This study presents an investigation into shock-induced exothermic reactions within three distinct aluminum-based energetic mixtures: aluminum/sulfur (Al/S), aluminum/copper oxide (Al/CuO), and aluminum/polytetrafluoroethylene (Al/PTFE). A challenge in current modeling efforts is accurately capturing the complex physical and chemical coupling under extreme loading, especially the influence of rapidly forming gaseous products in Al/PTFE mixtures on material integrity. To address this, a wide-range numerical model based on the Smoothed Particle Hydrodynamics (SPH) method was developed. This mesh-free approach manages large deformations and incorporates elastic-plastic flow, heat transfer, component diffusion, and chemical kinetics simulated using both zero- and first-order reaction schemes, favoring the latter for surface-reaction mechanisms. The proposed model takes into account gaseous reaction products, specifically aluminum fluoride (AlF3) to assess their impact on ampoule fracture dynamics. Numerical simulations, validated against experimental data, demonstrated that reaction rate, local pressure, and temperature are the primary controlling factors governing energy release and structural response. Comparative analysis revealed that although Al/CuO initiates reaction more readily (lower critical pressure/temperature), the Al/S mixture exhibits superior overall reaction efficiency under shock-wave loading, highlighting the significance of post-initiation kinetic factors. Furthermore, simulations using the conical ampoule geometry confirmed its effectiveness in generating a continuous pressure gradient, enabling systematic characterization of pressure-dependent reaction kinetics. This validated SPH model provides a powerful and predictive tool for understanding the complex behavior of energetic materials under shock-wave loading and aids in optimizing material composition for desired performance characteristics.
Ivanova et al. (Thu,) studied this question.