A LINEAR SHAPED CHARGE NEUTRON RADIOGRAPHY PRECISE DETECTION SCHEME
Neutron radiography was researched to detect the linear density of explosive in linear shaped charge (LSC), to determine its distribution uniformity and defective. The clear images of some samples were obtained by neutron radiography, and were processed to obtain the linear density of inner explosive. The defectives such as sparseness, discontinuity and cavity were shown clearly in the images. The method, with more intuitive and more reliable results, is more direct and simpler than existing quality testing methods for LSC, and most important, the method is a non-destructive one. This new method is of significance to the precise test of LSC and its application in precise blasting; in addition, it could be used in quality test of cord type explosive device.
Jet penetration in plexiglas
Abstract The effect of compressibility on the penetration of a continuous jet in Plexiglas has been investigated experimentally and analytically. Cine flash radiography was used to measure the penetration velocity of a copper jet in Plexiglas. The analysis treated compressible and incompressible theory with and without using the virtual origin assumption. The form of the compressible theory used was based on the treatment described by Flis and Chou. Reasonably good agreement was obtained between the jet penetration velocities calculated using compressible theory and those determined experimentally.
The Initiation of Covered Composition B by a Metal Jet
The initiation and build-up to detonation of Composition B covered by steel barrier plates and impacted by a shaped-charge jet has been studied. Two different barrier thicknesses were used representing strong and weak shock initiating systems. The results showed that, in both cases, a shock (designated the precursor shock) that travelled ahead of the penetrating jet and entered the explosive was roduced when the jet impacted the steel surface. The strong precursor shock from the thin barrier system produced initiation close to the explosive surface while for the weak precursor shock from the thick barrier system there was a long run to detonation (40 mm, 11 μs). In the latter case, close to the onset of detonation, a retonation was observed moving back through the previously shocked explosive which was expanding radially. These observations are used to discuss and explain some of the apparent anomalies in previously reported work. The effect of the precursor shock on the classical jet penetration theory was estimated.