R. Meyer J. Köhler A. Homburg Explosives

Strength
298
Vessel mortar test
This test is also based on the determination of the range distance of a
heavy projectile. The explosive is suspended in a thick-walled vessel,
and an accurately fitting cap of the vessels is projected. This apparatus
is stronger, and the weight of the charge may be made as large as
500 g.
Large lead block test
The device consists of a lead block with linear dimensions three times
as large as normal. The block has been used to obtain information
about slurries; the method is too expensive for practical work, since
more than one ton of lead must be cast for each shot.
The crater method
This method is based on the comparison of the sizes (volumes) of the
funnels produced in the ground by underground explosions. It is used
for explosives with a large critical diameter only if no other method is
available, since it is inaccurate and the scatter is large.
W Aquarium Test
The sample is exploded under water (in a natural water reservoir or in
a man-made pool), and the pressure of the resulting impact wave is
measured with the aid of lead or copper membranes.
W Specific Energy
For calculations of performance parameters of explosives W Thermodynamic
Calculation of Decomposition Reactions. As far as the
strength of propellants and explosives is concerned, the most relevant
thermodynamically calculable parameter is the W Specific Energy. This
is the amount of energy which is released when the gases in the body
of the explosive (assumed to be compressed in their initial state) are
allowed to expand at the explosion temperature while performing
useful work. In order to illustrate the working performance obtainable
from explosive materials, this magnitude is conventionally reported in
meter-tons per kilogram; in this book, it is also given in joules (J).
The calculated values of the specific energy agree well with the
performance data obtained by conventional tests. This is particularly
true of the tests in which larger samples are employed, but the
apparatus required for such tests is not always available, and the tests
themselves are relatively expensive.
The following empirical formula relating the specific energy to the
relative weight strength is valid in most cases:
weight strength (%) = 0.0746Vspec. energy (in mt/kg)