Effects of reaction kinetics models on macro-scale sensitivity predictions for a wide class of energetic materials

The sensitivity of heterogeneous energetic materials (HE) depends on their chemical (molecular) and physical (micro-) structure. For a wide range of energetic materials, the primary energetic components are organic CHNO crystals. The overall macroscopic sensitivity of HEs depends on a complex coupling of the molecular reaction chemistry and microstructural dynamics, due to the localization of energy at hotspots in the microstructure. Reactions triggered at hotspots advance into the unreacted sample, leading to shock-to-detonation (SDT) scenarios. In this work, we perform multi-scale simulations to investigate the effect of uncertainties in the chemical kinetics parameters for the decomposition of the HE material on the rate of deposition of energy at the macro-scale. Ensembles of high-resolution reactive void collapse simulations are performed by varying the global Arrhenius parameters (representing a wide class of HE materials, ranging from insensitive TATB to highly sensitive PETN) to construct meso-informed surrogate models for energy localization. Then macro-scale computations of shock-to-detonation transition are performed using the meso-informed Ignition and Growth (MES-IG) model. The performance of the HE at the macro-scale is evaluated via the critical energy required for initiation in the Walker-Wasley/James space. The predicted critical energy envelopes are compared with experimental data. The results quantify the effects of uncertainties in the chemical kinetics parameters on the macro-scale sensitivity predictions. This study will guide the development of reaction kinetics models to reliably predict macro-scale sensitivity of a wide range of CHNO materials.