Expanding the envelope for spall modeling using porosity mechanics incorporating microinertia

Spall response and its connection to material microstructure are of significant interest across a range of loading conditions, including those produced by impact, explosives, or lasers. In this study, spall failure is simulated for conditions that access a range of characteristic time scales. Material failure is simulated using a Cocks-Ashby based damage model [1,2], in a large-deformation hydrocode (ALE3D) [3]. Differences in the macroscopic response and in the corresponding microscopic stress conditions are observed, with the loading conditions having a strong influence on the porosity growth associated with spall. Results for simulated free-surface velocities confirm the value of complementary post-mortem analysis in experiments. The model accounts for microinertial effects and provides information about potential discrepancies between microscopic stress states and the nominal spall strength inferred from velocimetry. The observations including microinertia suggest a route to improved spall performance in specially engineered materials.

References

[1] N. Barton, “Results from a new Cocks-Ashby style porosity model,” in AIP Conference Proceedings, Vol. 1793 (2017) p. 100029.

[2] S. B. Qamar, J. A. Moore, and N. R. Barton, "A continuum damage approach to spallation and the role of microinertia", Journal of Applied Physics, 131, 085901 (2022) https://doi.org/10.1063/5.0078182.

[3] C. R. Noble, et al., “ALE3D: An Arbitrary Lagrangian-Eulerian Multi-Physics Code,” LLNL-TR-732040 (2017), https://doi.org/10.2172/1361589