Forging of Hierarchical Multiscale Capabilities for Simulation of Energetic Materials

Abstract

We present new capabilities for investigation of microstructure in energetic material response for both explicit large‐scale and multiscale simulations. We demonstrate the computational capabilities by studying the effect of porosity on the reactive shock response of a coarse‐grain (CG) model of the energetic material cyclotrimethylene trinitramine (RDX), the non‐reactive equation of state for a porous representative volume element (RVE) of CG RDX, and utilization of available supercomputing resources for speculative sampling to accelerate hierarchical multiscale simulations. Small amounts of porosity (up to 4 %) are shown to have significant effect on the initiation of reactive CG RDX using large‐scale reactive dissipative particle dynamics simulations. Non‐reactive RVEs are shown to undergo a porosity‐dependent pore collapse at hydrostatic conditions, and an existing automation framework is shown to be easily modified for the incorporation of microstructure while retaining reliable convergence properties. A novel predictive sampling method based on use of kernel density estimators is shown to effectively accelerate time‐to‐solution in a multiscale simulation, scaling with free CPU cores, while making no assumptions about the underlying physics for the data being analyzed. These multidisciplinary studies of distinct yet connected problems combine to provide methodological insights for high‐fidelity modeling of reactive systems with microstructure.

Modeling and Simulation of RDX Powder Thermo‐Mechanical Response to Drop Impact

“…Commercially‐based DEM techniques [25–28] are powerful for their computational practicality in modeling macroscale particulate flow behaviors governed by the elastic or rigid body collisions of thousands of highly mobile particles. However, powdered EM materials have been shown to behave as highly plastic particles under drop hammer dynamic loads [14–29]. Modeling those types of impacts require that the plasticity of the particles be considered in the numerical treatment.…”

“…Over the past thirty years, a significant number of numerical studies have been devoted to modeling the initiation of heterogeneous solid explosives and propellants [15–17]. These numerical methodologies now extend into modern multiscale computational techniques that are leveraged on large‐scale computational systems [18–22]. Solid phase FEA simulations cannot reflect the influential role of the phenomena that occur as the EM response becomes dominated by phase changes.…”

Generalized Energy-Conserving Dissipative Particle Dynamics with Reactions

“…A plethora of discrete CG particle modeling studies of micro- and mesoscale phenomena can be found in the literature. Studies have been performed over an extensive scope of materials and applications, including the life sciences (proteins, colloidal suspensions, bio-membranes, and micelles), industrial applications (surfactants, asphaltenes, and viscoelastic fluids), defense applications (energetic material composites and liquid propellants), and novel materials (self-assembled block copolymers and nanoparticles). − …”

Generalized Energy-Conserving Dissipative Particle Dynamics with Mass Transfer. Part 1: Theoretical Foundation and Algorithm

“…A plethora of CG particle modeling studies of microscale phenomena can be found in the literature that exemplify the utility of CG approaches. Studies have been performed over an extensive scope of materials and applications, including, but not limited to, life sciences (proteins, colloidal suspensions, biomembranes, and micelles), industrial applications (surfactants, asphaltenes, and viscoelastic fluids), national defense applications (energetic material composites and liquid propellants), and novel materials (self-assembled block copolymers/nanoparticles). − …”