Global Journal of Science Frontier Research, A: Physics and Space Science, Volume 23 Issue 11

Fig. 4: Macrostructure of the cross section of the hollow copper cylinder after compression with the detonation wave Damageability of Metals under Impulse Loading © 2023 Global Journals 1 Year 2023 24 Frontier Research Volume XXIII Issue ersion I VXI ( A ) Science Global Journal of The approach of the shock wave to the axis of at the unloading stage and spreads in the form of a spall crack transforming into the LSBs in the already "milled" material. The deformation of the material by a shock wave and the damage of the material during unloading are two independent processes. It is noted in [15] that copper and fluoroplastic form a similar system of cracks near the central part of the collapsing sample, which confirms the independence of LSBs of the material used. However, the authors [15] ignored the compressibility of a solid under impulse loading and came to the conclusion that adiabatic shear bands that originated in the already "milled structure," i.e., the structure inside the sample, transform into cracks near the internal cavity. It should be noted that the idea that adiabatic shear bands arise as a result of material deformation is widespread. Ignoring the compressibility of a solid almost invariably leads to an erroneous interpretation of the experiment, since the main processes that determine the impulse behavior of the material are excluded from the consideration. symmetry is accompanied by an increase in the height of such protrusions. Apparently, when the size of the protrusions becomes equal to the distance of the front to the axis, the shock wave stops, since the axial space is occupied by its own protrusions, and the cumulative process terminates by the formation of a reflected shock wave. The exit of the perturbed shock wave onto the free surface is accompanied by the appearance of unloading waves. The sources of unloading waves are free surface areas to which the protrusions of the front approach. Regions of the surface “bulge” under the influence of local unloading waves, and folds of the relief form on the inner surface of the sample. Interference of unloading waves from two nearest folds leads to the formation of spall cracks between the folds , which is clearly seen in Fig. 4. It should be noted that the structure shown in Fig. 4 was formed in two stages. At the first stage, the shock wave, being intensified toward the center, intensively deforms the material, and the grains are crushed and elongated. Damagability occurs Fig. 5: Microstructure of the central part of a steel cylindrical sample