Understanding the Deformation and Fracture Behavior of β−HMX Crystal and Its Polymer−Bonded Explosives with Void Defects on the Atomic Scale

The effect of the void defect on β−HMX−based polymer−bonded explosives (PBXs) for a comprehensive understanding of the deformation and fracture process is lacking. In this paper, the atomic scale model of the β−HMX crystal and its PBX is built using LAMMPS software to investigate the mechanical response under dynamic tensile conditions. The void defect considers both regular and stochastic distributions. The simulation concerns the deformation and fracture process with respect to the void size, void number, void spacing, and the stochastic characteristics. The tensile stress–strain relationship is obtained, and the fracture morphology is simulated well. The crack propagation is discussed in detail. Further, the fracture mode is compared between the single crystal and PBX. In addition, the characteristic defect parameter combines both the damage area and the void spacing, and it is used to predict the crack occurrence and propagation for the single crystal. However, for PBX, the interface between the crystal and binder determines the fracture process instead of the characteristic defect parameter.