The thermochemical responses of shock loaded high explosive crystals are linked to localized mechanical dissipation through various inelastic deformation modes. While plastic deformation in crystalline explosives is sometimes mediated by dislocation glide, this mode can be hindered, leading to the activation of other mechanisms. Shear localization is often observed in molecular dynamic simulations, with behavior ranging from mild loss of crystalline order to catastrophic lattice failure. Conventional continuum modeling methods often exhibit mesh dependence when trying to model shear bands, thus necessitating formulations that can mitigate these effects. Through the introduction of a length scale (i.e., the shear band thickness) it is possible to improve the mesh convergence. Using this approach, we construct a material model that emulates the behavior of TATB crystals and study the effects of shear localization in response to dynamic loading conditions.
This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 (LLNL-ABS-798914).