Modeling heterogeneous energetic materials at the mesoscale

The mesoscopic processes of consolidation, deformation, and reaction of shocked porous energetic materials are studied using shock physics analysis of impact on an ensemble of discrete "crystals". This work provides a foundation for improving our understanding of the processes at the mesoscale to advance continuum-level models for energetic material performance prediction and safety assessment. Highly resolved, three-dimensional numerical simulations indicate that rapid deformation occurs at material contact points, producing large amplitude fluctuations of stress that persist over several particle diameters. Localization of energy produces "hot-spots" due to shock focusing and plastic work near internal boundaries as material flows into interstitial regions. Numerical simulations indicate that "hot-spots" are strongly influenced by multiple crystal interactions. Chemical reaction processes also induce multiple wave structures associated with particle distribution effects. This study provides new insights into the micromechanical behavior of heterogeneous energetic materials, strongly suggesting that important statistical information associated with initiation and sustained reaction in shocked heterogeneous energetic materials may be embedded in fluctuating states that are distinctly different than the single shock jump descriptions traditionally used in continuum level models. (C) 2002 Elsevier Science B.V. All rights reserved.