Exploring the mechanical behavior of polymer-bonded energetic materials under high pressure and shear
DOI: 10.1063/10.0007130
Exploring the mechanical behavior of polymer-bonded energetic materials under high pressure and shear lead image
Predicting the mechanical and physical properties of polymer-bonded explosives, or PBXs, is challenging, especially when anticipating their initiation upon impact. Malhotra et al. compared the deformation of a hydroxyl-terminated polybutadiene and sucrose energetic simulant at both large pressures and shear strain-rates.
Detonation in a PBX typically starts at local zones of high temperature called hotspots. Predicting the formation of these hotspots is inconsistent, especially in multiaxial high strain rate loading scenarios.
Examining the mechanical behavior of a PBX under impact, the authors developed a quantitative understanding of the loading conditions that could lead to hotspot formation within the composite. They observed that under higher pressures, polymer-bonded simulants can withstand larger stresses and fail at larger critical strains.
“Interestingly, such a pressure sensitivity is expected to be derived from the soft elastomeric phase, which makes up for only 10% of the composite,” said co-author Pinkesh Malhotra.
PBXs are widely used in civil and military applications, including mining and construction, and as solid fuel in rocket propellants. Designing safe energetic materials is crucial for their deployment in these practical situations.
The authors stress future studies should focus on pressures greater than 10 gigapascal.
“It is expected the elastomeric phase of the composite no longer remains the softer phase, which would result in a change in deformation and energy dissipation mechanisms at the microstructural scale. However, these expectations need to be experimentally verified,” said Malhotra.
Source: “Dynamic shearing resistance of a polymer-bonded energetic simulant: Composite of sucrose and hydroxyl-terminated polybutadiene (HTPB),” by Pinkesh Malhotra, Tong Jiao, Rodney James Clifton, and Pradeep R. Guduru. Journal of Applied Physics (2021). The article can be accessed at https://doi.org/10.1063/5.0056684 .
