Temporal scale bridging in multiscale modeling of reactive RDX
The finite element modeling of macro-scale loads on energetic materials serves as an interesting case study in the necessity of multiscale methods. In our modeling of cyclotrimethylenetrinitramine (RDX), molecular simulations are required to capture the complex mechanochemical coupling at the micro-scale, which can occur on time scales of picoseconds. This coupling is such that the mechanical deformation and its rates affect the details of the chemistry, and in turn, the chemistry influences the continuum-scale deformation via the equation of state, evaluated at every continuum time step. To bridge such disparate temporal scales, we employ 1) direct coupling of molecular simulations via a novel hierarchical multiscale (HMS) framework and 2) a geometry-informed surrogate model capable of capturing the detailed chemistry with significantly lower computational cost, allowing for some of the first feasible large-scale simulations of reactive RDX from first principles. We compare the efficacy of these models in simulating flyer plate-impact, scaled thermal explosion (STEX), and slow cookoff experiments.
IMPACT
Accomplishment: Developed fast and accurate physical models of reactive energetic materials; Result: On the order of 1 million times computational speedup AND more detailed physics - Enables simulations for eventual use in designing explosives with improved safety and performance.
PRESENTER
LoGrande, Kevin
kevin.a.logrande.civ@army.mil
310-994-0549
DEVCOM Army Research Laboratory
CO-AUTHOR(S)
Crone, Joshua
joshua.crone.civ@army.mil
Leiter, Kenneth
kenneth.w.leiter2.civ@army.mil
Knap, Jaroslaw
jaroslaw.knap.civ@army.mil
CATEGORY
Comp Chemistry & Materials
SECONDARY CATEGORY
Surrogate Modeling for HPC
SYSTEM(S) USED
nautilus, narwhal, ruth, raider