Bulletin of the American Physical Society
21st Biennial Conference of the APS Topical Group on Shock Compression of Condensed Matter
Volume 64, Number 8
Sunday–Friday, June 16–21, 2019; Portland, Oregon
Session H4: MS: Strength & Spall II |
Hide Abstracts |
Chair: George T. Gray III, LANL Room: Pavilion West |
Tuesday, June 18, 2019 9:15AM - 9:30AM |
H4.00001: Measurements of Rayleigh-Taylor growth in solid and liquid copper in the Mbar regime James McNaney, Shon Prisbrey, Channing Huntington, Hye-Sook Park, Bruce Remington, Damian Swift, Chris Wehrenberg, Tom Arsenlis Face-on radiographic measurements of ripple growth in solid and liquid copper have been performed at the OmegaEP laser facility. Pre-imposed ripples of 80\textmu m wavelength were accelerated by the stagnation of a releasing shocked plastic ``reservoir'' which was directly driven by 3-9kJ of laser energy. The state of the copper was varied from solid to liquid by increasing the initial shock amplitude of the loading wave from below to above the Hugoniot shock-melting limit. A comparison with 2-dimensional hydrodynamic simulations indicates that growth in the solid phase is consistent with a strength roughly 2.5-5x that predicted by the commonly used Steinberg-Guinan model while growth in the liquid phase is consistent with simulated no-strength ripple growth. [Preview Abstract] |
Tuesday, June 18, 2019 9:30AM - 9:45AM |
H4.00002: Results of Rayleigh-Taylor tantalum strength experiments at high pressure and high strain rates on NIF Hye-Sook Park, N. R. Barton, C. M. Huntington, P. D. Powell, S. Prisbrey, B. A. Remington, R. E. Rudd, D. C. Swift, C. E. Wehrenberg, A. Arsenlis, J. M. McNaney We are studying tantalum strength at high pressures (up to 8 Mbar), high strain rates (\textasciitilde 10$^{\mathrm{7}}$ s$^{\mathrm{-1}})$ and high strains (\textgreater 30{\%}) under ramped compression condition using Rayleigh-Taylor instability (RTI) properties. Understanding plastic deformation dynamics of materials under these extreme conditions is an area of research of high interest to a number of fields, including meteor impact dynamics and advanced inertial confinement fusion designs. We find that the RTI growth for materials in the solid state, compressed under high pressure and high strain rate conditions, is reduced compared to classical RT, which we assume is due to the material strength (effective lattice viscosity). Our results show that the measured growth factor follows the Livermore Multiscale strength Model (LMS) [2] closely and that the work hardening dominates in this regime. We will describe the experimental results from NIF in comparison with the various strength models. [1] H. --S. Park et al., Phys. Rev. Lett. 114, 065502 (2015). [2] N. Barton, et al., J. App. Physics, 109, 073501 (2011). [Preview Abstract] |
Tuesday, June 18, 2019 9:45AM - 10:15AM |
H4.00003: Exploiting the Unique Capabilities of Richtmyer-Meshkov Instability Strength Measurements at Extreme Strain Rates Invited Speaker: Michael Prime Only recently, Richtmyer-Meshkov Instability (RMI) experiments fielded with the perturbations on a free surface have been used to study strength at strain rates of about 10$^{7}$/second and near zero pressure. When perturbation velocities are measured, the excellent sensitivity to strength makes RMI experiments fairly simple to use for validation of constitutive models. This talk details ongoing efforts to exploit the unique capabilities of RMI beyond simple model validation. First, the use of impact loading rather than high explosives makes the experiments simpler and more accurate to analyze and also allows one to explore a wider range of conditions. Second, the hypothesis that RMI experiments sample only a compact range of strain, strain rate, temperature and pressure is explored to see if an estimated $\textit{average}$ strength value is meaningful and can be used to calibrate rather than just validate a strength model. Third, the ability of RMI to isolate high strain rate effects from high pressure can be used alone or combined with other dynamic experiments at high pressures to check some widely used but not yet validated modeling assumptions. New RMI results on tantalum indicate zero pressure strength at 10$^{7}$//second somewhat exceeding model expectations. The zero pressure RMI results at high rate were then used to predict strength at high pressure using the common assumption of scaling with the density (i.e., pressure) dependence of the shear modulus. Strength estimates at high rates and pressures up to 350 GPa from planar ramp loading and release experiments on the Z machine at Sandia National Laboratories indicate that, for pressures over 100 GPa, the strength significantly exceeds those predictions. [Preview Abstract] |
Tuesday, June 18, 2019 10:15AM - 10:30AM |
H4.00004: High-pressure Pb and Pb-4wt{\%}Sb strength measurements at the National Ignition Facility Andrew Krygier, Philip Powell, Jim McNaney, Channing Huntington, Shon Prisbrey, Bruce Remington, Rob Rudd, Damian Swift, Chris Wehrenberg, Tom Arsenlis, Hye-Sook Park, Peter Graham, Ed Gumbrell, Matt Hill, Andrew Comley, Steve Rothman We study the high-pressure plastic flow behavior of Pb and Pb-4wt{\%}Sb samples dynamically compressed to \textasciitilde 400 GPa peak pressure using the National Ignition Facility lasers. These are the highest-pressure strength experiments ever reported. Our samples have pre-formed sinusoidal ripples that seed the Rayleigh-Taylor (RT) instability and the resulting ripple growth during ramp loading is sensitive to strength. We find that the measured ripple growth factors agree well with hydrodynamic simulations using the Improved Steinberg-Guinan model for high-pressure body-centered-cubic phase of Pb. The inferred peak flow stress for the phase transformed and pressured hardened Pb is \textasciitilde 4 GPa, which is \textasciitilde 250 times larger than its ambient strength. In contrast to antimonial lead at ambient conditions, we find that alloying has no measurable effect on the strength under high strain-rate dynamic compression. This suggests that alloy-hardening effects are dwarfed by strain-hardening under these conditions. [Preview Abstract] |
Tuesday, June 18, 2019 10:30AM - 10:45AM |
H4.00005: Computational and Experimental Hugoniot of Ti64 to 600 GPa Kyle Cochrane, Patricia Kalita, Seth Root, Tommy Ao We present the shock compression of Ti64 (Ti 90w{\%} Al 6w{\%} V 4w{\%}), a widely used titanium alloy with excellent mechanical properties. The Hugoniot is a key parameter for building analytical equations of state. We use density functional theory (DFT) to calculate the principal Hugoniot up to 600 GPa and pair it with corresponding shock experiments. The DFT framework uses Mermin's generalizations to finite temperature. The equation of state values are obtained via ab initio molecular dynamics (AIMD) simulations and the Hugoniot is calculated with Erpenbeck's method using the Rankine-Hugoniot energy equation to 600 GPa. We use Sandia National Laboratories' Z-machine to magnetically launch aluminum flyers to between 11 km/s and 17 km/s which yields 250 GPa to 500 GPa in the Ti64. The simulations show very good agreement with Z data and with previous three stage gas gun data from Sandia's STAR facility up to 250 GPa. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700