Bulletin of the American Physical Society
2005 14th APS Topical Conference on Shock Compression of Condensed Matter
Sunday–Friday, July 31–August 5 2005; Baltimore, MD
Session T3: Equation of State IV |
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Chair: Brad Clements, Los Alamos National Laboratory Room: Hyatt Regency Constellation D |
Thursday, August 4, 2005 1:00PM - 1:15PM |
T3.00001: Equation of State of Aluminum -- Iron Oxide (Fe$_{2}$O$_{3})$ -- Epoxy Composite: Modeling and Experiment Jennifer Jordan, Richard Dick, Louis Ferranti, Naresh Thadhani, Ryan Austin, David McDowell, David Benson We report on the investigation of the equation of state of an Al -- Fe$_{2}$O$_{3}$ -- epoxy composite in the 2-15 GPa pressure range. The composites were prepared by mixing Al and Fe$_{2}$O$_{3}$ powders with epoxy and curing. The equation of state measurements were conducted using an explosive loading technique with piezoelectric pins to measure the shock velocity in the sample and in a donor material. Gas gun experiments were also preformed on the same materials at lower pressures, using PVDF stress gauges to record the input and propagated stress values and shock velocity based on time of travel through the sample thickness. The experimental results presented in the form of pressure versus volume and shock velocity versus particle velocity relation, are compared to mesoscale particle system eulerian finite element simulations and good agreement is achieved. [Preview Abstract] |
Thursday, August 4, 2005 1:15PM - 1:30PM |
T3.00002: Polycrystalline Aluminum Oxynitride Hugoniot and Optical Properties T.F. Thornhill, T.J. Vogler, W.D. Reinhart, L.C. Chhabildas Aluminum oxynitride (AlON) is an interesting ceramic because it is both polycrystalline and transparent. We have conducted plate impact experiments to measure the Hugoniot up to 100 GPa and the spall strength up to the HEL. AlON appears to lose spall strength completely under certain conditions, perhaps due to the propagation of a failure wave. On the other hand, it remains transparent up to at least 5 GPa, and refractive index measurements have been made over this regime. In addition, nonlinear elastic constants have been determined from measurements of elastic shock velocities.\newline \newline *Sandia is a mulitprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy National Nuclear Security Administration under contract DE-AC04-94AL8500. [Preview Abstract] |
Thursday, August 4, 2005 1:30PM - 1:45PM |
T3.00003: Recent advances in modeling Hugoniots with Cheetah Kurt Glaesemann, Laurence Fried The detonation of an energetic material is the result of a complex interaction between kinetic chemical reactions and thermodynamic chemical equilibrium. Unfortunately, little is known concerning the detailed chemical kinetics of reacting energetic materials. Cheetah uses rate laws to treat species with the slowest chemical reactions, while assuming other chemical species are in equilibrium. Cheetah supports a wide range of elements and condensed detonation products and can also be applied to gas phase reactions. Improvements have been made to Cheetah's equilibrium solver, that allow it to find a wider range of thermodynamic states. Many of the difficulties experienced by users in earlier versions of Cheetah have been fixed. New capabilities have also been added. The ultimate result is a code that can be applied to a wide range of shock problems involving both energetic and non-energetic materials. New experimental validations of Cheetah's equation of state methodology have been performed, including both reacted and unreacted Hugoniots. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. [Preview Abstract] |
Thursday, August 4, 2005 1:45PM - 2:00PM |
T3.00004: A Complete EOS for Non-Reacted Explosives Brian Lambourn A complete EOS for non-reactive (NR) explosives is proposed and results are given for PBX9501. The EOS uses the principal isentrope, written in finite strain form, as reference curve for a Mie-Gruneisen EOS. The principal isentrope is defined by fitting available Hugoniot data, after extrapolating it to theoretical maximum density. Temperature can be calculated at any (v,e) state, for any given variation of specific heat at vo. The improvements of this model over other proposed EOS are: 1 The inclusion of initial porosity as a variable, using the Snowplough model; 2 A higher order finite strain representation to fit the Hugoniot more accurately; 3 A second value of Gruneisen Gamma gives the correct Hugoniot asymptote; 4 More accurate temperatures can be evaluated. An improved NR EOS is needed because of the sensitivity to the EOS of SDT reaction rate models, particularly if NR temperature is a parameter. [Preview Abstract] |
Thursday, August 4, 2005 2:00PM - 2:15PM |
T3.00005: Hugoniot measurement and high-pressure phase transition of beta-SiAlON Toshimori Sekine, Takamichi Kobayashi We have measured Hugoniot of beta-Si$_{4}$Al$_{2}$O$_{2}$N$_{6}$ ceramics up to about 120 GPa. The HEL and the onset pressure of phase transformation is smaller than those of beta-Si$_{3}$N$_{4}$. According to shock recovery results of beta-SiAlON, the recovered high-pressure phases are a cubic spinel and amorphous phase. The amount of amorphous phase increases with increasing pressure. Analysis of the high-pressure region of Huginot suggests a series of phase transitions with increasing pressure. A comparison of Hugoniot measurement and recovery results of beta-SiAlON indicates the post-spinel phase will not be quenchable. The partially released states have been determined by the buffer method and the results indicate a large hysteresis. [Preview Abstract] |
Thursday, August 4, 2005 2:15PM - 2:30PM |
T3.00006: Shock Compression, Adiabatic Expansion and Equation of State of Uranium Dioxide K.V. Khishchenko, V.E. Fortov, I.V. Lomonosov, M.V. Zhernokletov, M.A. Mochalov, A.E. Kovalev, I.P. Trusov, A.N. Shuikin Equation of state for matter over wide range of pressures and densities is interesting for modeling of physical phenomena in shock-compressed media. In the present study we have obtained data on the shock compressibility of porous uranium dioxide UO$_2$ samples with initial densities 4.25 and 2~g/cc up to pressures $P \approx 82$~GPa. We have also measured states of UO$_2$ samples in adiabatic release waves using barrier technique down to $P \sim 0.05$~GPa. We propose a semiempirical equation of state $E(P,V)$ for UO$_2$ optimally generalized the newly acquired and available at high energy densities experimental data. The equation of state obtained has a simple analytical form $P=P(E,V)$ and it can be used efficiently in numerical simulations of shock-wave processes. [Preview Abstract] |
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