Constrained model calibration of grain structure dependent spall dynamics in shock-loaded tantalum

We perform a gas gun experiment by shock loading tantalum samples of varying grain structures to assess the suitability of a numerical model for simulating spall behavior. The observed differences in spall strength, as well spallation and re-compression history, are not captured in uncalibrated hydr...

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Bibliographic Details
Published in:Journal of applied physics 2022-08, Vol.132 (8)
Main Authors: Beach, Kory, Horwitz, Jeremy A. K., Maich, Alyssa, White, Elida, Ramos, Dane, Crum-Friedman, Ryan S., Akin, Minta, Najjar, Fady M.
Format: Article
Language:English
Subjects:
Applied physics
Body centered cubic lattice
Compressing
Compressive strength
Crystal pulling
Free surfaces
Gas guns
Grain structure
Mathematical models
Microstructure
Numerical models
Optimization
Parameters
Percolation
Shock loading
Simulation
Single crystals
Spallation
Stability analysis
Tantalum
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Summary:We perform a gas gun experiment by shock loading tantalum samples of varying grain structures to assess the suitability of a numerical model for simulating spall behavior. The observed differences in spall strength, as well spallation and re-compression history, are not captured in uncalibrated hydrodynamic simulations. An optimization is performed on the Johnson spall model to determine the best parameters that fit the observed trends. Linear stability analysis is employed to motivate bounds on those parameters. Herein, optimized simulations agree well with the experimental results, reproducing pullback depth and recompression timescales across the different samples tested. Further, the observed pullback time of the single crystal sample was found to imply, via the stability analysis, a percolation threshold in good agreement with the theoretical value for a body centered cubic lattice. Therefore, the combined linear stability and percolation analysis shows promise and may be applied to other materials with diverse microstructures. Collectively, the findings demonstrate that the model is suitable for reproducing spall-induced free surface behavior across various microstructures, but also points to caution in using model coefficients for uncalibrated microstructures.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0102611