Effects of Crystal Morphology on Impact Sensitivity of LLM-105 Based Explosives

LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide) is an insensitive high explosive which has performance between that of HMX and TATB. The LLM-105 crystal morphology are dependent on its synthetic, recrystallization and processing history. It is thermally stable and fairly insensitive to shock, spark and friction, but the impact sensitivity depend on the crystal morphology. A dislocation based viscoplasticity model is developed for LLM-105 crystal, which accounts for the dislocation evolutions in crystal interiors and crystal walls and strain-rate dependent work hardening. Three different crystal morphologies (Cubic, Icosahedral, Rodlike) of LLM-105 based explosives models were constructed and subjected to an impact velocity of 200 m/s. Effects of crystal morphology on thermo-mechanical behavior and impact sensitivity of LLM-105 based explosives were analyzed. Dislocation density of both crystal interiors and crystal walls in the rodlike explosive increases slower than that in the cubic and icosahedral explosives. The lowest accumulated shear strain and the temperature rise indicate the rodlike explosive is the least sensitive.