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Title: Wiebull Analysis of Variability in Dynamic HEL and Spall Properties of Tantalum.

Abstract

Abstract not provided.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1268228
Report Number(s):
SAND2007-1218C
526700
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the Annaul TMS Meeting held February 25 - March 1, 2007 in Orlando, FL.
Country of Publication:
United States
Language:
English

Citation Formats

Furnish, Michael D., Reinhart, William D., Trott, Wayne Merle, Chhabildas, Lalit C, and Vogler, Tracy. Wiebull Analysis of Variability in Dynamic HEL and Spall Properties of Tantalum.. United States: N. p., 2007. Web.
Furnish, Michael D., Reinhart, William D., Trott, Wayne Merle, Chhabildas, Lalit C, & Vogler, Tracy. Wiebull Analysis of Variability in Dynamic HEL and Spall Properties of Tantalum.. United States.
Furnish, Michael D., Reinhart, William D., Trott, Wayne Merle, Chhabildas, Lalit C, and Vogler, Tracy. Thu . "Wiebull Analysis of Variability in Dynamic HEL and Spall Properties of Tantalum.". United States. doi:. https://www.osti.gov/servlets/purl/1268228.
@article{osti_1268228,
title = {Wiebull Analysis of Variability in Dynamic HEL and Spall Properties of Tantalum.},
author = {Furnish, Michael D. and Reinhart, William D. and Trott, Wayne Merle and Chhabildas, Lalit C and Vogler, Tracy},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}

Conference:
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  • A suite of impact experiments was conducted to assess spatial and shot-to-shot variability in dynamic properties of tantalum. Samples had a uniform refined {approx}20 micron grain structure with a strong axisymmetric [111] crystallographic texture. Two experiments performed with sapphire windows (stresses of approximately 7 and 12 GPa) clearly showed elastic-plastic loading and slightly hysteretic unloading behavior. An HEL amplitude of 2.8 GPa (corresponding to Y 1.5 GPa) was observed. Free-surface spall experiments showed clear wave attenuation and spallation phenomena. Here, loading stresses were {approx} 12.5 GPa and various ratios of impactor to target thicknesses were used. Spatial and shot-to-shot variabilitymore » of the spall strength was {+-} 20%, and of the HEL, {+-} 10%. Experiments conducted with smaller diameter flyer plates clearly showed edge effects in the line and point VISAR records, indicating lateral release speeds of roughly 5 km/s.« less
  • A suite of impact experiments was conducted to assess spatial and shot-to-shot variability in dynamic properties of tantalum. Samples had a uniform refined {approx} 20 micron grain structure with a strong axisymmetric [111] crystallographic texture. An HEL amplitude of 2.8 GPa (corresponding to Y {approx_equal} 1.5 GPa) was observed. Free-surface spall experiments showed clear wave attenuation and spallation phenomena. Here, loading stresses were {approx} 12.5 GPa and various ratios of impactor to target thicknesses were used. Spatial and shot-to-shot variability of the spall strength was {+-}20%, and of the HEL, {+-}10%. Experiments conducted with smaller diameter flyer plates clearly showedmore » edge effects in the line and point VISAR records, indicating lateral release speeds of roughly 5 km/s.« less
  • Copper and tantalum hemishells are externally loaded by a hemishell of PBX 9501 detonated at its pole. Free-surface velocity histories of the metal hemishells are measured at the pole and at 50 from the pole with a Fabry-Perot interferometer. These histories are used to determine spall strengths and depths by simple wave-interaction analyses and are compared with hydro-code (CAVEAT) predictions using simple and void-growth spall models. 8 refs., 4 figs., 1 tab.
  • We have made a careful set of impact wave-profile measurements (16 profiles) on tantalum and tantalum-tungsten alloys at relatively low stresses (to 15 GPa). Alloys used were Ta{sub 97.5}W{sub 2.5} and Ta{sub 90}W{sub 10} (wt. %) with oxygen contents of 30--70 ppM. Information available from these experiments includes Hugoniot, elastic limits, loading fates, spall strength, unloading paths, reshock structure and specimen thickness effects. Hugoniot and spall properties are illustrated, and are consistent with expectations from earlier work. Modeling the tests with the Steinberg-Lund rate-dependent material model provides for an excellent match of the shape of the plastic wave, although themore » release wave is not well modeled. There is also a discrepancy between experiments and calculations regarding the relative timing of the elastic and plastic waves that may be due to texture effects.« less
  • A high energy, massive liner experiment, driven by an explosive flux compressor generator, was conducted at VNIIEF firing point, Sarov, on August 22, 1996. We report results of numerical modeling and analysis we have performed on the solid liner dynamics of this 4.0 millimeter thick aluminum liner as it was imploded from an initial inner radius of 236 mm onto a Central Measuring Unit (CMU), radius 55 mm. Both one- and two-dimensional MHD calculations have been performed, with emphasis on studies of Rayleigh-Taylor instability in the presence of strength and on liner/glide plane interactions. One-dimensional MHD calculations using the experimentalmore » current profile confirm that a peak generator current of 100-105 MA yields radial liner dynamics which are consistent with both glide plane and CMU impact diagnostics. These calculations indicate that the liner reached velocities of 6.9-7.5 km/s before CMU impact. Kinetic energy of the liner, integrated across its radial cross-section, is between 18-22 MJ. Since the initial goal was to accelerate the liner to at least 20 MJ, these calculations are consistent with overall success. Two-dimensional MHD calculations were employed for more detailed comparisons with the measured data set. The complete data set consisted of over 250 separate probe traces. From these data and from their correlation with the MHD calculations, we can conclude that the liner deviated from simple cylindrical shape during its implosion. Two-dimensional calculations have clarified our understanding of the mechanisms responsible for these deformations. Many calculations with initial outer edge perturbations have been performed to assess the role of Rayleigh-Taylor instability. Perturbation wavelengths between 4-32 mm and amplitudes between 8-240 {mu}m have been simulated with the experimental current profiles. When strength is omitted short wavelengths are observed to grow to significant levels; material strength stabilizes such modes in the calculations.« less