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 E1: ME.4 Strength IV |
Hide Abstracts |
Chair: Tracy Vogler, Sandia National Laboratories Room: Grand Ballroom I |
Monday, July 8, 2013 3:30PM - 3:45PM |
E1.00001: Using Growth and Arrest of Richtmyer-Meshkov Instabilities and Lagrangian Simulations to Study High-Rate Material Strength Michael Prime, Diane Vaughan, Dean Preston, David Oro, William Buttler Rayleigh-Taylor instabilities have been widely used to study the deviatoric (flow) strength of solids at high strain rates. More recently, experiments applying a supported shock through mating surfaces (Atwood number $=$ 1) with geometrical perturbations have been proposed for studying strength at strain rates up to 10$^{\mathrm{7}}$/sec using Richtmyer-Meshkov (RM) instabilities. Buttler et al. [J. Fluid Mech., 2012] recently reported experimental results for RM instability growth but with an unsupported shock applied by high explosives and the geometrical perturbations on the opposite free surface (Atwood number $=$ -1). This novel configuration allowed detailed experimental observation of the instability growth and arrest. We present results and detailed interpretation from numerical simulations of the Buttler experiments on copper. Highly-resolved, two-dimensional simulations were performed using a Lagrangian hydrocode and the Preston-Tonks-Wallace (PTW) strength model. The model predictions show good agreement with the data in spite of the PTW model being calibrated on lower strain rate data. The numerical simulations are used to 1) examine various assumptions previously made in an analytical model, 2) to estimate the sensitivity of such experiments to material strength and 3) to explore the possibility of extracting meaningful strength information in the face of complicated spatial and temporal variations of stress, pressure, and temperature during the experiments. [Preview Abstract] |
Monday, July 8, 2013 3:45PM - 4:00PM |
E1.00002: Inferring yield strength in $\alpha$-phase cerium from a Ricthmyer-Meshkov Instability Frank Cherne, Brian Jensen, Kyle Ramos, John Yeager, Guy Dimonte, Guillermo Terrones, Michael Prime, Kamel Fezzaa, Charles Owens Recent experiments on the 12-mm gas gun known as IMPULSE at the Advanced Photon Source (Argonne, IL) were performed to examine Richtmyer-Meshkov instability (RMI) growth for cerium samples shocked into the $\alpha$-phase. The high resolution images that have been obtained using X-ray phase contrast imaging show spike growth from a machined RMI surface with unprecedented spatial resolution (2-3 microns). Applying the theory developed by G. Dimonte, et al. [PRL {\bf{107}} 264502 (2011)], we have inferred the yield stress for cerium which was shocked into the $\alpha$-phase. We observed that the yield stress decreased as the melt boundary was approached similar to copper. Because the experiments were not performed using an ideal sinusoidal perturbation, molecular dynamics simulations and continuum calculations have been performed looking at the effect of the surface shape used in this work. In this work, a detailed discussion of the analysis will be presented along with a comparison of our calculations with available experimental data. [Preview Abstract] |
Monday, July 8, 2013 4:00PM - 4:15PM |
E1.00003: Investigating iron material strength during phase transitions using Rayleigh-Taylor growth measurements Channing Huntington, Jon Belof, Kerri Bloblaum, Rob Cavallo, Natalie Kostinski, Brian Maddox, Mark May, Hye-Sook Park, Christopher Plechaty, Shon Prisbrey, Bruce Remington, Robert Rudd, David Swift, Russell Wallace, Michael Wilson A solid-solid phase transition between the bcc ($\alpha )$ and hcp ($\varepsilon )$ lattice structures in iron is known to occur as the material is compressed. When kept below its melting point, an effective increase in the macroscopic strength of the material accompanies this phase transition. Understanding the strength of iron throughout the deformation process is important for improving models of planetary structure, including interpretation of seismic measurements on Earth. To explore iron strength at high pressures and strain rates, we have performed experiments at the OMEGA laser. The laser drive produces a pressure near 1 Mbar on a thin Fe disk with a sinusoidal ripple pattern imposed on its face. The ripples seed the Rayleigh-Taylor (RT) instability, the growth of which is suppressed by the material strength of the sample. The ripple amplitude is diagnosed with x-ray radiography, and their growth is compared to values from simulations using different material strength models. This work will be compared to previous, similar experiments at 0.1 -- 0.3 Mbar pressures (J. Belof et al., AIP Conf. Proc. 2012). [Preview Abstract] |
Monday, July 8, 2013 4:15PM - 4:30PM |
E1.00004: Solid state Rayleigh-Taylor measurements in Ta and V at high pressures and strain rates Bruce A. Remington, Hye-Sook Park, Robert Cavallo, Shon Prisbrey, Robert Rudd, Chris Plechaty, Chris Wehrenberg, Brian Maddox, Natalie Kostinski, Matthew Terry, C.M. Huntington We will report on Rayleigh-Taylor (RT) strength experiments in solid-state driven foils of vanadium and tantalum at high strain rates ($\sim$1.e7 1/s) and high pressures ($\sim$1 Mbar), where softening (a decrease in strength) is observed when the strains get large. When the single-mode RT bubble penetration in this plastic flow regime reaches $\sim$20-30\% of the initial foil thickness, the inferred high strength in the foils starts to drop. In the extreme, this drop in strength may be an indication of incipient failure. We will discuss the similarities and differences between the observed softening in the V-RT and Ta-RT experiments, and consider the implications for future planned experiments on the National Ignition Facility (NIF) at higher pressures ($\sim$5 Mbar), but similar strain rates. [Preview Abstract] |
Monday, July 8, 2013 4:30PM - 4:45PM |
E1.00005: Hydrodynamic instabilities and dynamic strength Raevskiy Vicktor The paper presents results of numerical-theoretical and experimental investigations of influence of shear strength on growth of the Richtmyer-Meshkov instability and the Rayleigh-Taylor instability. It is revealed that, for monochromatic perturbations at accelerated boundary of a solid, there are the critical conditions when the perturbation growth is limited. High sensitivity of perturbation growth to dynamic strength near the stability boundary allowed to develop the method for determination of dynamic strengths of substances in wide range of pressures and strain rates (? $\sim$ 10 $\div$ 300 GPa, strain rate $\sim$ 10E4 $\div$ 10E7 1/s). The paper includes setup and results of series of tests devoted to investigation of dynamic strengths of some metals (??, ?u, AL, Be). [Preview Abstract] |
Monday, July 8, 2013 4:45PM - 5:15PM |
E1.00006: Dynamic strength and instabilities of Rayleigh-Taylor and Richtmayer-Meshkov Invited Speaker: Victor Raevsky |
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