primary blast lung injury. E-Thesis Swansea, Wales, UK Mechanical Engineering, Medical Engineering, Blast, PBLI, FEM 4 6 2024 2024-06-04 10.23889/SUThesis.68225 COLLEGE NANME COLLEGE CODE Swansea University Arora, Hari Doctoral Ph.D KESS II; Radnor Range KESS II; Radnor Range 2025-02-10T12:10:14.9100002 2024-11-11T12:08:59.7768149 Faculty of Science and Engineering School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering DAVID HOWELLS 1 68225__32906__b47fe42dc3fd4d5fada2738ed9bc96cc.pdf Howells_David_A_PhD_Thesis_Final_Cronfa.pdf 2024-11-11T12:48:59.6354902 Output 6874850 application/pdf E-Thesis – open access true Copyright: The Author, David A. Howells, 2024. true eng
title Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
spellingShingle Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
DAVID HOWELLS
title_short Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
title_full Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
title_fullStr Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
title_full_unstemmed Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
title_sort Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development
author_id_str_mv 94d6e95cc4a1f27a9faa53d065d938de
author_id_fullname_str_mv 94d6e95cc4a1f27a9faa53d065d938de_***_DAVID HOWELLS
author DAVID HOWELLS
author2 DAVID HOWELLS
format E-Thesis
publishDate 2024
institution Swansea University
doi_str_mv 10.23889/SUThesis.68225
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Aerospace, Civil, Electrical, General and Mechanical Engineering - Mechanical Engineering
document_store_str 1
active_str 0
description Primary blast lung injury is a contributor to lethality in both military and civilian life. Mitigation of such injuries is a topic which would benefit from deeper investigations of the mechanism(s) by which these injuries manifest. For this purpose, this study has developed 1D and 3D finite element models alongside physical models of the human thorax to be used in blast simulations and experimental testing respectively. The initial hypothesis was that injury was governed by the action of stress waves within a few milliseconds after loading begins. The threshold of injury scenario outlined in the literature was investigated with consideration for the differences in loading (long-duration and short-duration). A comparison of the 1D and 3D computational models indicated that 1D modelling was insufficient in capturing the requirements for accurately predicting blast injury. Several parameters were explored computationally as metrics for prediction of primary blast lung injury. The conclusion formed was that tensive stress presents the most consistent indicator of injury in both long-duration and short-duration blasts. A value of 8.7kPa was proposed as a threshold value for injury using this parameter. This is substantially lower than the external loads applied. Distributions of all stresses in the 3D computational models were indicative of realistic injury distribution, proven through comparison of the time varying position of stress contours with CT images of PBLI victims. A reduced-scale physical thorax model was constructed following a material characterisation study of PolyJet materials. Experimental blast loading of this model using a shock tube indicating that the external load was representative of the internal loads. Results were inconclusive due to excessive vibrations, however there are indications that reflections scattered by the mediastinum were detected. This first iteration of the model can undergo significant improvements and represents a promising platform for future investigations of primary blast lung injury.
published_date 2024-06-04T17:44:00Z
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score 11.08899

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