18 Feb 2025

Representation of Live-Fire Energetic Residues from Insensitive Mortar Munitions Using Command-Detonation Testing

Abstract: Command detonation is critical for testing munitions early in the acquisition process, however its representation of energetic residues produced during live fire has not been assessed. Energetic residue deposition rates were measured on snow from live fire of 60 mm and 81 mm IMX-104 mortar munitions and then compared results with previous command-detonation tests of the same munitions. Mean live-fire deposition rates of IMX-104 compounds were: 3800 mg NTO, 34 mg DNAN, 12 mg RDX, and 1.9 mg HMX per 60 mm cartridge (n = 9); and 8000 mg NTO, 60 mg DNAN, 20 mg RDX, and 2 mg HMX per 81 mm cartridge (n = 13). The predominant residue compound NTO was accurately estimated by command detonation for the 60 mm munition but was significantly underestimated for the 81 mm munition. The minor residues of DNAN and RDX were relatively well estimated by command detonation for the 81 mm munition (p = 0.07 and p= 0.014, respectively), but both were significantly underestimated (p < 0.0001) for the 60 mm munition. Despite some of these differences, the ability demonstrated here for command detonation to predict live-fire residue deposition rates to the correct order-of-magnitude supports its utility in assessing environmental impact.

30 Aug 2024

Particle Size Characteristics of Energetic Materials Distributed from Low-Order Functioning Mortar Munitions

Abstract: Particles of explosive filler distributed from low-order (LO) munition functioning are susceptible to dissolution and potential mobilization into groundwater and surface water. We command-initiated three mortar munitions as LO in triplicate using a fuze simulator and recovered particles from an ice surface to constrain LO particle characteristics. Total explosive mass recovery (19–55%) and spatial distribution (0->20 m) varied significantly both between munitions and between replicate LOs of the same munition. The median particle size (0.27–3.99 mm) varied with total mass recovery. In general, LO particles coarsened, and total mass deposition rates decreased logarithmically, with increasing distance from the initiation point.

14 Apr 2023

Live-Fire Validation of Command-Detonation Residues Testing Using an 81 mm IMX-104 Munition

Abstract: Postdetonation energetic residues can have environmental impacts that present a risk to military training-range sustainment. As munitions with new explosive formulations are developed and fielded, quantitative methods for assessing their residues are needed. Command detonation (i.e., static firing) allows residue testing to occur early in the acquisition process; however, its representation of live-fire residue production is uncertain due to differences in the initiation mechanism and cartridge orientation. This study aims to validate residue testing by command detonation through statistical comparison of residue deposition rates between live fire and command detonation. Live-fire residues were collected from fourteen 81 mm IMX-104 mortar cartridges fired onto snow, and deposition rates were compared with previous command-detonation tests of the same munition. Average live-fire deposition rates were 8000 mg NTO (3-nitro-1,2,4-triazol-5-one), 60 mg DNAN (2,4-dinitroanisole), 20 mg RDX (1,3,5-trinitroperhydro-1,3,5-triazine), and 2 mg HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane) per cartridge. Compared to command detonation, live fire of the study munition produced significantly greater residues of NTO (p < 0.0001) and RDX (p = 0.01) but not DNAN (p = 0.067). Although absolute deposition rates of some IMX-104 compounds differed, command detonation was successful at predicting the order of magnitude of each IMX-104 compound for the studied 81 mm munition.