Modeling Impact Induced Damage and Ignition in Unconfined High Explosives*

We have recently conducted a series of tests in which unconfined explosive disks mounted

onto a polycarbonate plate are impacted at low velocities (15-40 m/s) by a rounded projectile.

We used high speed videography to record the impact event from the back side of the plate.

We observe the damage evolution prior to ignition, and monitor the velocities where ignition

occurs in different explosive formulations. We use these observations to inform the

development and calibration of the High Explosive Response to Mechanical Stimuli (HERMES)

explosive safety model [1]. In this work we assess the affects of various material parameters in

the HERMES model on the observed mechanical behavior, which includes dynamic fracture and

comminution. We calibrate our ignition model for comparison with low-velocity impact

ignitions in other, more confined geometries such as the Steven test.

[1] J. E. Reaugh, et al. “A Computer Model to Study the Response of Energetic Materials to a

Range of Dynamic Loads,” Propellants, Explosives, Pyrotechnics, 43(7), p. 703-720, 2018.