Analysis of the Processes Accompanying Cylindrical Cumulation
S. N. Buravova
Merzhanov Institute of Structural Macrokinetics and Materials Science, Russian Academy of Sciences, Chernogolovka, Russia
Keywords: cylindrical cumulation, instability, localization, triple shock configuration, shock wave, localized shear bands, unloading wave
Abstract
Response of materials to pulse loading by cylindrical specimens is determined via two interrelated processes: shock wave motion toward the sample axis and perturbation motion in the form of triple shock configurations along the shock wave front. The surface area of the perturbed shock wave front increases due to protrusions strengthened as a result of merging with shock-wave-generated smaller perturbations. Because the front area sharply increases as the shock wave approaches the axis, several large triple shock configurations are formed and the shock wave front is divided into separate sectors in which they oscillate. The collision of powerful shock structures ensures the shock wave front motion toward the axis by removing a portion of the compressed material from the collision zone forward ahead the shock wave front and the additional compaction of the shock-compressed material by longitudinal shock structures under the wave front. The cumulation process is completed when the height of the protrusions becomes equal to the distance from the shock wave front to the axis. The near-axis space is occupied by the front protrusions, and the resulting reflected shock wave slows down the oncoming flow.
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