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 (6) Determine the value of parameters in Equation (17) for
duration of shock load from Figure 4-5 of NAVFAC P-397.
(tA)N = .5 ms
(tA)F =
1.9 ms
(to)F = 1.6 ms
t'o = (tA)F - (tA)N + (to)F
=
1.9 - .5 + 1.6 = 3.0
ms
Fictitious peak shock pressure:
2ib = 2 x 833.0 = 555.3 psi
Pr =
t'o
3.0
b.
Blast Environment Outside Cubicle.
Problem:
For a given amount of explosives stored in a 3-wall cubicle
without a roof, the pressures anywhere behind the backwall and
sidewalls should not exceed a certain value. Determine the
dimensions of the cubicle and the peak pressures behind the
sidewalls and backwall and out the open front at a range of
200 feet.
Given:
(1) Charge weight, W.
(2) Maximum peak incident pressure, (Pso)max.
Solution:
(1) For the given maximum peak incident pressure, determine
the charge-to-volume ratio, W/V, and hence the volume of
the cubicle using Figure 14.
(2) Determine dimensions of cubicle for given volume.
(3) Determine the scaled distance, R/W1/3.
(4) Using Figure 13, determine the incident pressures behind
the backwall, sidewalls, and front wall. Compare results
with the maximum peak incident pressure.
Calculation:
Given:
(1) W = 125 pounds of Composition B explosive.
(2) (Pso)max = 15 psi.
2.08-60
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