Evolution of elastic precursor and plastic shock wave in copper via molecular dynamics simulations

18th APS-SCCM; 24th AIRAPT

Perriot, Romain^1 ; Zhakhovsky, Vasily V.^1 ; Inogamov, Nail A.^2 ; Oleynik, Ivan I.^1

University of South Florida, 4202 East Fowler Avenue, Tampa

FL

33620-5700, United States^1

Landau Institute for Theoretical Physics, RAS, Chernogolovka

142432, Russia^2

关键词: Crystallographic directions;    Hugoniot elastic limit;    Large-scale molecular dynamics;    Molecular dynamics simulations;    Orientation dependence;    Orientation dependent;    Single crystal copper;    Single crystal samples;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/500/17/172008/pdf
DOI  :  10.1088/1742-6596/500/17/172008

来源: IOP

【 摘 要 】

Large-scale molecular dynamics (MD) simulations are performed to investigate shock propagation in single crystal copper. It is shown that the P-V plastic Hugoniot is unique regardless of the sample's orientation, its microstructure, or its length. However, the P-V pathway to the final state is not, and depends on many factors. Specifically, it is shown that the pressure in the elastic precursor (the Hugoniot elastic limit (HEL)) decreases as the shock wave propagates in a micron-sized sample. The attenuation of the HEL in sufficiently-long samples is the main source of disagreement between previous MD simulations and experiment: while single crystal experiments showed that the plastic shock speed is orientation-independent, the simulated plastic shock speed was observed to be orientation-dependent in relatively short single-crystal samples. Such orientation dependence gradually disappears for relatively long, micrometer-sized, samples for all three low-index crystallographic directions , , and , and the plastic shock velocities for all three directions approach the one measured in experiment. The MD simulations also demonstrate the existence of subsonic plastic shock waves generated by relatively weak supporting pressures.