Effect of Initial Temperature on Pore Collapse Hot Spots in TATB High Explosive

ABSTRACT The shock initiation threshold of insensitive high explosives (IHEs) based on TATB (1,3,5‐triamino‐2,4,6‐trinitrobenzene) is known to exhibit a complicated dependence on initial temperature, but the underlying mechanism is not well understood because of multiple plausible ways in which the temperature might impact hot spot formation processes that govern initiation. To this end, we perform non‐reactive all‐atom shock simulations of pore collapse in a TATB crystal with a pre‐defined void and analyze resulting hot spot structures for different initial temperatures, both colder and hotter than the ambient level. We represent hot spots as 2D images (i.e., distribution fields) of important energetic and structural parameters, including temperature, temperature rise, intramolecular strain energy, and molecular rotational disorder. To decipher if the initial temperature has any significant effect on hot spot structure beyond normal stochastic variations, we apply a recently developed principal‐component‐based image distinguishability analysis test. We find that for fixed shock strength and orientation relative to the crystal, the spatial localization of thermal and nonthermal energy in hot spots formed in initially hot and cold TATB crystals is statistically indistinguishable from the room‐temperature baseline in most cases. However, the simulations also provide tentative evidence that the shear band ignition mode in TATB may depend on initial temperature through modulation of the density of the band network. These results are expected to help guide treatments of variable initial temperature in macroscale IHE detonation models that are based on the hot spot concept.