The dynamics of explosion and its use

TL;DR: In this article, the shape of spherical and cylindrical charges has been investigated and the expected change of the pressure field in the median plane of spherical charges was observed, directly linked to the L/D ratio.

Abstract: Linear charges are widely employed in military demining operations and civilian blasting engineering. Current research on blast load distribution from linear charges primarily focuses on underwater or free-air environments with limited aspect ratios. The surface load distribution generated from high-aspect-ratio linear charges in ground explosion remains unexplored. In this paper, an experimental investigation on ground explosions of linear charges with an aspect ratio of 100 was conducted. Then, a numerical model was developed to reproduce the detonation process of linear charges on the ground. The interaction between blast wave and the ground, the temporal evolution patterns of shock wave fronts, and surface overpressure distribution characteristics were investigated, as well as the effects of aspect ratio and initiation methods on surface overpressure distribution. A calculation model for overpressure distribution in the radial region of linear charge was developed. The findings reveal that the ground has an enhanced effect on the propagation of blast wave. The wave front of linear charge is composed of ellipsoidal wave fronts at both ends and a conical wave front enveloping the charge axis. The peak overpressure initially increases, then plateaus, and ultimately decays along the charge axis. In end regions, the peak overpressure decreases initially then increases with azimuth angle. Under constant linear density, the surface overpressure increases and then gradually stabilizes with increasing linear charge aspect ratio. Among the three initiation methods, central initiation exhibits the largest azimuth angle range of the high peak overpressure zone, followed by end initiation, and both-end initiation shows the smallest range.

TL;DR: This study experimentally and numerically investigates local damage to reinforced concrete columns under rectangular charges, developing a theoretical model that predicts damage with improved accuracy, considering factors like concrete strength, standoff distance, and axial load.