Farrimond, D., Woolford, S., Tyas, A. et al. (6 more authors) (2023) Far-field positive phase blast parameter characterisation of small-scale ammonium nitrate based explosives. In: Proceedings of the 6th International Conference on Protective Structures (ICPS6). 6th International Conference on Protective Structures (ICPS6), 14-17 May 2023, Auburn, AL, United States. International Association of Protective Structures
Abstract
The behaviour of “ideal” explosives, where the energy release is almost entirely facilitated by the process of detonation, is relatively well known. The mechanism of energy release is relatively simple, and consequently it is usually relatively easy to characterise and predict the properties of blast waves resulting from such explosives. With non-ideal explosives, the situation is more complex. Here, at best only part of the energy release is facilitated by a detonation process, and some or all is released via a secondary, usually slower, reaction. This, in addition to the fact that the rates of reactions are often highly sensitive to the thermodynamic state of the partially and fully-reacted products makes characterisation and prediction of blast waves resulting from non-ideal explosives significantly more challenging.
Ammonium nitrate/fuel oil (ANFO) is such a non-ideal explosive. When initiated, the ammonium nitrate detonates, with the resulting products including a small amount of excess oxygen which is able to react with the fuel oil component. A relatively large amount of data exists from tests involving the detonation of large (>>100kg) ANFO charges. In such tests, the velocity of detonation (VoD) tends towards a limit of around 4.5km/s, and the resulting blast waves can be approximated as being equivalent to those from a TNT charge of 0.8-0.85 times the mass of the ANFO charge. However, significantly less information exists on the mechanisms of energy release and the resulting blast waves from detonations of much smaller ANFO charges.
This paper presents blast experimental work through detonation of small scale ANFO (Ammonium Nitrate 94.5% and Fuel Oil 5.5% mixtures) hemispherical charges to assess the validity of current assumptions made about the non-ideal explosive which are currently integrated within best practice modelling methods. Comparisons will be made to detonation of ideal plastic explosives conducting the same methodology and analyse to validate the present ANFO data.
Metadata
Item Type: | Proceedings Paper |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Author(s). For reuse permissions, please contact the Author(s). |
Keywords: | Blast Parameter Variability; Far-field; Positive Phase; Non-ideal; ANFO |
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) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL EP/R045240/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 17 May 2023 13:49 |
Last Modified: | 22 May 2023 13:17 |
Status: | Published |
Publisher: | International Association of Protective Structures |
Refereed: | Yes |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:199176 |