Brisance of explosive substances

BRISANCE OF EXPLOSIVE SUBSTANCES (EN: brisance of explosives, shattering effect; DE: Brisanz, Sprengkraft; FR: brisance des explosifs, pouvoir brisant; ES: poder rompedor de los explosives; RU: бризантность взрывчатых веществ) is the ability of the explosive substances to perform during the explosion the crushing of the environment within the immediate proximity near the charge (several radiuses of the charge).

As the result of the emergence of the detonation wave onto the surface of contact of the charge of explosive substances with the material, which is being destructed, there emerges within the environment the region of compression with the sharp increase of the density and temperature at the leading front edge. The magnitude of the maximal stresses, which are emerging during this process, depends on the pressure and on the rapidity of their increase at the front of the detonation wave. Because of this fact, with the increase of the velocity of detonation, of the density of explosive substances, and with the decrease of the width of the zone of chemical reaction, there increases the brisant action, within the zone of which the impact of the impulse pressures exceeds the limit of the strength of the material, and there emerge the significant deformations, which phenomenon leads to the grinding of the brittle materials, and to the intense compaction of the ductile materials.

They determine the brisance of the explosive substances according to the yield of the fractions during the crushing of the rocky (in certain cases metallic) shell around the charge. They estimate the brisant action (the method by L. I. Baron, S. P. Levchik) according to the result of the explosion of the charge of the explosive substances with the mass of 20 grams within the basaltic cubic block (the edge with the length of 150 millimetres), which has been placed within the steel vessel; they determine the yield of the crushed fraction (the size of the particles is less than 7 millimetres). They estimate indirectly the brisance of the explosive substances by the method of measuring the impulse of the explosion according to the degree of compression for the lead cylinder (the test by Hess), for the copper crusher (the brisance measuring device by Kast), or according to the declination of the ballistic pendulum. The indicator of the brisance for the industrial explosive substances according to the test by Hess is 4-23 millimetres.