Bulletin of the American Physical Society
18th Biennial Intl. Conference of the APS Topical Group on Shock Compression of Condensed Matter held in conjunction with the 24th Biennial Intl. Conference of the Intl. Association for the Advancement of High Pressure Science and Technology (AIRAPT)
Volume 58, Number 7
Sunday–Friday, July 7–12, 2013; Seattle, Washington
Session U6: ME.4 Strength VI |
Hide Abstracts |
Chair: Hyunchae Cynn, Lawrence Livermore National Laboratory Room: Cascade II |
Thursday, July 11, 2013 11:00AM - 11:30AM |
U6.00001: Multiscale strength (MS) models: their foundation, their successes, and their challenges Invited Speaker: Robert Rudd Multiscale strength (MS) models are constructed to capture a natural hierarchy in the deformation of metals such as V and Ta starting with atomic bonding and extending up through the mobility of individual dislocations, the evolution of dislocation networks and so on until the ultimate material response at the scale of an experiment. In practice, the hierarchy is described by quantum mechanics, molecular dynamics, dislocation dynamics, and so on, ultimately informing a continuum constitutive model. We review the basic models and describe their extension to plastic flow in shocked metals and the response of polycrystalline materials. In experimental systems that match the assumptions of the multiscale strength models, they work surprisingly well, both for fundamental experiments like in-situ single crystal diffraction, and for more integral experiments like Rayleigh-Taylor plastic flow experiments. There are also clear challenges, however. The current MS models do not include failure, and they are expensive to create, due to the large amounts of computer time needed. Still, MS models provide compelling insight into metals under extreme pressures and strain rates.\\[4pt] In collaboration with A. Arsenlis, N.R. Barton, R. Becker, J.L. Belof, R.M. Cavallo, A.J. Comley, C.M. Wehrenberg, B.R. Maddox, J. Marian, H.-S. Park, C. Plechaty, S.T. Prisbrey, P. Qian, C.E. Wehrenberg, and B.A. Remington, Lawrence Livermore National Laboratory. [Preview Abstract] |
Thursday, July 11, 2013 11:30AM - 11:45AM |
U6.00002: Strain anisotropy and shear strength of shock compressed tantalum measured from in-situ Laue diffraction Christopher Wehrenberg, Matt Terry, Brian Maddox, Andrew Comley, Hye-Sook Park, Shon Prisbrey, James Hawreliak, Justin Wark, Andrew Higginbotham, Bruce Remington Laser driven shock experiments, performed at the Omega facility, studied the dynamic yield strength and lattice dynamics of single crystal tantalum using in-situ Laue diffraction. Tantalum samples were shocked along the [100] direction to peak stresses up to 60 GPa and probed using the bremsstrahlung radiation from an imploding CH capsule x-ray source. Diffraction spots for both the undriven and driven regions of the sample were recorded simultaneously on time-integrated image plate detectors. The strain anisotropy was measured from the position shift of the driven diffraction spot and the total strain state was found using the volumetric strain from VISAR. Yield strength measurements were inferred from the data and compared with predictions from various models, including the LLNL multi-scale strength model for Ta. [Preview Abstract] |
Thursday, July 11, 2013 11:45AM - 12:00PM |
U6.00003: Investigations into rapid uniaxial compression of polycrystalline targets using femtosecond X-ray diffraction David McGonegle, Andrew Higginbotham, Sam Vinko, Justin Wark, Eric Galtier, Hae-Ja Lee, Despina Milathianaki, Bob Nagler, Emma McBride, Malcolm McMahon When a material is uniaxially shock or ramp compressed to high pressures on ultrafast timescales, the rate at which the lattice response occurs can compete with the kinetics of the plasticity, and thus the material can deviate greatly from a hydrostatic response, and the assumption that the difference between the longitudinal and transverse strains in a sample remains small becomes increasingly invalid. We present analysis of X-ray diffraction data from laser shocked polycrystalline targets subjected to large strains, as well as large strain anisotropies, factors of which many existing models fail to correctly take account. We demonstrate that by breaking the symmetry of the experiment, using a tilted target geometry, it is possible to measure these strain anisotropies in a polycrystal. We present data acquired using this technique performed on the MEC beamline at LCLS, and discuss possible future experiments, such as investigations into the Voigt-Reuss parameter using such emerging 4th generation light sources. [Preview Abstract] |
Thursday, July 11, 2013 12:00PM - 12:15PM |
U6.00004: ABSTRACT WITHDRAWN |
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