تسجيل الدخول

تسجيل

Blast Pressure

المؤلف:  Max M. Houck، Jay A. Siegel

المصدر:  Fundamentals of Forensic Science

الجزء والصفحة:  p480-481

2026-08-22

30

Blast Pressure

Escaping gases can travel as much as 8000 miles per hour and exert hundreds of tons per square inch of pressure. This compresses the gases and the surrounding air. The wave that is created by this blast will shatter anything that gets in its way. The damage decreases with distance as the wave loses energy. As the blast wave travels away from the bomb seat, it creates a partial vacuum because the air itself has been displaced. When the blast wave dissipates, the vacuum must be filled. The compressed air and gases now rush back toward the bomb seat. This causes another blast effect, the negative pressure phase. This is not as powerful as the positive pressure blast phase but it is capable of doing additional serious damage to objects that have already been damaged by the initial blast. The two phases of a blast can be seen in Figure 1(a)–(d).

FIGURE 1 Positive and negative phases of blast pressure during an explosion. Note how the damage can be strewn around the site and cannot be explained by just the positive pressure phase. The negative pressure phase can cause considerable damage. (a) The scene before the blast; (b) the damage from the positive pressure phase; (c) the damage after the negative pressure phase; and (d) the scene after the explosion is over.