Critical velocities for deflagration and detonation triggered by voids in a REBO high explosive

Conference · Fri Jan 01 04:00:00 EST 2010

OSTI ID:992167

Herring, Stuart Davis ^[1]; Germann, Timothy C ^[1]; Jensen, Niels G ^[1]

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1. Los Alamos National Laboratory

The effects of circular voids on the shock sensitivity of a two-dimensional model high explosive crystal are considered. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. The probability of initiating chemical reactions is found to rise more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void with radius as small as 10 nm reduces the minimum initiating velocity by a factor of 4. The transition at larger velocities to detonation is studied in a micron-long sample with a single void (and its periodic images). The reaction yield during the shock traversal increases rapidly with velocity, then becomes a prompt, reliable detonation. A void of radius 2.5 nm reduces the critical velocity by 10% from the perfect crystal. A Pop plot of the time-to-detonation at higher velocities shows a characteristic pressure dependence.

• Research Organization: Los Alamos National Laboratory (LANL)
• Sponsoring Organization: DOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 992167
• Report Number(s): LA-UR-10-01466; LA-UR-10-1466
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
CHEMICAL EXPLOSIVES
CHEMICAL REACTIONS
CRITICAL VELOCITY
EXPLOSIONS
PISTONS
PRESSURE DEPENDENCE
PROBABILITY
SENSITIVITY
VELOCITY