  In this paper is presented a new single crystal plasticity model with
yielding accounting for the tetragonal symmetry of molecular energetic
crystals. This new tetragonal yield criterion has been developed using
representation theorems for anisotropic tensor functions. It is defined for any
type of loadings and depends on the characteristics of the tetragonal lattice
(c/a ratio). It involves three independent plastic anisotropy parameters that
can be expressed analytically in terms of the uniaxial yield stresses along
four crystallographic directions. Illustration of the capabilities of this
model is done for a pentaerythritol tetranitrate (PETN) crystal. Moreover, we
present finite-element meso-scale simulations of the response of a polymer
bonded explosive for which the behavior of the constituent energetic molecular
crystals is described with an elastic/plastic model with yielding governed by
the new single-crystal tetragonal criterion. The simulation results provide
insights into the role played by the anisotropic crystalline plasticity and
interactions between crystals on the thermo-mechanical response under dynamic
compression of the PETN-based polymer bonded explosive (PBX) aggregate.
