Оцінка параметрів повітряних ударних хвиль та захист від них балістичним пінобетоном

Abstract

The parameters of the air shock wave during the detonation of a standard charge of TNT with a mass of 1 kg when it falls on barriers made of ballistic foam concrete of four types and the air shock wave flow around this barrier were studied. The thickness of the ballistic foam concrete samples is 300 mm, the density is 600 kg/m3. Empirical formulas of M.A. Sadovsky were used for the calculations. A satisfactory match of the experimental data with the parameters calculated according to the formulas of M.A. Sadovsky was established. In the experiments, it was shown that the amplitude of air shock wave behind the barrier made of ballistic foam concrete decreases by an average of 8–30 times. Approximate estimates based on the research data of other authors (Belinsky I.V., Khristoforov B.D.) predict a reduction of the compression wave that propagates through ballistic foam concrete by no more than 5–10 times. As a result of experimental researches, it was found that the shock waves from the explosions turned the relatively insignificant upper layer of the foam concrete slabs, which is the «sacrificial» layer, into a compressed powder due to the destruction of the interpore partitions. In the plane of the surface of the foam concrete slabs, the «sacrificial» layer was described by an imaginary circle, which is the projection of the explosion. The size of the «sacrificial» layer of ballistic foam concrete destroyed by air shock wave from the frontal side does not exceed 20–40 mm. Spalling phenomena from the back side of the ballistic foam concrete samples were not observed when the air shock wave fell with amplitude of 0.4–0.6 MPa. There are 2 types of ballistic foam concrete with the most effective damping of the compression wave in it. It was established that the most effective in terms of protecting critical infrastructure facilities from the action of air shock waves are foam concrete models of protective structures, which are reinforced with fiber of composition «A» and «B» with a reinforcing layer of composite material applied. It was determined that in these models the deepest zones of destruction of ballistic foam concrete were observed on the front side of the protective structure.