Far-field positive phase blast parameter characterisation of RDX and PETN based explosives

Abstract

A significant amount of scientific effort has been dedicated to measuring and understanding the effects of explosions, leading to the development of semi-empirical methods for rapid prediction of blast load parameters. The most well-known of these, termed the Kingery and Bulmash method, makes use of polylogarithmic curves derived from a compilation of medium to large scale experimental tests performed over many decades. However, there is still no general consensus on the accuracy and validity of this approach, despite some researchers reporting consistently high levels of agreement. Further, it is still not known whether blast loading can be considered deterministic, or whether it is intrinsically variable, the extent of this variability, and the range and scales over which these variations are observed. This article critically reviews historic and contemporary blast experiments, including newly generated arena tests with RDX and PETN-based explosives, with a view to demonstrating the accuracy with which blast load parameters can be predicted using semi-empirical approaches.

Experimental studies of confined detonations of plasticized high explosives in inert and reactive atmospheres

“…Farrimond et al . [17] present a detailed argument that, given careful control over the test conditions, the expected variability in recorded unconfined blast wave parameters should typically be no more than a few per cent of the mean in far-field scaled regimes ( true0 > 3 m/kg true0 1 / 3 ). A key aim of this study was to assess whether this level of consistency could be observed in the far more complex case of a confined detonation.…”

“…The previous work published by Farrimond et al . [17] characterized PE4, PE8 and PE10 in far-field area-style trials, within which very similar explosive yields were recorded. Presented in this article is an investigation into whether the same explosive compositions behave in a similar manner within a confined scenario.…”

“…The complexity of confined explosions is mainly due to three distinct mechanisms [14,15]. The first mechanism is directly related to the initial propagation of a high-pressure shock wave, which has been reported on in many published articles and defined with high consistency [16,17]. When within a confined space, these interact with boundaries and reflect back towards the explosive centre resulting in complex turbulent interactions within the detonation cloud and further combustion energy release [18]—the second mechanism.…”

Temporally and Spatially Resolved Reflected Overpressure Measurements in the Extreme Near Field

“…To demonstrate the improved performance of the new MaCE pressure bars, this section provides a comparison between CoBL and MaCE facility pressure measurements in the extreme near field. These tests were performed at m/kg , near the limit of the existing CoBL pressure bars, using the plastic explosive PE10 (86% PETN, 14% plasticiser; TNT [ 30 ]). Separate tests were performed in CoBL and MaCE using the same charge arrangement: a 113 g sphere of PE10 was positioned at a stand-off distance of 95 mm (charge centre to target plate surface) by suspending it between two vertical supports in a strip of lightweight glass fibre netting.…”

A Review of Blast Loading in the Urban Environment

“…Scaled distance, Z, can be calculated via Equation (1). These scaling laws allow direct comparisons between explosive events at any reasonable scale, provided the differences in the explosive compounds are accounted for (e.g., shape effects [17][18][19][20], secondary combustion [21], heat of detonation and/or reaction rates [22][23][24][25], etc.). However, some have previously suggested a practical limit to the minimum reasonable scale for gathering experimental data [26].…”