Numerical Simulation of the Elastic–Plastic Ejection from Grooved Aluminum Surfaces Under Double Supported Shocks Using the SPH Method

The ejection of disturbed surfaces under multiple shocks is a critical phenomenon in pyrotechnic and inertial confinement fusion. In this study, the elastic–plastic ejection from grooved aluminum surfaces under double supported shocks was investigated using the SPH method. A spallation region developed at the bottom of the bubble during the first ejection, and the subsequent second ejection comprised three distinct components: low-density; high- and medium-velocity ejecta; and high-density, low-velocity ejecta. Recompression of the spallation material generated high- and medium-velocity ejecta, resulting in a limited second ejecta mass. The significant increase in the defect area of the bubble and the convergence of the first ejecta generated low-velocity ejecta, resulting in a substantial increase in the second ejecta mass. The shock pressure threshold required for the second ejection was significantly reduced compared with the first ejection. The second ejecta mass increased with shock pressure, but the increase rate gradually decreased, primarily affecting the low-velocity ejecta. The time interval between shocks primarily influenced the second ejection, driven by the evolution of the spallation region at the bottom of the bubble and the convergence of the first ejecta. The second ejecta mass increased and asymptotically approached a constant value with increasing time intervals.