Overpressure Characteristics of Shock Waves Generated by Underwater Two-point Explosion from Aluminized Explosives

Multiple-explosion-source shock waves are one of the typical load types in underwater multipoint explosions. However, the associated working conditions often require the use of a large-scale three-dimensional computing domain for simulation, resulting in a significant calculation workload. Based on the existence of bubbles in the explosion products and the secondary energy release process of aluminized explosives, the linear superposition principle cannot accurately describe the laws of multi-point explosion loads. This research focused on the overpressure characteristics of the shock waves generated by the underwater two-point explosions of a typical polymer-bonded aluminized explosive using testing and simulation methods. The results indicate that the time history curves of overpressure obtained using different artificial viscosity values in different time periods are in good agreement with test curves. The error of multi-peak overpressure is typically below 15%. However, the time history curves of overpressure do not exhibit a low-amplitude discontinuous peak after the main shock wave peak. The reasons for this phenomenon are discussed in this paper. Such peaks are thought to be formed by aluminum particles reacting with surrounding material inside a shock wave. Additionally, the time history curves of the shock waves generated by the explosion of a single charge and two charges of the same mass are compared. Finally, the characteristics and differences of the time history curves of overpressure at 0°, 45°,and 90° are analyzed in detail. The research presented in this paper can provide a basis for the subsequent establishment of an underwater multipoint explosion load prediction model.