Microstrucutral Modeling of Hot Spot and Failure Mechanisms in RDX Energetic Aggregates

Abstract

Hot spot formation and failure mechanisms, such as dynamic fracture and shear strain localization, for RDX (cyclotrimethylene trinitramine)-polymer binder aggregates were investigated for dynamic thermo-mechanical loading conditions. A formulation based on a dislocation-density based crystalline plasticity and a finite viscoelasticity framework was coupled to a microstructurally-based dynamic fracture nucleation and propagation method, and it was used to investigate interrelated high strain-rate failure modes in RDX-polymer binder energetic aggregates. The effects of grain boundary (GB) misorientations, porosity, grain morphologies, dislocation densities, and crystal-binder interactions were coupled with adiabatic plasticity heating, thermal decomposition, thermal conduction, and dissipated heat to predict and understand hot spot formation for a PCTFE (Polychlorotrifluoroethylene) polymer binder. The validated predictions indicate that hot spots were induced by inelastic deformation modes, which resulted in unbounded temperatures due to localized plasticity and thermal decomposition at the peripheries of the voids. Viscous dissipation, due to the estane polymer binder, where the operating temperatures were above the glass transition temperature, resulted in RDX crystal interactions due to hydrostatic compression of the polymer binder. This hydrostatic compression constrained the polymer binder interfaces, which enhanced RDX inelastic deformation modes and resulted in and accelerated hot spot formation at the RDX crystal peripheries in the interfacial regions between the estane binder and the RDX crystals. The effects of dynamic crack nucleation and propagation were also investigated in energetic aggregates subjected to high strain rate loading conditions.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 2014
Accession Number
ADA627018

Entities

People

  • Darrell A. Labarbera

Organizations

  • North Carolina State University

Tags

Communities of Interest

  • Biomedical
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Boundaries
  • Conduction (Heat Transfer)
  • Energetic Materials
  • Engineering
  • Explosives
  • Failure Mode And Effect Analysis
  • Finite Element Analysis
  • Glass Transition Temperature
  • Grain Boundaries
  • Materials
  • Materials Laboratories
  • Materials Science
  • Mechanics
  • Molecular Dynamics
  • Plastic Properties
  • Rdx
  • Transition Temperature

Fields of Study

  • Materials science

Readers

  • Materials Science and Engineering.
  • Polymer Science and Engineering.
  • Structural Health Monitoring of Composite Structures.