Multi-Scale Simulation Framework for Heterogeneous Energetic Materials

ABSTRACT: Designing propulsion devices and munitions for precise operational performance demands control and manipulation of energy released by explosive materials. It is well recognized that the initiation of energetic materials in explosives applications depends sensitively on hot-spots that originate from various heterogeneities at the meso (particle)-scale such as voids, defects, dislocations and grain boundaries. The proposed work will develop a computational tool (SCIMITAR3D) to conduct sophisticated and realistic computational modeling of the multi-scale thermo-mechanics of heterogeneous energetic materials. SCIMITAR3D will be demonstrate 3-dimensional simulations of macro-scale and meso-scale reactive dynamics of typical HE mixtures under a range of loading conditions and for varying explosive formulations. Key aspects of modeling meso-scale energy localization mechanisms, such as crystal-crystal contact, friction and damage evolution and state-of-the-art reactive kinetics models will be put in place in a portable, scalable large scale simulation code. Techniques to bridge meso- and macro-scale models in a full multi-scale simulation capability will be selected and established in Phase I. Phase I will lay the foundations for state-of-the-art macro- and meso-scale energetic material simulations; these capabilities will be extended in Phase II to perform large scale multi-scale simulations of energetic material response to shock loading in a high performance computing environment.; BENEFIT: The proposed work will bring in state-of-the-art modeling tools and improved meso-macro scale connections in a multi-scale model framework. Uncertainties will become quantified in this multi-scale setting as the Dynamic Kriging approach used in metamodeling lends itself to uncertainty and sensitivity analysis. Due to these improvements the software produced will gain foothold amongst modelers and designers of devices that use heterogeneous materials. The broad appeal of the proposed work is that the basic framework developed here will be applicable to a wide range of problems involving meso-scale heterogeneities as well and will benefit not only the Air Force but other DoD and non-DoD agencies. For example, Streamline Numerics is engaged in projects with NASA on design of combustors where spray formation and combustion is being modeled. The techniques for scale bridging and metamodeling developed here will be applicable to those systems as well. Thus, the proposed work will lead to a broad range of contributions, specifically a design tool for use by DoD agencies and general techniques that have broad application in multi-scale modeling of heterogeneous materials. The commercial value of the tool developed will be enhanced by the wide applicability of the processes and algorithms embedded in the proposed work. The geometries that are input to the tool can come from a wide range of imaging modalities, such as X-ray CT, MRI, still images, or video, provided that these geometries can be converted into levelsets by a suitable image processing software. The applications of the mesoscale simulation techniques to be developed here are multifarious, including groundwater and pollutant transport, oil recovery, seismology, CO2 sequestration, biomedical applications (organ systems, transport in the vasculature and microvasculature) etc.. Therefore, the software has potential for applicability and commercial use in a wide range of fields involving scientific research, design, analysis and prediction.