Meshfree Modelling of Coupled Thermal-Mechanical-Chemical Phenomena in Energetic Aggregates

  • Brown, Judith (Sandia National Laboratories)
  • Beckwith, Frank (Sandia National Laboratories)
  • Wolf, Ki Tae (Sandia National Laboratories)
  • Clemmer, Joel (Sandia National Laboratories)

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Energetic aggregates are a complex class of materials that produce exothermic chemical reactions with varying degrees of violence when exposed to dynamic mechanical impacts and/or elevated temperature environments. The resulting energetic event emerges from a sequence of coupled mechanical, thermal, and chemical processes that are often accompanied by large deformations and pervasive material fracture. We present a multi-physics conforming reproducing kernel particle method that has been developed to overcome the challenges associated with traditional finite element modelling in this large deformation regime. The method performs loosely coupled solves of the material momentum balance (stress and strain), energy balance (temperature), and temperature-dependent chemical reaction rates and exhibits excellent numerical robustness. This computational framework is used to study the response of energetic aggregates to various insults and provide new predictions of the coupled thermo-mechanical events leading to chemical reaction. In addition to energetic materials, the methods show promise for modelling many applications where large-deformation, thermo-mechanical material behaviour plays a key role.