Gated IR images of shocked surfaces. Page: 4 of 5
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0 15 r.
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0 5 10 15 20 25
mm in object plane
0 5 10 15 20
mm in object plane
1.00 1.75 2.50 3.25
FIGURE 2. (a)IR imae of shocked depped tin couple;
Figure 3 (a) shows the results from polished tin.
Most notable is the variance in the radiance field.
Distinct circular features, some hot and some cold,
relative to the mean, are clearly evident. The
variance is far in excess of the statistical limit
imposed by the detection system. Figures 4 and 5
show normalized radiance values taken from
locations marked by dashed lines in Figures 2(a)
We have simulated the tin experiments using
Sandia National Laboratories' Eulerian mesh CTH
code. Our rectangular, 2-dimensional modeling
included the Detasheet, Delrin and tin, but did not
include the actual detonator geometry (Figure 1).
A detonation wave was started at a point
corresponding to the center of the output area of the
detonator. The equation of state for the explosive
products was approximated using WJWL parameters
for PETN (the principle component of Detasheet).
Mie-Girneisen equation of state data were used for
Delrin and tin. Delrin was modeled as an elastic,
1.50 2.00 2.50 3.00
FI~GURE 3. (a) IR image of shocked polished tin coup;
(b)pruWhotpikc sofW cipoM.
perfectly plastic material while a Steinberg-Cminan-
Lund strength model was used for tin.
Lagrangian tracer particles were placed into the
simulation at equal intervals along the radius just
under the surface of the coupon. The depth of the
tracers was approximately one mesh cell below the
surface for both samples. A point approximately
one third of the way from the center of the coupon
(approximating the location of the breakout sensor)
was used to determine breakout timing. Breakout
was considered to occur when the temperature at
this point rose from ambient to 3000K. Time
histories of temperature at each tracer were
produced using the experimental timing of the
camera gate relative to break-out. To compare the
modeled temperature with the measured radiance
data it was necessary to integrate the radiance
estimated from the modeled temperatures over the
duration of the camera gate. Figures 4 and 5 show
normalized experimental results over-plotted with
the corresponding CPH data.
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Lutz, S. S. (Stephen S.); Turley, W. D. (William Dale); Rightley, P. M. (Paul M.) & Primas, L. E. (Lori E.). Gated IR images of shocked surfaces., article, January 1, 2001; United States. (digital.library.unt.edu/ark:/67531/metadc929127/m1/4/: accessed November 13, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.