New developments of HEMSim: a computational treatment for aluminized highly energetic materials applied to rock blasting

The purpose of this study is to assess the feasibility of using the ideal detonation code HEMSim to calculate detonation parameters of non-ideal explosives, including aluminized formulations, for subsequent use in hydrodynamic simulations. HEMSim is based on the Chapman-Jouguet (CJ) theory and is not inherently designed to model non-ideal explosives or the delayed energy release associated with aluminum reactions. This limitation complicates the prediction of detonation parameters and Jones-Wilkins-Lee (JWL) equation of state (EoS) parameters required by many blast simulation tools. To address this issue, the HEMSim model was adapted to incorporate a user-defined degree of aluminum reaction completion during detonation, enabling partial aluminum reactivity to be considered. Detonation parameters and JWL EoS parameters were calculated for emulsion explosives containing 0-20% aluminum powder. A series of cylinder tests was conducted to obtain experimental data, from which JWL parameters were derived. These parameters, along with those calculated numerically, were implemented in LS-DYNA hydrodynamic simulations, and simulated cylinder wall velocities were compared with experimental results for validation. The approach was further demonstrated by simulating explosive-rock interaction in a granite specimen. The modified HEMSim approach provides detonation and JWL parameters that yield good agreement between simulated and experimentally measured cylinder wall velocities. The inclusion of aluminum significantly influences detonation behavior and results in increased damage to rock in numerical simulations. The proposed methodology enables practical prediction of detonation parameters for non-ideal and aluminized explosives using an ideal detonation code. This approach is suitable for hydrodynamic simulations requiring simple JWL inputs and supports the design of more efficient, predictable, and cost-effective blasting operations, particularly when aluminum-containing explosives are employed.