Micromechanical models and experiments for diffractive elastic constants of TATB-based polymer-bonded explosives

Abstract

TATB-based polymer-bonded explosives (PBXs) exhibit intricate internal stress distributions due to crystal anisotropy. When diffraction techniques are employed to measure these internal residual stresses, it is critical to identify the discrepancy between the diffraction elastic constants (DEC) of particular crystal planes of a TATB-based PBX and the macroscopic elastic constant of the PBX. This study introduced various micromechanical models to describe the mechanical behavior of TATB-based PBXs, as well as assessing their accuracy in predicting the elastic properties of the PBXs and calculating the DECs of different crystal planes. Using in situ tensile experiments, this study obtained accurate DECs of the crystal plane of TATB-based PBXs and revised the residual stress measurements of the PBXs. The comparison between experimental results indicates that the two-phase and double-inclusion micromechanical models proposed in this study exhibit higher precision in predicting both the quasi-static mechanical properties of the PBXs and the DECs of the crystal plane. Furthermore, the DECs of the PBXs with high volume fractions of TATB are close to those of pure TATB crystals. Based on the established double-inclusion model, it can be inferred that the DECs of different crystal planes vary as a function of the TATB volume fraction. This study lays the foundation for profound analyses of the mechanical characteristics of TATB-based PBXs using diffraction techniques.