Peridynamic investigation of dynamic damage behaviors of PBX confined in spherical steel shells

The bond-based peridynamics (PD) modeling is employed to investigate the dynamic damage response of polymer bonded explosive (PBX) confined in spherical steel shells under impact loading. The softening behavior of PBX is reasonably well captured by a bilinear constitutive model defined for PD bonds. The simulation results indicate that the damage behaviors of PBX depend on the impact speed. At the low impact speed, the damage of PBX is characterized by the absence of the longitudinal cracks. In contrast, the presence of longitudinal cracks leads to the serious damage of spherical shell of PBX at the high impact speed. The dynamics of stress wave such as reflection and transmittance at the solid boundary are analyzed based on the stress wave theory, providing a comprehensive understanding of how the external confinement affects dynamic damage response of PBX. The effects of Young's modulus of steel shells on the damage of PBX are also examined. The simulation results illustrate that the damage of PBX depends on the property of the external steel shell, but is almost independent on the property of the internal steel shell. These interesting phenomena can be well understood based on the dissipation of impact energy of the flyer. The presented computational results offer rigorous basis for the full understanding of the dynamic damage response of PBX in the more complicated confinement conditions.