Isaac, O., Alshammari, O., Clarke, S. et al. (1 more author) (2022) Experimental investigation of blast mitigation of pre-fractal obstacles. International Journal of Protective Structures. ISSN 2041-4196
Abstract
Obstacles arranged into a pre-fractal shape (Sierpinski carpet) were tested for their blast attenuation abilities using 250 g PE4 at three different scaled distances (Z = 1.87, 2.24, 2.99 m/kg1/3). Three pre-fractal iterations were tested, as well as free-field tests for comparative purposes. Reductions in peak overpressure up to 26% and peak specific impulse up to 19% were observed, attributed to a mechanism known as ‘trapping’. This mechanism is characterised by a reduction in the ability of a blast wave to advect downstream, with corresponding increases in pressure observed within the bounds of the pre-fractal obstacle. Attenuation magnitudes and areas of reduced pressure and impulse were found to be drastically different with each pre-fractal iteration, with a transition from shadowing to wave trapping as the obstacles more closely resembled true fractals. A linear dependence on a newly-defined obstruction factor (OF) was found for arrival time, overpressure and impulse at the sensor locations, suggesting that the attenuation of a pre-fractal obstacle is inherently determinable. The results indicate that the mechanism of blast mitigation of pre-fractal obstacles is fundamentally different from singular or arrays of regular obstacles, and could be exploited further to develop novel protective structures with enhanced blast attenuation.
Metadata
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Copyright, Publisher and Additional Information: | © 2022 The Authors. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. | ||||
Keywords: | Blast-obstacle interaction; experimental study; mitigation; pre-fractal; Sierpinski carpet | ||||
Dates: |
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Institution: | The University of Sheffield | ||||
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Civil and Structural Engineering (Sheffield) | ||||
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Depositing User: | Symplectic Sheffield | ||||
Date Deposited: | 16 Dec 2022 15:13 | ||||
Last Modified: | 16 Dec 2022 15:13 | ||||
Status: | Published online | ||||
Publisher: | Multi-Science Publishing | ||||
Refereed: | Yes | ||||
Identification Number: | https://doi.org/10.1177/20414196221144066 |