Issue 24

Andrey E. Buzyurkin et alii, Frattura ed Integrità Strutturale, 24 (2013) 102-111; DOI: 10.3221/IGF-ESIS.24.11 110 in the compacted region for the detonation velocity = 5 D km/s. An appreciable non-uniformity in the distribution of parameters is evident from the graphs. Near the axis, both the velocity and temperature are greater than in the region some distance away from it. X, cm Y, cm 8 0 0.5 X, cm Y, cm 0.5 X, cm Y, cm 2 0.5 а) b) c) 6 4 8 2 6 4 8 2 6 4 Figure 16 : Pressure isolines: a) detonation velocity = 7 D km/s; b) detonation velocity = 5 D km/s; c) detonation velocity = 3 D km/s. Ux, cm/msec Y, cm T, K 0.2 0.1 0.05 0.8 0.6 0.4 0.15 0.2 Y, cm 0.2 0.8 0.6 0.4 300 50 150 200 250 Figure 17 : Predicted distributions of the longitudinal velocity x u (a) and temperature T (b) across the compacted region of the sample for the detonation velocity = 5 D km/s. Parts a and b of Fig. 18 show the distributions of the longitudinal velocity x u and temperature T across the compacted region of the sample predicted for the detonation velocity = 3 D km/s. Here, under identical loading parameters, the final sample is quire homogeneous. As a result, it becomes possible to obtain spatially uniform compacted samples. The necessary condition for this is sufficiently low detonation velocity, equal, for the aluminum powder, to 0.3 cm/ m sec. Here, on the one hand, compaction condition (1) should be fulfilled and, on the other, the uniformity of loading parameters across the sample should be ensured. Thus, the compaction of powders with low detonation velocities results in a considerable shrinkage of destruction zones in finish samples and in spatial uniformity of material parameters in their compacted parts. The performed analysis shows that an increase in the decay time of the pressure applied to the sample due to an increase of the explosive thickness or the external loading causes no shrinkage of the destructed region at a fixed propagation velocity of the detonation wave. Simultaneously, a decrease in the propagation velocity of the detonation wave results in an appreciable shrinkage of this region.