Molecular dynamics simulation of cylindrically converging shock response in single crystal Cu

F Tang and ZY Jian and SF Xiao and XF Li and L Wang and BW Huang and HQ Deng and WY Hu, COMPUTATIONAL MATERIALS SCIENCE, 183, 109845 (2020).

DOI: 10.1016/j.commatsci.2020.109845

There are tremendous experimental and simulation studies with regard to the shock response of copper, however, it is believed that the published literatures are seldom focused on response behavior of copper under nonplanar shock loading. Combined with the interaction between a potential wall and atoms, molecular dynamics simulation is performed to investigate the shock response of single crystal Cu under cylindrically converging impact, with the axis of a cylindrical potential wall along the 0 0 1 crystallographic orientation. The results show that affected by anisotropy of wave speed, the surface shape of elastic wavefront is transformed into a quadrangular columnar form from the initial cylindrical one. With the same shock velocity, due to the converging effect, the temperature rise under cylindrical impact is higher than that under planar impact, and the temperature distribution is very complex during shock. The sites for dislocation nucleation are dependent on shock velocity. At the shock velocity of 0.4 km/s, the nucleation and activity of Shockley partial dislocation loops occur in the hot spot regions adjacent to shock front along 1 0 0 and 0 1 0 directions. As shock velocity increases to 0.55 km/s, the shock plasticity starts from the free surface along 1 1 0 and 1-10 directions.

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