Chapter 19: Implementation of Hvrb in LS-DYNA and Application to Detonation in Hemispherical Charges in Ideal Explosives

The modelling of energetic materials is usually performed within an Eulerian framework, inherently well suited to simulate fluid-like behaviour of the reaction products and the propagation of pressure waves in the surrounding fluid media (e.g. air or water). However, the Lagrangian framework becomes more attractive in the effort to reproduce the unreacted mechanical response of the material, especially as we move towards trying to capture better the response of damaged explosives. In this paper the implementation of the History Variable Reactive Burn (HVRB) model in the Lagrangian explicit software LS-Dyna is presented. The HVRB reaction rate parameters are verified against simple ratestick tests before being used to simulate the detonation of hemispherical charges from an ignition point located at the pole of the hemisphere. The numerical results are directly compared against high-speed video from the experimental tests, illustrating reasonable agreement given the simplicity of the HVRB formulation. This paves the way for developing deeper understanding by incorporating more complex reactive burn models, e.g. Damage Initiated Reaction (DMGIR), which can consider the role of mechanically induced damage upon the response of explosives.