Reverse‐Impact Method With Multi‐Window Velocimetry for LLM‐105: Determining Unreacted Shock Hugoniot and Mie–Grüneisen Equation of State

Reverse‐impact method with multi‐window (polymethyl methacrylate, lithium fluoride, and sapphire) is developed to resolve chemical reaction interference in unreacted Hugoniot measurements of explosives. The technique isolates unreacted states of LLM‐105 (2,6‐diamino‐3,5‐dinitropyrazine‐1‐oxide) explosive across 1.63–12.08 GPa for 1.809 g/cm 3 and 1.836 g/cm 3 densities, achieving Hugoniot data with ≤ 5% relative uncertainty. Concurrently, acquired waveforms enable reactive burn calibration through analysis of post‐shock reaction growth. Analysis exhibits LLM‐105's Grüneisen parameter as a function of specific volume, motivating a density‐generalized Mie–Grüneisen equation of state via Snowplough model integration. This framework enables to predict compression response of LLM‐105 for arbitrary densities across 1.809–1.910 g/cm 3 . The method establishes an advanced paradigm for characterizing energetic materials’ dynamic behavior under shock loading.