Heterogeneous thermo-mechanical behavior and hot spot formation in RDX-estane energetic aggregates

Hot spot formation has been investigated in energetic aggregates with a viscoelastic binder and crystalline grains that has been subjected to dynamic thermo-mechanical loading conditions. A dislocation-density based crystalline plasticity, finite viscoelasticity, and specialized finite-element formulations were used to predict hot spot formation due to dynamic thermo-mechanical loading conditions in RDX-estane energetic aggregates. The interrelated effects of grain boundary (GB) misorientations, porosity, grain morphology, dislocation densities, polymer binder relaxation, and crystal-binder interactions were coupled with adiabatic plasticity heating, thermal decomposition, viscous dissipation heating, and thermal conduction to analyze aggregate behavior and hot spot formation. The predictions indicate that hot spot formation occurs when temperatures become unbounded in localized regions at the peripheries of RDX crystals where RDX-estane interfacial incompatibilities result in crystal sliding and localized plastic deformation at RDX crystal edges and interfaces.