Numerical analysis of the damage and failure behavior of polymer-bonded explosives using discrete element method

The mechanisms of crack initiation and propagation in polymer-bonded explosives (PBXs) are not clearly understood at present. In this study, the discrete element method is used to investigate the damage and failure behavior of PBX under quasi-static compressive and tensile loading. The real particle shapes and microstructure of the crystal are considered to establish the discrete element model. The results reveal that under quasi-static compressive loading process, tensile microcracks are predominant. Before the failure strain, microcracks are mainly distributed in the binder, and they tend to be more uniformly distributed at higher strain rates. During the quasi-static tensile loading, due to microcrack penetration, the propagation path of the principal crack is approximately perpendicular to the loading direction. The maximum contact force between the particles increases with the increase in the strain rate under the same loading condition, which tends to be uniformly distributed before the failure strain, while the contact force concentration phenomenon occurs after the failure strain due to damage. The simulation results show that the failure strain, compressive strength, damage path, and damage degree are all correlated with the strain rate. The predicted results are in good agreement with the previously reported experimental measurements and other numerical simulation results.