Evaluation of copper spall response using Mie-Gruneisen equation-of- state parameters determined from molecular dynamics

F Wang and J Wang and ZP Qi and XY Wu and XG Zeng and X Yang, COMPUTATIONAL MATERIALS SCIENCE, 216, 111883 (2023).

DOI: 10.1016/j.commatsci.2022.111883

In this study, the formation and application of an across-scale modeling approach is presented to study the in-fluence of shock loading conditions on copper spallation performance. Molecular dynamics simulations coupled with multi-scale shock technology are conducted to determine characteristic parameters of the Mie-Gruneisen equation of state involved in the Slater and Dugdale-MacDonald models. Afterwards, the resultant parameters are embedded into the finite element method to explore the dependence of spall strength, strain rate, and damage evolution rate. It is found that an increase in loading velocity promotes the spallation occur in advance. Com-bined with free surface velocity and spall plane pressure, it is also discovered that the material experiences an entire spallation prior to "pullback signal". As expected, the spall strength determined as the maximum stress is higher than that estimated from the free surface velocity. Besides, there is a temperature-rise effect caused by void-induced thermal dissipation during the spallation. Moreover, the position of spall plane is strongly dependent upon flyer thickness, thereby exhibiting a strain rate effect on spallation behavior. A comparison between numerical results and published experimental data highlights the adequacy of such a hybrid method to capture the copper spall response.

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