Statistical Characterization of Thermoelastic Internal Stress in TATB-Textured PBX via Computational Micromechanics

TATB (1,3,5-triamino-2,4,6-trinitrobenzene) crystals exhibit strong thermoelastic anisotropy, making crystallographic texture a key factor in the thermal-stress response of TATB-based polymer-bonded explosives (PBXs). In this study, computational micromechanics combined with statistical analysis is used to quantify thermal-expansion-induced internal stresses in TATB-textured PBXs at the mesoscale. The results show that the spatial distribution of internal stress is strongly influenced by grain misorientation between neighboring grains, with larger misorientations leading to more severe stress concentrations. Statistical analysis further reveals that the internal stress distributions are generally asymmetric and unimodal. As texture intensity increases, the probability density peak rises, whereas both the mode stress and the average stress decrease. The maximum-to-minimum ratios of these three statistical characteristics reach up to 5.8, 8.9, and 6.1, respectively, indicating that texture intensity can regulate the stress field over a broad range. Gaussian mixture modeling is further employed to characterize the probability distributions of three stress measures. The distribution of maximum principal stress can be adequately described using two Gaussian components, whereas the von Mises and Tresca stress distributions require three components. These findings provide a quantitative basis for understanding and mitigating thermoelastic internal stress in PBXs through texture tailoring.