Propagation Law of Blast Wave in a Flat Large Space

Abstract:

In order to study the propagation law of blast shock wave in a flat large space such as underground parking lot， a 2D axisymmetric analysis model was established using AUTODYN software. The propagation characteristics of shock wave after 8 different masses of TNT detonated at the ground in the middle of the flat large space were analyzed. By combining the propagation cloud picture of blast shock wave and the pressure time history curve of some gauges， it is found that the shock wave will form multiple Mach waves in the propagation process， and the height of the Mach stem of the first Mach wave can reach the space net height. The height of the Mach stem of the subsequent Mach wave is small， but the propagation speed is fast， and it will eventually catch up with the first Mach wave， and converge with it. The peak overpressure at the junction is increased compared with other positions of the Mach stem. As the propagation distance increases， the influence of subsequent Mach wave waves on the first Mach wave decreases. The formula for determining the horizontal position of the critical point where the peak overpressure of the Mach wave front is constant and the corresponding maximum peak overpressure value according to the scaled clear height， and the formula for determining the average value of the maximum peak overpressure according to the plane scaled distance are given.