爆炸冲击波在扁平大空间内的传播规律

Propagation Law of Blast Wave in a Flat Large Space

摘要:

为研究爆炸冲击波在地下停车场等扁平大空间内的传播规律，采用AUTODYN软件建立了二维轴对称分析模型，分析了8种质量的TNT在扁平大空间中间位置地面处引爆后冲击波的传播特性。通过结合爆炸冲击波传播云图和部分测点的压力时程曲线，分析发现冲击波在传播过程中会形成多个马赫波，首个马赫波的马赫杆高度可以达到空间净高，后续马赫波的马赫杆高度较小，但传播速率大，最终会追上首个马赫波，并与其汇合，在汇合处峰值超压较马赫杆其他位置有所增加，随着传播距离的增加后续马赫波对首个马赫波的影响越来越小。给出了根据比例净高确定马赫波阵面峰值超压恒定的临界点水平位置和对应最大峰值超压值的计算公式，给出了根据平面比例爆距确定最大峰值超压平均值的计算公式。

关键词:爆炸;冲击波;扁平大空间;马赫波;超压峰值

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.

Key words:blast;shock wave;flat large space;Mach wave;overpressure peak