E-Thesis 52 views
Protection Optimisation via Novel Simulation (PONS) – A Bridge to the Next Generation of Armour Development / DAVID HOWELLS
Swansea University Author: DAVID HOWELLS
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...
| Published: |
Swansea, Wales, UK
2024
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | Ph.D |
| Supervisor: | Arora, Hari |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa68225 |
| 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 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. |
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| Keywords: |
Mechanical Engineering, Medical Engineering, Blast, PBLI, FEM |
| College: |
Faculty of Science and Engineering |
| Funders: |
KESS II; Radnor Range |