Understanding the role of microstructural heterogeneities on the shock wave propagation and defect evolution behavior is essential to predicting the dynamic response of metals. Heterogeneities, such as voids, provide challenges to understanding the wave propagation behavior as the shock-void interaction can collapse the void and result in large plastic strains and significant heating (hot spot formation) in the metal. Accurate modeling of this phenomenon requires predicting the void collapse mechanisms and the related heat generation and dissipation mechanisms (hotspot formation) that determine the microstructure evolution. While molecular dynamics (MD) simulations can model the void collapse behavior, the time/length scale capabilities pose a challenge to connect with continuum models or the experimental scales. Here, this study presents the capability of the newly developed quasi-coarse-grained dynamics (QCGD) method that extends the MD simulations to larger system sizes and longer times to model this phenomenon. This study uses QCGD simulations to investigate the mechanisms of shock wave interactions with pre-existing voids in single-crystal Ta microstructures for variations in shock pressures, void size, and loading orientations. For a given orientation, the plasticity contributions and rates of void collapse are observed to vary with shock pressures and void size. The larger void sizes and higher pressures result in increased temperatures (hot spots) and faster void collapse rates and unravel the variations in the plasticity contributions. In addition, QCGD simulations investigate the post-collapse microstructure evolution as a release wave travels through the hot spot region. The simulations reveal that the reduction in temperatures due to heat dissipation initiates the dynamic recrystallization behavior in the hotspot regions.
Galitskiy, Sergey, et al. "Modeling shock-induced void collapse in single-crystal Ta systems at the mesoscales." International Journal of Plasticity, vol. 164, no. C, Mar. 2023. https://doi.org/10.1016/j.ijplas.2023.103596
Galitskiy, Sergey, Mishra, Avanish, & Dongare, Avinash M. (2023). Modeling shock-induced void collapse in single-crystal Ta systems at the mesoscales. International Journal of Plasticity, 164(C). https://doi.org/10.1016/j.ijplas.2023.103596
Galitskiy, Sergey, Mishra, Avanish, and Dongare, Avinash M., "Modeling shock-induced void collapse in single-crystal Ta systems at the mesoscales," International Journal of Plasticity 164, no. C (2023), https://doi.org/10.1016/j.ijplas.2023.103596
@article{osti_2417901,
author = {Galitskiy, Sergey and Mishra, Avanish and Dongare, Avinash M.},
title = {Modeling shock-induced void collapse in single-crystal Ta systems at the mesoscales},
annote = {Understanding the role of microstructural heterogeneities on the shock wave propagation and defect evolution behavior is essential to predicting the dynamic response of metals. Heterogeneities, such as voids, provide challenges to understanding the wave propagation behavior as the shock-void interaction can collapse the void and result in large plastic strains and significant heating (hot spot formation) in the metal. Accurate modeling of this phenomenon requires predicting the void collapse mechanisms and the related heat generation and dissipation mechanisms (hotspot formation) that determine the microstructure evolution. While molecular dynamics (MD) simulations can model the void collapse behavior, the time/length scale capabilities pose a challenge to connect with continuum models or the experimental scales. Here, this study presents the capability of the newly developed quasi-coarse-grained dynamics (QCGD) method that extends the MD simulations to larger system sizes and longer times to model this phenomenon. This study uses QCGD simulations to investigate the mechanisms of shock wave interactions with pre-existing voids in single-crystal Ta microstructures for variations in shock pressures, void size, and loading orientations. For a given orientation, the plasticity contributions and rates of void collapse are observed to vary with shock pressures and void size. The larger void sizes and higher pressures result in increased temperatures (hot spots) and faster void collapse rates and unravel the variations in the plasticity contributions. In addition, QCGD simulations investigate the post-collapse microstructure evolution as a release wave travels through the hot spot region. The simulations reveal that the reduction in temperatures due to heat dissipation initiates the dynamic recrystallization behavior in the hotspot regions.},
doi = {10.1016/j.ijplas.2023.103596},
url = {https://www.osti.gov/biblio/2417901},
journal = {International Journal of Plasticity},
issn = {ISSN 0749-6419},
number = {C},
volume = {164},
place = {United States},
publisher = {Elsevier},
year = {2023},
month = {03}}
Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, Vol. 459, Issue 2036https://doi.org/10.1098/rspa.2002.1101