  High energy materials such as polymer bonded explosives are commonly used as
propellants. These particulate composites contain explosive crystals suspended
in a rubbery binder. However, the explosive nature of these materials limits
the determination of their mechanical properties by experimental means.
Therefore micromechanics-based methods for the determination of the effective
thermoelastic properties of polymer bonded explosives are investigated in this
research. Polymer bonded explosives are two-component particulate composites
with high volume fractions of particles (volume fraction $>$ 90%) and high
modulus contrast (ratio of Young's modulus of particles to binder of
5,000-10,000). Experimentally determined elastic moduli of one such material,
PBX 9501, are used to validate the micromechanics methods examined in this
research. The literature on micromechanics is reviewed; rigorous bounds on
effective elastic properties and analytical methods for determining effective
properties are investigated in the context of PBX 9501. Since detailed
numerical simulations of PBXs are computationally expensive, simple numerical
homogenization techniques have been sought. Two such techniques explored in
this research are the Generalized Method of Cells and the Recursive Cell
Method. Effective properties calculated using these methods have been compared
with finite element analyses and experimental data.
