Numerical calculation of reflection overpressure distribution characteristics of small equivalent explosives at close range

How to determine the distribution of shock wave overpressure load on small equivalent explosives acting on close-range structures has always been a research hotspot in the field of protective engineering. This article establishes a two-dimensional axisymmetric calculation model for small equivalent spherical explosives based on LS Present. Verify the accuracy of the numerical calculation model through close-range explosion experiments and comparison with the Kingery Bulmash empirical formula. Based on the peak value of positive reflection overpressure, the reflection overpressure of different oblique reflections on a rigid wall was normalized, taking into account the effects of other charges (0.5 kg, 1 kg, and 2 kg) and different incident angles (0 ° to 60 °). The influence of Mach’s reflection on the distribution of reflection pressure on a rigid wall was analyzed. In addition, the research results indicate that under the same scaled distance, the normalized reflection overpressure distribution on the rigid surface tends to be consistent after explosions of 0.5kg and 1kg charges at the same proportional distance, while the normalized reflection overpressure during the 2kg charge explosion process deviates due to the influence of detonation products, especially when the incident angle is less than 8 °. Finally, the curve of the rigid wall reflection coefficient concerning the incident angle was obtained under different ratios of detonation distances. This study reveals the distribution pattern of reflected overpressure on rigid walls under close-range explosions, which can provide a reference for the distribution and data analysis of shock wave overpressure in small equivalent near-ground experiments.