Effect of particle size distribution of HMX and initial temperature on mechanical and performance properties of pressable plastic bonded explosives

This study examines the impact of mass percentages of fine and coarse particles in PBX compositions on mechanical properties, performance, and sensitivity, as well as the influence of temperature on these factors. The findings indicate that the density measurement test alone is insufficient to definitively identify voids in pressed PBXs, and that the mass percentages of fine and coarse particles do not significantly affect impact and friction sensitivity. Additionally, a decrease in packing density correlates with an increase in linear thermal expansion coefficients, as shown by TMA tests. Compression tests reveal that mechanical properties (stress and strain) decrease with increasing mass percentages of coarse particles, with variations due to density changes at different temperatures. Furthermore, higher mass percentages of fine or coarse particles lead to reduce in packing density and performance at ambient temperatures, while performance is significantly impacted by temperature variations as packing density decreases. Notably, as packing density approaches optimal levels the effect of temperature on performance diminishes. Overall, the study highlights that variations in particle mass percentages significantly influence mechanical properties and performance through changes in packing density, and that initial temperature of PBXs result in notable variations in performance and mechanical properties due to the presence of voids.