Impact and Detonation of COMP-B: An Example using the LS-DYNA EOS: Ignition and Growth of Reaction in High Explosives

The LS-DYNA keyword *EOS_IGNITION_AND_GROWTH_OF_REACTION_IN_HE provides the ability to model the ignition and growth of the reaction in high explosives via shock initiation from an impact or donor explosive. In this preliminary assessment effort, the experimental results for projectile impact on COMP-B of Almond and Murray (2006) are simulated. In addition to reporting their experimental results, the authors also reported numerical simulations results. Further, Urtiew et al. (2006) reported numerical simulation results for this set of experiments, using the same ignition and growth of the reaction in high explosives equation of state, Lee and Traver (1980,) implemented in LS-DYNA, but using a different explicit hydrocode. The experiments reported by Almond & Murray were for a blunt brass projectile impacting COMP-B without and with cover plates made from steel, aluminum and high density polyethylene. The critical impact speeds were in the range 950 to 1350 meters/second (2000 to 3000 miles/hour). Their numerical simulations used AUTODYN with the Lee and Tarver ignition and growth model. Similar experiments are reported by Lawrence et al. (2002 and 2006) which also included impact of COMP-B with steel cover plates by projectiles. This series of experiments considered different cover plate thicknesses, projectile nose shapes, and impact obliquity of the projectile. Critical impact speeds ranged from about 1050 to 1600 meters/second for the normal impact cases. The experimental configurations were simulated using the CTH (Hertel et al., 1993) code with the History Variable Reactive Burn (HVRB) explosive initiation model (Kerley, 1995). These experiments are not simulated in the present manuscript, but recommend to interested readers. In this manuscript the ignition and growth of the reaction in high explosives equation-of-state is introduced along with model parameters for COMP-B. Some comments are included in this section concerning alternative versions of these model parameters that are available in the literature. The manuscript focuses on the experimental data of Almond and Murray, their simulations results, the simulations results of Urtiew et al. and the present results, which make use of the relatively new LS-DYNA axisymmetric Multi-Material Arbitrary Eulerian Lagrange (MM-ALE) capability and thus serve as a post-test form of model validation.